diff --git a/packages/core/src/services/index.ts b/packages/core/src/services/index.ts
index 6ee342bc..b3eb1a26 100644
--- a/packages/core/src/services/index.ts
+++ b/packages/core/src/services/index.ts
@@ -54,6 +54,7 @@ export {
   DEFAULT_GRID_STEP,
   type SnapServices,
   snapAngleToList,
+  snapPointAlongAngleRay,
   snapPointToAngle,
   snapPointToGrid,
   snapScalar,
diff --git a/packages/core/src/services/snap.test.ts b/packages/core/src/services/snap.test.ts
index 1a4ddb38..fa076fa3 100644
--- a/packages/core/src/services/snap.test.ts
+++ b/packages/core/src/services/snap.test.ts
@@ -3,6 +3,7 @@ import {
   DEFAULT_ANGLE_STEP,
   DEFAULT_GRID_STEP,
   snapAngleToList,
+  snapPointAlongAngleRay,
   snapPointToAngle,
   snapPointToGrid,
   snapScalar,
@@ -87,6 +88,54 @@ describe('snapPointToAngle', () => {
   })
 })
 
+describe('snapPointAlongAngleRay', () => {
+  test('stays exactly on the 15° ray while distance-snapping to the grid step', () => {
+    const from: Vec2 = [0, 0]
+    const cursor: Vec2 = [2, 0.5] // ≈14° — snaps to 15°
+    const snapped = snapPointAlongAngleRay(from, cursor, Math.PI / 12, 0.25)
+    expect(Math.atan2(snapped[1], snapped[0])).toBeCloseTo(Math.PI / 12, 10)
+    const distance = Math.hypot(snapped[0], snapped[1])
+    expect(distance / 0.25).toBeCloseTo(Math.round(distance / 0.25), 10)
+  })
+
+  test('grid-snapping after the angle projection would pull the point off the ray', () => {
+    const from: Vec2 = [0, 0]
+    const cursor: Vec2 = [2, 0.5]
+    const offRay = snapPointToAngle(from, cursor, Math.PI / 12, 0.25)
+    expect(Math.atan2(offRay[1], offRay[0])).not.toBeCloseTo(Math.PI / 12, 4)
+  })
+
+  test('45° back-compat: locks to the diagonal with grid-multiple distance', () => {
+    const from: Vec2 = [1, 1]
+    const cursor: Vec2 = [2.1, 1.9] // near 45° from `from`
+    const snapped = snapPointAlongAngleRay(from, cursor, Math.PI / 4, 0.25)
+    expect(Math.atan2(snapped[1] - 1, snapped[0] - 1)).toBeCloseTo(Math.PI / 4, 10)
+    const distance = Math.hypot(snapped[0] - 1, snapped[1] - 1)
+    expect(distance / 0.25).toBeCloseTo(Math.round(distance / 0.25), 10)
+  })
+
+  test('preserves the projected distance when no distanceStep is given', () => {
+    const from: Vec2 = [0, 0]
+    const cursor: Vec2 = [1, 0.05] // near 0°
+    const snapped = snapPointAlongAngleRay(from, cursor, Math.PI / 12)
+    expect(snapped[0]).toBeCloseTo(1, 10) // projection of (1, 0.05) onto 0° ray
+    expect(snapped[1]).toBeCloseTo(0, 10)
+  })
+
+  test('returns `from` for a zero-length segment', () => {
+    expect(snapPointAlongAngleRay([2, 3], [2, 3], Math.PI / 12, 0.25)).toEqual([2, 3])
+  })
+
+  test('is idempotent on its own output', () => {
+    const from: Vec2 = [0.5, -1]
+    const cursor: Vec2 = [3.2, 0.4]
+    const once = snapPointAlongAngleRay(from, cursor, Math.PI / 12, 0.5)
+    const twice = snapPointAlongAngleRay(from, once, Math.PI / 12, 0.5)
+    expect(twice[0]).toBeCloseTo(once[0], 10)
+    expect(twice[1]).toBeCloseTo(once[1], 10)
+  })
+})
+
 describe('snapAngleToList', () => {
   test('snaps to the nearest entry within tolerance', () => {
     const targets = [0, Math.PI / 2, Math.PI, (3 * Math.PI) / 2]
diff --git a/packages/core/src/services/snap.ts b/packages/core/src/services/snap.ts
index faac9c74..3c10ba69 100644
--- a/packages/core/src/services/snap.ts
+++ b/packages/core/src/services/snap.ts
@@ -15,7 +15,7 @@ export type Vec3 = readonly [number, number, number]
 /** Default planar grid spacing in meters. Matches the editor's wall tool. */
 export const DEFAULT_GRID_STEP = 0.25
 
-/** Default angle-snap step — π/12 = 15°. Wall tools also use π/4 (45°). */
+/** Default angle-snap step — π/12 = 15°. */
 export const DEFAULT_ANGLE_STEP = Math.PI / 12
 
 // ─── Grid snap ────────────────────────────────────────────────────────
@@ -111,6 +111,32 @@ export function snapPointToAngle(
   return gridStep == null ? projected : snapPointToGrid(projected, gridStep)
 }
 
+/**
+ * Snaps a cursor point onto the nearest angle ray from `from` (multiples of
+ * `angleStep`), projecting the cursor onto that ray, then snaps the distance
+ * ALONG the ray to `distanceStep`. Unlike `snapPointToAngle` with a
+ * `gridStep`, the result stays exactly on the snapped ray — grid-snapping
+ * after the angle projection pulls points off non-axis rays.
+ */
+export function snapPointAlongAngleRay(
+  from: Vec2,
+  cursor: Vec2,
+  angleStep: number = DEFAULT_ANGLE_STEP,
+  distanceStep?: number,
+): Vec2 {
+  const dx = cursor[0] - from[0]
+  const dz = cursor[1] - from[1]
+  if (dx === 0 && dz === 0) return [from[0], from[1]]
+  const angle = Math.atan2(dz, dx)
+  const snappedAngle = angleStep > 0 ? Math.round(angle / angleStep) * angleStep : angle
+  const dirX = Math.cos(snappedAngle)
+  const dirZ = Math.sin(snappedAngle)
+  const projected = dx * dirX + dz * dirZ
+  const distance =
+    distanceStep != null && distanceStep > 0 ? snapScalar(projected, distanceStep) : projected
+  return [from[0] + dirX * distance, from[1] + dirZ * distance]
+}
+
 /**
  * Snaps an angle (in radians) to the nearest entry in `snapAngles` (also in
  * radians). Returns the original angle if no entry is within `toleranceRad`.
diff --git a/packages/editor/src/components/editor-2d/floorplan-registry-move-overlay.tsx b/packages/editor/src/components/editor-2d/floorplan-registry-move-overlay.tsx
index ee482975..c87211c0 100644
--- a/packages/editor/src/components/editor-2d/floorplan-registry-move-overlay.tsx
+++ b/packages/editor/src/components/editor-2d/floorplan-registry-move-overlay.tsx
@@ -428,7 +428,8 @@ export function FloorplanRegistryMoveOverlay() {
       // 1) Grid snap baseline. Fresh catalog placement is absolute under
       // the cursor; existing moves preserve the cursor's grab offset.
       const gridStep = useEditor.getState().gridSnapStep
-      const snap = (value: number) => Math.round(value / gridStep) * gridStep
+      const snap = (value: number) =>
+        event.shiftKey ? value : Math.round(value / gridStep) * gridStep
       const resolved = resolvePlanarCursorPosition({
         cursor: [m[0], m[1]],
         original: [originalPosition[0], originalPosition[2]],
@@ -442,11 +443,11 @@ export function FloorplanRegistryMoveOverlay() {
       // 2) Alignment snap layered on top. Treat the grid-snapped point
       // as the "proposed" position so alignment competes from a stable
       // base rather than the raw cursor jitter. Alt bypasses alignment
-      // entirely — same affordance Path 1 advertises in its "No Snap"
+      // entirely; Shift bypasses both grid and alignment
       // hint chip.
       let finalX = gridX
       let finalZ = gridZ
-      if (!event.altKey && candidateAnchors.length > 0) {
+      if (!(event.altKey || event.shiftKey) && candidateAnchors.length > 0) {
         // Translate the cached local bbox to the proposed pos to get the
         // moving anchors at that location. The entry's untransformed
         // bbox is in world meters relative to the node's origin, so a
diff --git a/packages/editor/src/components/editor/floorplan-panel.tsx b/packages/editor/src/components/editor/floorplan-panel.tsx
index 1e878c9f..f9bf5cb0 100644
--- a/packages/editor/src/components/editor/floorplan-panel.tsx
+++ b/packages/editor/src/components/editor/floorplan-panel.tsx
@@ -8,6 +8,7 @@ import {
   type CeilingNode,
   type ColumnNode,
   calculateLevelMiters,
+  DEFAULT_ANGLE_STEP,
   type DoorNode,
   type ElevatorNode,
   emitter,
@@ -38,6 +39,7 @@ import {
   StairSegmentNode as StairSegmentNodeSchema,
   sampleWallCenterline,
   sceneRegistry,
+  snapPointAlongAngleRay,
   useInteractive,
   useLiveNodeOverrides,
   useLiveTransforms,
@@ -47,7 +49,7 @@ import {
   ZoneNode as ZoneNodeSchema,
   type ZoneNode as ZoneNodeType,
 } from '@pascal-app/core'
-import { useAlignmentGuides, useWallSnapIndicator } from '@pascal-app/editor'
+import { useAlignmentGuides, useSegmentDraftChain, useWallSnapIndicator } from '@pascal-app/editor'
 import { getSceneTheme, useViewer } from '@pascal-app/viewer'
 import { Command, Ruler } from 'lucide-react'
 import {
@@ -135,12 +137,10 @@ import {
   DEFAULT_STAIR_WIDTH,
 } from '../tools/stair/stair-defaults'
 import {
-  createWallOnCurrentLevel,
   isSegmentLongEnough,
   snapWallDraftPoint,
   snapWallDraftPointDetailed,
   snapPointToGrid as snapWallPointToGrid,
-  WALL_FINE_GRID_STEP,
   WALL_GRID_STEP,
   type WallPlanPoint,
 } from '../tools/wall/wall-drafting'
@@ -220,8 +220,7 @@ const FLOORPLAN_GUIDE_SELECTION_STROKE_WIDTH = 0.05
 const FLOORPLAN_GUIDE_HANDLE_HINT_OFFSET = 72
 const FLOORPLAN_GUIDE_HANDLE_HINT_PADDING_X = 92
 const FLOORPLAN_GUIDE_HANDLE_HINT_PADDING_Y = 48
-const FLOORPLAN_GUIDE_ROTATION_SNAP_DEGREES = 45
-const FLOORPLAN_GUIDE_ROTATION_FINE_SNAP_DEGREES = 1
+const FLOORPLAN_GUIDE_ROTATION_SNAP_DEGREES = 15
 const FLOORPLAN_VIEW_ROTATION_DEG = 90
 const FLOORPLAN_ROTATION_DEGREES_PER_PIXEL = 0.35
 const FLOORPLAN_VIEW_ANIMATION_TIME_CONSTANT_MS = 90
@@ -1277,7 +1276,7 @@ function buildGuideResizeDraft(
 function buildGuideRotationDraft(
   interaction: GuideInteractionState,
   pointerSvg: SvgPoint,
-  useFineIncrement: boolean,
+  bypassSnap: boolean,
 ): GuideTransformDraft {
   const pointerVector = subtractSvgPoints(pointerSvg, interaction.centerSvg)
 
@@ -1292,12 +1291,9 @@ function buildGuideRotationDraft(
 
   const rawRotationSvg =
     Math.atan2(pointerVector[1], pointerVector[0]) - interaction.cornerBaseAngle
-  const snappedRotationSvg = snapAngleToIncrement(
-    rawRotationSvg,
-    useFineIncrement
-      ? FLOORPLAN_GUIDE_ROTATION_FINE_SNAP_DEGREES
-      : FLOORPLAN_GUIDE_ROTATION_SNAP_DEGREES,
-  )
+  const snappedRotationSvg = bypassSnap
+    ? rawRotationSvg
+    : snapAngleToIncrement(rawRotationSvg, FLOORPLAN_GUIDE_ROTATION_SNAP_DEGREES)
 
   return {
     guideId: interaction.guideId,
@@ -2174,49 +2170,29 @@ function isPointNearPlanPoint(a: WallPlanPoint, b: WallPlanPoint, threshold = 0.
   return Math.abs(a[0] - b[0]) < threshold && Math.abs(a[1] - b[1]) < threshold
 }
 
-function calculatePolygonSnapPoint(
-  lastPoint: WallPlanPoint,
-  currentPoint: WallPlanPoint,
-): WallPlanPoint {
-  const [x1, y1] = lastPoint
-  const [x, y] = currentPoint
-  const dx = x - x1
-  const dy = y - y1
-  const absDx = Math.abs(dx)
-  const absDy = Math.abs(dy)
-  const horizontalDist = absDy
-  const verticalDist = absDx
-  const diagonalDist = Math.abs(absDx - absDy)
-  const minDist = Math.min(horizontalDist, verticalDist, diagonalDist)
-
-  if (minDist === diagonalDist) {
-    const diagonalLength = Math.min(absDx, absDy)
-    return [x1 + Math.sign(dx) * diagonalLength, y1 + Math.sign(dy) * diagonalLength]
-  }
-
-  if (minDist === horizontalDist) {
-    return [x, y1]
-  }
-
-  return [x1, y]
-}
-
 function snapPolygonDraftPoint({
   point,
   start,
   angleSnap,
+  bypassSnap,
 }: {
   point: WallPlanPoint
   start?: WallPlanPoint
   angleSnap: boolean
+  bypassSnap?: boolean
 }): WallPlanPoint {
-  const snappedPoint: WallPlanPoint = [snapToHalf(point[0]), snapToHalf(point[1])]
+  if (bypassSnap) return point
 
   if (!(start && angleSnap)) {
-    return snappedPoint
+    return [snapToHalf(point[0]), snapToHalf(point[1])]
   }
 
-  return calculatePolygonSnapPoint(start, snappedPoint)
+  // 15° angle snap from the raw point, with the distance snapped along the
+  // ray to the grid step — grid-snapping the point itself would pull the
+  // vertex off non-axis rays (and matches the 3D slab / ceiling tools).
+  return [
+    ...snapPointAlongAngleRay(start, point, DEFAULT_ANGLE_STEP, useEditor.getState().gridSnapStep),
+  ]
 }
 
 function pointMatchesWallPlanPoint(
@@ -5508,16 +5484,18 @@ export function FloorplanPanel({
   )
   const floorplanOpeningLocalY = useMemo(() => {
     if (movingNode?.type === 'door' || movingNode?.type === 'window') {
-      return snapToHalf(movingNode.position[1])
+      return shiftPressed ? movingNode.position[1] : snapToHalf(movingNode.position[1])
     }
 
     if (isWindowBuildActive) {
       // Floorplan is top-down, so new windows need an explicit wall-local height.
-      return snapToHalf(FLOORPLAN_DEFAULT_WINDOW_LOCAL_Y)
+      return shiftPressed
+        ? FLOORPLAN_DEFAULT_WINDOW_LOCAL_Y
+        : snapToHalf(FLOORPLAN_DEFAULT_WINDOW_LOCAL_Y)
     }
 
     return 0
-  }, [isWindowBuildActive, movingNode])
+  }, [isWindowBuildActive, movingNode, shiftPressed])
   const isMarqueeSelectionToolActive =
     mode === 'select' &&
     floorplanSelectionTool === 'marquee' &&
@@ -7566,9 +7544,10 @@ export function FloorplanPanel({
           return
         }
 
+        const bypassSnap = shiftPressed || event.shiftKey
         const nextDraft =
           guideInteraction.mode === 'rotate'
-            ? buildGuideRotationDraft(guideInteraction, svgPoint, shiftPressed)
+            ? buildGuideRotationDraft(guideInteraction, svgPoint, bypassSnap)
             : guideInteraction.mode === 'translate'
               ? buildGuideTranslateDraft(guideInteraction, svgPoint)
               : buildGuideResizeDraft(guideInteraction, svgPoint)
@@ -7625,15 +7604,14 @@ export function FloorplanPanel({
           return
         }
 
-        // Wall endpoint move: grid snap only (no 45° angle snap from the
-        // fixed corner — that's draft-only behaviour). Shift switches
-        // to the fine grid step for precision.
+        // Wall endpoint move: grid snap only. Shift bypasses all snap.
+        const bypassSnap = shiftPressed || event.shiftKey
         const snapResult = snapWallDraftPointDetailed({
           point: planPoint,
           walls,
           ignoreWallIds: [dragState.wallId],
-          step: shiftPressed ? WALL_FINE_GRID_STEP : undefined,
-          magnetic: useEditor.getState().magneticSnap,
+          bypassSnap,
+          magnetic: !bypassSnap && useEditor.getState().magneticSnap,
         })
         const snappedPoint = snapResult.point
         // Magnetic beacon at the endpoint when it locked onto existing geometry.
@@ -7674,6 +7652,7 @@ export function FloorplanPanel({
           )
 
           if (
+            !bypassSnap &&
             !(
               previousDraft &&
               pointsEqual(previousDraft.start, nextDraft.start) &&
@@ -7702,7 +7681,8 @@ export function FloorplanPanel({
       }
 
       const chord = getWallChordFrame(wall)
-      const snappedPoint: WallPlanPoint = shiftPressed
+      const bypassSnap = shiftPressed || event.shiftKey
+      const snappedPoint: WallPlanPoint = bypassSnap
         ? planPoint
         : [snapToHalf(planPoint[0]), snapToHalf(planPoint[1])]
       const rawCurveOffset = -(
@@ -7711,7 +7691,7 @@ export function FloorplanPanel({
       )
       const nextCurveOffset = normalizeWallCurveOffset(
         wall,
-        shiftPressed ? rawCurveOffset : snapToHalf(rawCurveOffset),
+        bypassSnap ? rawCurveOffset : snapToHalf(rawCurveOffset),
       )
 
       if (curveDragState.currentCurveOffset === nextCurveOffset) {
@@ -7721,7 +7701,9 @@ export function FloorplanPanel({
       curveDragState.currentCurveOffset = nextCurveOffset
       setWallCurveDraft({ wallId: wall.id, curveOffset: nextCurveOffset })
       setCursorPoint(snappedPoint)
-      sfxEmitter.emit('sfx:grid-snap')
+      if (!bypassSnap) {
+        sfxEmitter.emit('sfx:grid-snap')
+      }
     }
 
     const commitGuideInteraction = (event: PointerEvent) => {
@@ -7739,9 +7721,10 @@ export function FloorplanPanel({
       }
 
       const svgPoint = getSvgPointFromClientPoint(event.clientX, event.clientY)
+      const bypassSnap = shiftPressed || event.shiftKey
       const nextDraft = svgPoint
         ? interaction.mode === 'rotate'
-          ? buildGuideRotationDraft(interaction, svgPoint, shiftPressed)
+          ? buildGuideRotationDraft(interaction, svgPoint, bypassSnap)
           : interaction.mode === 'translate'
             ? buildGuideTranslateDraft(interaction, svgPoint)
             : buildGuideResizeDraft(interaction, svgPoint)
@@ -7949,7 +7932,10 @@ export function FloorplanPanel({
         return
       }
 
-      const snappedPoint: WallPlanPoint = [snapToHalf(planPoint[0]), snapToHalf(planPoint[1])]
+      const bypassSnap = shiftPressed || event.shiftKey
+      const snappedPoint: WallPlanPoint = bypassSnap
+        ? planPoint
+        : [snapToHalf(planPoint[0]), snapToHalf(planPoint[1])]
       setCursorPoint(snappedPoint)
 
       const currentDraft = siteBoundaryDraftRef.current
@@ -7962,7 +7948,9 @@ export function FloorplanPanel({
         return
       }
 
-      sfxEmitter.emit('sfx:grid-snap')
+      if (!bypassSnap) {
+        sfxEmitter.emit('sfx:grid-snap')
+      }
 
       const nextPolygon = [...currentDraft.polygon]
       nextPolygon[dragState.vertexIndex] = snappedPoint
@@ -8037,6 +8025,7 @@ export function FloorplanPanel({
     exitSiteEditingToSelect,
     getPlanPointFromClientPoint,
     setSiteBoundaryLivePreview,
+    shiftPressed,
     site,
     siteBoundaryWorldPolygon,
     siteVertexDragState,
@@ -8176,25 +8165,26 @@ export function FloorplanPanel({
       stopPropagation: () => {},
     } as any)
   }, [])
+  // Emits `planPoint` unchanged — callers own snapping. Re-quantizing here
+  // (the old behaviour) destroyed magnetic corner / midpoint snaps the draft
+  // branches had already resolved, desyncing the 2D pipeline from the 3D
+  // tools that subscribe to these grid events.
   const emitFloorplanGridEvent = useCallback(
     (
       eventType: 'move' | 'click' | 'double-click',
       planPoint: WallPlanPoint,
       nativeEvent: ReactMouseEvent<SVGSVGElement> | ReactPointerEvent<SVGSVGElement>,
     ) => {
-      const snappedPoint = getSnappedFloorplanPoint(planPoint)
       const cos = Math.cos(buildingRotationY)
       const sin = Math.sin(buildingRotationY)
-      const worldX = buildingPosition[0] + snappedPoint[0] * cos + snappedPoint[1] * sin
-      const worldZ = buildingPosition[2] - snappedPoint[0] * sin + snappedPoint[1] * cos
+      const worldX = buildingPosition[0] + planPoint[0] * cos + planPoint[1] * sin
+      const worldZ = buildingPosition[2] - planPoint[0] * sin + planPoint[1] * cos
 
       emitter.emit(`grid:${eventType}` as any, {
         nativeEvent: nativeEvent.nativeEvent as any,
         position: [worldX, floorplanGridWorldY, worldZ],
-        localPosition: [snappedPoint[0], floorplanGridLocalY, snappedPoint[1]],
+        localPosition: [planPoint[0], floorplanGridLocalY, planPoint[1]],
       })
-
-      return snappedPoint
     },
     [buildingPosition, buildingRotationY, floorplanGridLocalY, floorplanGridWorldY],
   )
@@ -8413,7 +8403,7 @@ export function FloorplanPanel({
       }
 
       if (referenceScaleDraft) {
-        emitFloorplanGridEvent('move', planPoint, event)
+        emitFloorplanGridEvent('move', getSnappedFloorplanPoint(planPoint), event)
 
         setCursorPoint((previousPoint) =>
           previousPoint && pointsEqual(previousPoint, planPoint) ? previousPoint : planPoint,
@@ -8430,21 +8420,24 @@ export function FloorplanPanel({
       }
 
       if (isCeilingBuildActive) {
-        // Polygon vertex: grid (snapToHalf) + optional 45° angle snap from
-        // the previous vertex. Wall magnetic snap may still win, while
+        const bypassSnap = shiftPressed || event.shiftKey
+        // Polygon vertex: grid (snapToHalf) or 15° angle snap from the
+        // previous vertex. Wall magnetic snap may still win, while
         // generic alignment runs only when angle snap is OFF (first vertex,
         // or Shift held) so it does not pull a locked angle sideways.
-        const angleSnap = ceilingDraftPoints.length > 0 && !shiftPressed
+        const angleSnap = ceilingDraftPoints.length > 0 && !bypassSnap
         const fallbackPoint = snapPolygonDraftPoint({
           point: planPoint,
           start: ceilingDraftPoints[ceilingDraftPoints.length - 1],
           angleSnap,
+          bypassSnap,
         })
         const snappedPoint = resolveCeilingPlanPointSnap({
           rawPoint: planPoint,
           fallbackPoint,
           levelId,
           altKey: event.altKey,
+          shiftKey: bypassSnap,
           align: !angleSnap,
         }).point
 
@@ -8456,8 +8449,11 @@ export function FloorplanPanel({
       }
 
       if (isRoofBuildActive) {
-        let snappedPoint = getSnappedFloorplanPoint(planPoint)
-        snappedPoint = alignFloorplanDraftPoint(snappedPoint, { bypass: event.altKey })
+        const bypassSnap = shiftPressed || event.shiftKey
+        let snappedPoint = bypassSnap ? planPoint : getSnappedFloorplanPoint(planPoint)
+        snappedPoint = alignFloorplanDraftPoint(snappedPoint, {
+          bypass: event.altKey || bypassSnap,
+        })
         emitFloorplanGridEvent('move', snappedPoint, event)
         setCursorPoint((previousPoint) =>
           previousPoint && pointsEqual(previousPoint, snappedPoint) ? previousPoint : snappedPoint,
@@ -8474,23 +8470,31 @@ export function FloorplanPanel({
       }
 
       if (isFenceBuildActive) {
+        const bypassSnap = shiftPressed || event.shiftKey
         // Fence draft: grid snap (+ existing-wall/fence endpoint snap), then
         // Figma alignment — same endpoint-wins precedence as the wall branch.
+        // While a draft is open the segment locks to 15° rays from its start
+        // unless Shift is held; Shift bypasses grid, magnetic, angle, and
+        // alignment snap.
+        const fenceAngleSnap = fenceDraftStart !== null && !bypassSnap
         const fenceSnapped = snapFenceDraftPoint({
           point: planPoint,
           walls,
           fences,
-          step: shiftPressed ? WALL_FINE_GRID_STEP : undefined,
+          start: fenceDraftStart ?? undefined,
+          angleSnap: fenceAngleSnap,
+          bypassSnap,
         })
-        const fenceGridBase = snapWallPointToGrid(
-          planPoint,
-          shiftPressed ? WALL_FINE_GRID_STEP : WALL_GRID_STEP,
-        )
+        const fenceGridBase = bypassSnap ? planPoint : snapWallPointToGrid(planPoint)
         const fenceLocked =
-          fenceSnapped[0] !== fenceGridBase[0] || fenceSnapped[1] !== fenceGridBase[1]
+          !bypassSnap &&
+          (fenceSnapped[0] !== fenceGridBase[0] || fenceSnapped[1] !== fenceGridBase[1])
         let snappedPoint = fenceSnapped
-        if (fenceLocked) useAlignmentGuides.getState().clear()
-        else snappedPoint = alignFloorplanDraftPoint(fenceSnapped, { bypass: event.altKey })
+        if (fenceLocked || fenceAngleSnap) useAlignmentGuides.getState().clear()
+        else
+          snappedPoint = alignFloorplanDraftPoint(fenceSnapped, {
+            bypass: event.altKey || bypassSnap,
+          })
 
         emitFloorplanGridEvent('move', snappedPoint, event)
         setCursorPoint((previousPoint) =>
@@ -8511,11 +8515,13 @@ export function FloorplanPanel({
       // the local polygon-draft state actually updates as the cursor
       // moves (the catch-all would otherwise swallow the move event).
       if (isPolygonBuildActive) {
-        const angleSnap = activePolygonDraftPoints.length > 0 && !shiftPressed
+        const bypassSnap = shiftPressed || event.shiftKey
+        const angleSnap = activePolygonDraftPoints.length > 0 && !bypassSnap
         const fallbackPoint = snapPolygonDraftPoint({
           point: planPoint,
           start: activePolygonDraftPoints[activePolygonDraftPoints.length - 1],
           angleSnap,
+          bypassSnap,
         })
         let snappedPoint = fallbackPoint
         if (isSlabBuildActive) {
@@ -8524,12 +8530,15 @@ export function FloorplanPanel({
             fallbackPoint,
             levelId,
             altKey: event.altKey,
+            shiftKey: bypassSnap,
             align: !angleSnap,
           }).point
         } else if (angleSnap) {
           useAlignmentGuides.getState().clear()
         } else {
-          snappedPoint = alignFloorplanDraftPoint(fallbackPoint, { bypass: event.altKey })
+          snappedPoint = alignFloorplanDraftPoint(fallbackPoint, {
+            bypass: event.altKey || bypassSnap,
+          })
         }
 
         // Emit `grid:move` so the registry-driven slab tool also tracks
@@ -8538,7 +8547,7 @@ export function FloorplanPanel({
 
         setCursorPoint((previousPoint) => {
           const hasChanged = !(previousPoint && pointsEqual(previousPoint, snappedPoint))
-          if (hasChanged && activePolygonDraftPoints.length > 0) {
+          if (!bypassSnap && hasChanged && activePolygonDraftPoints.length > 0) {
             sfxEmitter.emit('sfx:grid-snap')
           }
           return snappedPoint
@@ -8594,7 +8603,8 @@ export function FloorplanPanel({
       // routing through `grid:move`, which would otherwise be processed
       // by the floor strategy and drop the item to floor height.
       if (isCeilingItemPlacementActive) {
-        const snappedPoint = getSnappedFloorplanPoint(planPoint)
+        const bypassSnap = shiftPressed || event.shiftKey
+        const snappedPoint = bypassSnap ? planPoint : getSnappedFloorplanPoint(planPoint)
         setCursorPoint((previousPoint) =>
           previousPoint && pointsEqual(previousPoint, snappedPoint) ? previousPoint : snappedPoint,
         )
@@ -8608,7 +8618,8 @@ export function FloorplanPanel({
       // comment there). Wall build skips this so its own branch below
       // updates local `draftEnd` state alongside the registry tool.
       if (!isWallBuildActive && isFloorplanGridInteractionActive) {
-        const snappedPoint = emitFloorplanGridEvent('move', planPoint, event)
+        const snappedPoint = event.shiftKey ? planPoint : getSnappedFloorplanPoint(planPoint)
+        emitFloorplanGridEvent('move', snappedPoint, event)
         setCursorPoint((previousPoint) =>
           previousPoint && pointsEqual(previousPoint, snappedPoint) ? previousPoint : snappedPoint,
         )
@@ -8630,27 +8641,31 @@ export function FloorplanPanel({
         return
       }
 
-      // Wall draft: grid snap (orthogonal walls follow naturally from a
-      // grid-aligned start; Shift = fine 0.05m step), then Figma-style
-      // alignment layered on top. An existing wall endpoint / join snap
-      // wins outright — never pull the cursor off a corner the user is
-      // closing onto — so alignment runs ONLY when the wall snap left the
-      // point on the plain grid. Alt bypasses alignment.
+      // Wall draft: grid + magnetic snap, then Figma-style alignment.
+      // While a draft is open the segment locks to 15° rays from its
+      // start unless Shift is held. Shift bypasses grid, magnetic, angle,
+      // and alignment snap.
+      const bypassSnap = shiftPressed || event.shiftKey
+      const wallAngleSnap = draftStart !== null && !bypassSnap
       const wallSnap = snapWallDraftPointDetailed({
         point: planPoint,
         walls,
-        step: shiftPressed ? WALL_FINE_GRID_STEP : undefined,
-        magnetic: useEditor.getState().magneticSnap,
+        start: draftStart ?? undefined,
+        angleSnap: wallAngleSnap,
+        bypassSnap,
+        magnetic: !bypassSnap && useEditor.getState().magneticSnap,
       })
       const wallSnapped = wallSnap.point
       // Locked onto existing geometry (corner / midpoint / crossing / edge) →
       // that snap wins, so skip Figma alignment and stand the beacon there.
       const lockedToWall = wallSnap.snap !== null
       let snappedPoint = wallSnapped
-      if (lockedToWall) {
+      if (lockedToWall || wallAngleSnap) {
         useAlignmentGuides.getState().clear()
       } else {
-        snappedPoint = alignFloorplanDraftPoint(wallSnapped, { bypass: event.altKey })
+        snappedPoint = alignFloorplanDraftPoint(wallSnapped, {
+          bypass: event.altKey || bypassSnap,
+        })
       }
       useWallSnapIndicator
         .getState()
@@ -8668,9 +8683,8 @@ export function FloorplanPanel({
 
       setDraftEnd((previousEnd) => {
         if (
-          !previousEnd ||
-          previousEnd[0] !== snappedPoint[0] ||
-          previousEnd[1] !== snappedPoint[1]
+          !bypassSnap &&
+          (!previousEnd || previousEnd[0] !== snappedPoint[0] || previousEnd[1] !== snappedPoint[1])
         ) {
           sfxEmitter.emit('sfx:grid-snap')
         }
@@ -8874,17 +8888,10 @@ export function FloorplanPanel({
       // call. `emitFloorplanGridEvent('click', …)` in
       // `useFloorplanBackgroundPlacement` fires it synchronously
       // just before this callback runs, so by the time we get here
-      // the wall already exists in the scene.
-      //
-      // We still attempt the create as a fallback in case the 3D
-      // tool isn't mounted (unusual — both views are always
-      // mounted today, but defensive). When the wall already
-      // exists `createWallOnCurrentLevel` returns null via its
-      // duplicate-detection branch; we treat that as "the 3D side
-      // committed" and chain the draft state forward instead of
-      // clearing it (the previous behaviour caused the 2nd-segment
-      // draft to silently break after click 2).
-      const createdWall = createWallOnCurrentLevel(draftStart, point)
+      // the wall already exists in the scene. Committing here as
+      // well used to double-create walls whenever the two snap
+      // pipelines resolved endpoints ≥1e-6 apart (the duplicate
+      // check compares exact endpoints).
 
       // Alt commits a single wall: drop the draft so the next click
       // starts a fresh segment instead of chaining off this endpoint.
@@ -8895,9 +8902,10 @@ export function FloorplanPanel({
         return
       }
 
-      const nextStart: WallPlanPoint = createdWall
-        ? [createdWall.end[0], createdWall.end[1]]
-        : point
+      // Chain the next segment from the 3D tool's resolved commit
+      // point (it may have corner-snapped or split-adjusted the
+      // endpoint) so both views draft from the same start.
+      const nextStart: WallPlanPoint = useSegmentDraftChain.getState().wall ?? point
       setDraftStart(nextStart)
       setDraftEnd(nextStart)
       setCursorPoint(nextStart)
@@ -8930,6 +8938,7 @@ export function FloorplanPanel({
       walls: WallNode[]
       start?: WallPlanPoint
       angleSnap?: boolean
+      bypassSnap?: boolean
       step?: number
     }) => snapWallDraftPoint({ ...args, magnetic: useEditor.getState().magneticSnap }),
     [],
@@ -8939,6 +8948,7 @@ export function FloorplanPanel({
     ceilingDraftPoints,
     clearFencePlacementDraft,
     clearRoofPlacementDraft,
+    clearWallPlacementDraft,
     emitFloorplanGridEvent,
     fenceDraftStart,
     fences,
@@ -8994,7 +9004,7 @@ export function FloorplanPanel({
         event.preventDefault()
         event.stopPropagation()
 
-        emitFloorplanGridEvent('click', planPoint, event)
+        emitFloorplanGridEvent('click', getSnappedFloorplanPoint(planPoint), event)
 
         if (!referenceScaleDraft.start) {
           setReferenceScaleDraft({
@@ -9137,11 +9147,13 @@ export function FloorplanPanel({
         return
       }
 
-      const angleSnap = activePolygonDraftPoints.length > 0 && !shiftPressed
+      const bypassSnap = shiftPressed || event.shiftKey
+      const angleSnap = activePolygonDraftPoints.length > 0 && !bypassSnap
       const fallbackPoint = snapPolygonDraftPoint({
         point: planPoint,
         start: activePolygonDraftPoints[activePolygonDraftPoints.length - 1],
         angleSnap,
+        bypassSnap,
       })
 
       if (isCeilingBuildActive) {
@@ -9150,6 +9162,7 @@ export function FloorplanPanel({
           fallbackPoint,
           levelId,
           altKey: event.altKey,
+          shiftKey: bypassSnap,
           align: !angleSnap,
         }).point
         emitFloorplanGridEvent('double-click', snappedPoint, event)
@@ -9165,6 +9178,7 @@ export function FloorplanPanel({
           fallbackPoint,
           levelId,
           altKey: event.altKey,
+          shiftKey: bypassSnap,
           align: !angleSnap,
         }).point
         // Slab is registry-driven: forward the double-click so the 3D tool
diff --git a/packages/editor/src/components/editor/group-rotate-handle.tsx b/packages/editor/src/components/editor/group-rotate-handle.tsx
index 3d7c434e..9eef3772 100644
--- a/packages/editor/src/components/editor/group-rotate-handle.tsx
+++ b/packages/editor/src/components/editor/group-rotate-handle.tsx
@@ -3,6 +3,7 @@
 import {
   type AnyNode,
   type AnyNodeId,
+  DEFAULT_ANGLE_STEP,
   useLiveNodeOverrides,
   useLiveTransforms,
   useScene,
@@ -40,8 +41,6 @@ import {
   useInvisibleHitAreaMaterial,
 } from './node-arrow-handles'
 
-const ROTATE_SNAP = Math.PI / 12 // 15°
-
 /**
  * Group-rotate gizmo. When 2+ transformable nodes in the active level frame are
  * selected, a single rotation handle appears at the selection's bounding-box
@@ -201,7 +200,7 @@ function GroupRotateHandleInner({ ids }: { ids: string[] }) {
       let delta = angleOf(moveHit) - initialAngle
       while (delta > Math.PI) delta -= 2 * Math.PI
       while (delta < -Math.PI) delta += 2 * Math.PI
-      if (e.shiftKey) delta = Math.round(delta / ROTATE_SNAP) * ROTATE_SNAP
+      if (!e.shiftKey) delta = Math.round(delta / DEFAULT_ANGLE_STEP) * DEFAULT_ANGLE_STEP
 
       // Orbit each node's anchor point(s) CCW by `delta` (atan2 x→z sense) and
       // turn its yaw by `-delta` to match three.js Y-rotation handedness (same
diff --git a/packages/editor/src/components/editor/handles/use-handle-drag.ts b/packages/editor/src/components/editor/handles/use-handle-drag.ts
index 758bee54..e1b0ae86 100644
--- a/packages/editor/src/components/editor/handles/use-handle-drag.ts
+++ b/packages/editor/src/components/editor/handles/use-handle-drag.ts
@@ -11,7 +11,7 @@ import {
 import { useViewer } from '@pascal-app/viewer'
 import { type ThreeEvent, useThree } from '@react-three/fiber'
 import { useEffect, useRef } from 'react'
-import { type Camera, type Object3D, type Plane, Vector2, type Vector3 } from 'three'
+import { type Camera, type Object3D, type Plane, type Ray, Vector2, type Vector3 } from 'three'
 import { sfxEmitter } from '../../../lib/sfx-bus'
 import { suppressBoxSelectForPointer } from '../../tools/select/box-select-state'
 
@@ -27,9 +27,12 @@ type IntersectPlane = (
   target: Vector3,
 ) => Vector3 | null
 
+type GetPointerRay = (clientX: number, clientY: number, target: Ray) => Ray
+
 export type HandleDragStartContext = {
   event: ThreeEvent<PointerEvent>
   camera: Camera
+  getPointerRay: GetPointerRay
   intersectPlane: IntersectPlane
   initialNode: AnyNode
   node: AnyNode
@@ -40,6 +43,7 @@ export type HandleDragStartContext = {
 
 export type HandleDragMoveContext = {
   event: PointerEvent
+  getPointerRay: GetPointerRay
   intersectPlane: IntersectPlane
 }
 
@@ -121,13 +125,20 @@ export function useHandleDrag(args: UseHandleDragArgs) {
     rideObject.updateMatrixWorld()
 
     const ndc = new Vector2()
-    const intersectPlane: IntersectPlane = (clientX, clientY, plane, target) => {
+    const setPointerRay = (clientX: number, clientY: number) => {
       const rect = gl.domElement.getBoundingClientRect()
       ndc.set(
         ((clientX - rect.left) / rect.width) * 2 - 1,
         -((clientY - rect.top) / rect.height) * 2 + 1,
       )
       raycaster.setFromCamera(ndc, camera)
+    }
+    const getPointerRay: GetPointerRay = (clientX, clientY, target) => {
+      setPointerRay(clientX, clientY)
+      return target.copy(raycaster.ray)
+    }
+    const intersectPlane: IntersectPlane = (clientX, clientY, plane, target) => {
+      setPointerRay(clientX, clientY)
       return raycaster.ray.intersectPlane(plane, target)
     }
 
@@ -137,6 +148,7 @@ export function useHandleDrag(args: UseHandleDragArgs) {
     const session = args.onStart({
       event,
       camera,
+      getPointerRay,
       intersectPlane,
       initialNode,
       node,
@@ -159,7 +171,7 @@ export function useHandleDrag(args: UseHandleDragArgs) {
     let lastPatch: Partial<AnyNode> | null = null
 
     const onMove = (moveEvent: PointerEvent) => {
-      const patch = session.move({ event: moveEvent, intersectPlane })
+      const patch = session.move({ event: moveEvent, getPointerRay, intersectPlane })
       if (!patch) return
       lastPatch = patch
       useLiveNodeOverrides.getState().set(overrideId, patch as Record<string, unknown>)
diff --git a/packages/editor/src/components/editor/node-arrow-handles.tsx b/packages/editor/src/components/editor/node-arrow-handles.tsx
index a8538131..0ef913c5 100644
--- a/packages/editor/src/components/editor/node-arrow-handles.tsx
+++ b/packages/editor/src/components/editor/node-arrow-handles.tsx
@@ -6,6 +6,7 @@ import {
   type ArcResizeHandle,
   type Cursor,
   createSceneApi,
+  DEFAULT_ANGLE_STEP,
   type HandleDescriptor,
   type HandlePortal,
   type LinearResizeHandle,
@@ -34,6 +35,7 @@ import {
   OrthographicCamera,
   Plane,
   Quaternion,
+  Ray,
   RingGeometry,
   Vector3,
 } from 'three'
@@ -59,6 +61,43 @@ import { type HandleDragControls, useHandleDrag } from './handles/use-handle-dra
 // Pooled scratch for the handle rig's world-relative pose mapping.
 const _rigRelative = new Matrix4()
 const _rigScratchScale = new Vector3()
+const _resizeAxisW = new Vector3()
+const _resizeScale = new Vector3()
+const _resizeQuaternion = new Quaternion()
+const _resizeOriginW = new Vector3()
+const _resizePositionW = new Vector3()
+const _resizeRay = new Ray()
+const _resizeRayW = new Vector3()
+
+function axisVector(axis: 'x' | 'y' | 'z', target: Vector3) {
+  target.set(0, 0, 0)
+  if (axis === 'x') target.x = 1
+  else if (axis === 'y') target.y = 1
+  else target.z = 1
+  return target
+}
+
+function axisScale(axis: 'x' | 'y' | 'z', scale: Vector3) {
+  return axis === 'x' ? scale.x : axis === 'y' ? scale.y : scale.z
+}
+
+function closestAxisParameterToRay(axisOrigin: Vector3, axisDirection: Vector3, ray: Ray) {
+  _resizeRayW.subVectors(axisOrigin, ray.origin)
+  const b = axisDirection.dot(ray.direction)
+  const d = axisDirection.dot(_resizeRayW)
+  const e = ray.direction.dot(_resizeRayW)
+  const denominator = 1 - b * b
+  if (Math.abs(denominator) < 1e-6) {
+    return -d
+  }
+
+  const axisParameter = (b * e - d) / denominator
+  const rayParameter = e + b * axisParameter
+  if (rayParameter < 0) {
+    return -d
+  }
+  return axisParameter
+}
 
 export {
   ARROW_COLOR,
@@ -579,34 +618,31 @@ function LinearArrow({
     rideObject,
     setIsDragging,
     onStart: ({
-      camera: dragCamera,
       event,
+      getPointerRay,
       initialNode,
-      intersectPlane,
       nodeId,
       rideObject: dragRideObject,
       sceneApi,
     }) => {
-      const initialFrameInverse = new Matrix4().copy(dragRideObject.matrixWorld).invert()
-      const worldOrigin = new Vector3(...position).applyMatrix4(dragRideObject.matrixWorld)
-      const planeNormal = new Vector3().subVectors(dragCamera.position, worldOrigin).setY(0)
-      if (planeNormal.lengthSq() === 0) return null
-      planeNormal.normalize()
-      const plane = new Plane().setFromNormalAndCoplanarPoint(planeNormal, worldOrigin)
+      dragRideObject.matrixWorld.decompose(_resizePositionW, _resizeQuaternion, _resizeScale)
+      _resizeOriginW.set(...position).applyMatrix4(dragRideObject.matrixWorld)
+      axisVector(descriptor.axis, _resizeAxisW).applyQuaternion(_resizeQuaternion).normalize()
+      const localToWorldScale = axisScale(descriptor.axis, _resizeScale)
+      if (Math.abs(localToWorldScale) < 1e-6 || _resizeAxisW.lengthSq() === 0) return null
 
-      const hitWorld = new Vector3()
-      if (!intersectPlane(event.nativeEvent.clientX, event.nativeEvent.clientY, plane, hitWorld)) {
-        return null
-      }
-      const hitLocal = hitWorld.clone().applyMatrix4(initialFrameInverse)
+      const initialPointer =
+        closestAxisParameterToRay(
+          _resizeOriginW,
+          _resizeAxisW,
+          getPointerRay(event.nativeEvent.clientX, event.nativeEvent.clientY, _resizeRay),
+        ) / localToWorldScale
 
       const overrideId =
         (descriptor.kind === 'linear-resize'
           ? descriptor.overrideTarget?.(initialNode as never, sceneApi)
           : undefined) ?? nodeId
       const initialValue = descriptor.currentValue(initialNode)
-      const initialPointer =
-        descriptor.axis === 'x' ? hitLocal.x : descriptor.axis === 'y' ? hitLocal.y : hitLocal.z
       const minBound = resolveBound(descriptor.min, Number.NEGATIVE_INFINITY, initialNode, sceneApi)
       const maxBound = resolveBound(descriptor.max, Number.POSITIVE_INFINITY, initialNode, sceneApi)
       const gridSnapStep =
@@ -634,22 +670,19 @@ function LinearArrow({
             useEditor.getState().setActiveHandleDrag(null)
           }
         },
-        move: ({ event: moveEvent, intersectPlane: intersectMovePlane }) => {
-          const intersection = new Vector3()
-          if (!intersectMovePlane(moveEvent.clientX, moveEvent.clientY, plane, intersection)) {
-            return null
-          }
-          const intersectionLocal = intersection.clone().applyMatrix4(initialFrameInverse)
+        move: ({ event: moveEvent, getPointerRay: getMovePointerRay }) => {
           const currentPointer =
-            descriptor.axis === 'x'
-              ? intersectionLocal.x
-              : descriptor.axis === 'y'
-                ? intersectionLocal.y
-                : intersectionLocal.z
+            closestAxisParameterToRay(
+              _resizeOriginW,
+              _resizeAxisW,
+              getMovePointerRay(moveEvent.clientX, moveEvent.clientY, _resizeRay),
+            ) / localToWorldScale
           const delta = currentPointer - initialPointer
           const rawNext = initialValue + delta * factor
           const snappedNext =
-            gridSnapStep && gridSnapStep > 0 ? snapScalar(rawNext, gridSnapStep) : rawNext
+            !moveEvent.shiftKey && gridSnapStep && gridSnapStep > 0
+              ? snapScalar(rawNext, gridSnapStep)
+              : rawNext
           const next = Math.min(maxBound, Math.max(minBound, snappedNext))
           return descriptor.apply(initialNode as never, next, sceneApi) as Partial<AnyNode>
         },
@@ -1096,9 +1129,8 @@ function ArcArrow({
           while (delta > Math.PI) delta -= 2 * Math.PI
           while (delta < -Math.PI) delta += 2 * Math.PI
 
-          if (moveEvent.shiftKey && descriptor.shape === 'rotate') {
-            const step = Math.PI / 12
-            delta = Math.round(delta / step) * step
+          if (!moveEvent.shiftKey && descriptor.shape === 'rotate') {
+            delta = Math.round(delta / DEFAULT_ANGLE_STEP) * DEFAULT_ANGLE_STEP
           }
 
           if (isRotateShape && !isNodeNormalRot) {
diff --git a/packages/editor/src/components/editor/thumbnail-generator.tsx b/packages/editor/src/components/editor/thumbnail-generator.tsx
index e81cde62..72929e3f 100644
--- a/packages/editor/src/components/editor/thumbnail-generator.tsx
+++ b/packages/editor/src/components/editor/thumbnail-generator.tsx
@@ -202,12 +202,14 @@ export const ThumbnailGenerator = ({ onThumbnailCapture }: ThumbnailGeneratorPro
           restoreLevels = snapLevelsToTruePositions()
         }
 
-        // Hide scan and guide nodes directly so they are excluded from the
-        // thumbnail regardless of whether ScanSystem/GuideSystem listeners are
-        // registered. Returns a function that restores the original visibility.
+        // Hide scan, guide, and spawn nodes directly so they are excluded from
+        // the thumbnail regardless of whether ScanSystem/GuideSystem listeners
+        // are registered. Spawn renders on SCENE_LAYER for occlusion, so the
+        // thumbnail camera's layer mask can't filter it either. Returns a
+        // function that restores the original visibility.
         const restoreNodeVisibility = (() => {
           const saved = new Map<THREE.Object3D, boolean>()
-          for (const type of ['scan', 'guide'] as const) {
+          for (const type of ['scan', 'guide', 'spawn'] as const) {
             const ids = sceneRegistry.byType[type]!
             ids.forEach((id) => {
               const node = sceneRegistry.nodes.get(id)
@@ -238,18 +240,21 @@ export const ThumbnailGenerator = ({ onThumbnailCapture }: ThumbnailGeneratorPro
 
           // Notify other systems (wall cutouts, selection manager) to restore
           // their overrides before capture and re-apply them after.
-          emitter.emit('thumbnail:before-capture', undefined)
-          ;(renderer as any).setClearAlpha(0)
-          renderer.setRenderTarget(rt)
-          pipelineRef.current.render()
-          renderer.setRenderTarget(null)
-          emitter.emit('thumbnail:after-capture', undefined)
-
-          // Restore level positions, levelMode, and node visibility immediately after the
-          // render — before the async GPU readback.
-          restoreLevels()
-          restoreLevelMode?.()
-          restoreNodeVisibility()
+          try {
+            emitter.emit('thumbnail:before-capture', undefined)
+            ;(renderer as any).setClearAlpha(0)
+            renderer.setRenderTarget(rt)
+            pipelineRef.current.render()
+          } finally {
+            // Restore level positions, levelMode, and node visibility immediately
+            // after the render — before the async GPU readback. Runs in `finally`
+            // so a render failure can't leave helpers permanently hidden.
+            renderer.setRenderTarget(null)
+            emitter.emit('thumbnail:after-capture', undefined)
+            restoreLevels()
+            restoreLevelMode?.()
+            restoreNodeVisibility()
+          }
 
           // Read pixels from the RT asynchronously.
           // WebGPU copyTextureToBuffer aligns each row to 256 bytes, so we must
@@ -364,12 +369,15 @@ export const ThumbnailGenerator = ({ onThumbnailCapture }: ThumbnailGeneratorPro
           cameraData.resolution = { w: outW, h: outH }
         } else {
           // Fallback: plain render directly to the canvas
-          emitter.emit('thumbnail:before-capture', undefined)
-          gl.render(scene, thumbnailCamera)
-          emitter.emit('thumbnail:after-capture', undefined)
-          restoreLevels()
-          restoreLevelMode?.()
-          restoreNodeVisibility()
+          try {
+            emitter.emit('thumbnail:before-capture', undefined)
+            gl.render(scene, thumbnailCamera)
+          } finally {
+            emitter.emit('thumbnail:after-capture', undefined)
+            restoreLevels()
+            restoreLevelMode?.()
+            restoreNodeVisibility()
+          }
 
           let outW: number
           let outH: number
diff --git a/packages/editor/src/components/editor/use-floorplan-background-placement.ts b/packages/editor/src/components/editor/use-floorplan-background-placement.ts
index 4293df6c..387558c1 100644
--- a/packages/editor/src/components/editor/use-floorplan-background-placement.ts
+++ b/packages/editor/src/components/editor/use-floorplan-background-placement.ts
@@ -5,23 +5,21 @@ import { type MouseEvent as ReactMouseEvent, useCallback } from 'react'
 import { resolveCeilingPlanPointSnap } from '../../lib/ceiling-plan-snap'
 import { alignFloorplanDraftPoint, getPlanPointDistance } from '../../lib/floorplan'
 import { resolveSlabPlanPointSnap } from '../../lib/slab-plan-snap'
+import useSegmentDraftChain from '../../store/use-segment-draft-chain'
 import { snapFenceDraftPoint } from '../tools/fence/fence-drafting'
-import {
-  WALL_FINE_GRID_STEP,
-  WALL_GRID_STEP,
-  type WallPlanPoint,
-} from '../tools/wall/wall-drafting'
+import { WALL_GRID_STEP, type WallPlanPoint } from '../tools/wall/wall-drafting'
 
 type UseFloorplanBackgroundPlacementArgs = {
   activePolygonDraftPoints: WallPlanPoint[]
   ceilingDraftPoints: WallPlanPoint[]
   clearFencePlacementDraft: () => void
   clearRoofPlacementDraft: () => void
+  clearWallPlacementDraft: () => void
   emitFloorplanGridEvent: (
     type: 'click' | 'double-click' | 'move',
     planPoint: WallPlanPoint,
     event: ReactMouseEvent<SVGSVGElement>,
-  ) => WallPlanPoint
+  ) => void
   fenceDraftStart: WallPlanPoint | null
   fences: FenceNode[]
   findClosestWallPoint: (
@@ -67,6 +65,7 @@ type UseFloorplanBackgroundPlacementArgs = {
     walls: WallNode[]
     start?: WallPlanPoint
     angleSnap?: boolean
+    bypassSnap?: boolean
     step?: number
     gridSnap?: (point: WallPlanPoint) => WallPlanPoint
   }) => WallPlanPoint
@@ -74,6 +73,7 @@ type UseFloorplanBackgroundPlacementArgs = {
     point: WallPlanPoint
     start?: WallPlanPoint
     angleSnap: boolean
+    bypassSnap?: boolean
   }) => WallPlanPoint
   toPoint2D: (point: WallPlanPoint) => { x: number; y: number }
   walls: WallNode[]
@@ -81,7 +81,7 @@ type UseFloorplanBackgroundPlacementArgs = {
    * Snap a building-local plan point to the world XZ grid at `step`.
    * Injected so the hook doesn't have to know the building's rotation
    * or position — used by wall / fence branches that snap at variable
-   * step (Shift = fine).
+   * step.
    */
   worldGridSnap: (point: WallPlanPoint, step: number) => WallPlanPoint
 }
@@ -91,6 +91,7 @@ export function useFloorplanBackgroundPlacement({
   ceilingDraftPoints,
   clearFencePlacementDraft,
   clearRoofPlacementDraft,
+  clearWallPlacementDraft,
   emitFloorplanGridEvent,
   fenceDraftStart,
   fences,
@@ -154,21 +155,24 @@ export function useFloorplanBackgroundPlacement({
       }
 
       if (isCeilingBuildActive) {
+        const bypassSnap = shiftPressed || event.shiftKey
         // Align the committed vertex the same way the move-preview did, so
         // the placed point matches what the user saw. Wall magnetic snap may
         // still win; generic alignment is skipped when angle snap owns the
         // vertex (matches the move branch).
-        const angleSnap = ceilingDraftPoints.length > 0 && !shiftPressed
+        const angleSnap = ceilingDraftPoints.length > 0 && !bypassSnap
         const fallbackPoint = snapPolygonDraftPoint({
           point: planPoint,
           start: ceilingDraftPoints[ceilingDraftPoints.length - 1],
           angleSnap,
+          bypassSnap,
         })
         const snappedPoint = resolveCeilingPlanPointSnap({
           rawPoint: planPoint,
           fallbackPoint,
           levelId,
           altKey: event.altKey,
+          shiftKey: bypassSnap,
           align: !angleSnap,
         }).point
 
@@ -178,9 +182,11 @@ export function useFloorplanBackgroundPlacement({
       }
 
       if (isRoofBuildActive) {
-        const snappedPoint = alignFloorplanDraftPoint(getSnappedFloorplanPoint(planPoint), {
-          bypass: event.altKey,
-        })
+        const bypassSnap = shiftPressed || event.shiftKey
+        const snappedPoint = alignFloorplanDraftPoint(
+          bypassSnap ? planPoint : getSnappedFloorplanPoint(planPoint),
+          { bypass: event.altKey || bypassSnap },
+        )
         emitFloorplanGridEvent('click', snappedPoint, event)
         setCursorPoint(snappedPoint)
 
@@ -194,35 +200,57 @@ export function useFloorplanBackgroundPlacement({
       }
 
       if (isFenceBuildActive) {
+        const bypassSnap = shiftPressed || event.shiftKey
         // Fence draft: grid snap (+ existing-wall/fence endpoint snap), then
         // Figma alignment — endpoint snap wins (same precedence as move).
-        // `gridSnap` keeps the snap on the world XZ grid even when the
-        // building is rotated.
-        const fenceStep = shiftPressed ? WALL_FINE_GRID_STEP : WALL_GRID_STEP
+        // While a draft is open the segment locks to 15° rays from its
+        // start unless Shift is held; Shift bypasses grid, magnetic,
+        // angle, and alignment snap. `gridSnap` keeps the regular snap
+        // on the world XZ grid even when the building is rotated.
+        const fenceStep = WALL_GRID_STEP
+        const fenceAngleSnap = fenceDraftStart !== null && !bypassSnap
         const fenceSnapped = snapFenceDraftPoint({
           point: planPoint,
           walls,
           fences,
-          step: shiftPressed ? WALL_FINE_GRID_STEP : undefined,
+          start: fenceDraftStart ?? undefined,
+          angleSnap: fenceAngleSnap,
+          bypassSnap,
           gridSnap: (p) => worldGridSnap(p, fenceStep),
         })
-        const fenceGridBase = worldGridSnap(planPoint, fenceStep)
+        const fenceGridBase = bypassSnap ? planPoint : worldGridSnap(planPoint, fenceStep)
         const fenceLocked =
-          fenceSnapped[0] !== fenceGridBase[0] || fenceSnapped[1] !== fenceGridBase[1]
-        const snappedPoint = fenceLocked
-          ? fenceSnapped
-          : alignFloorplanDraftPoint(fenceSnapped, { bypass: event.altKey })
+          !bypassSnap &&
+          (fenceSnapped[0] !== fenceGridBase[0] || fenceSnapped[1] !== fenceGridBase[1])
+        const snappedPoint =
+          fenceLocked || fenceAngleSnap
+            ? fenceSnapped
+            : alignFloorplanDraftPoint(fenceSnapped, { bypass: event.altKey || bypassSnap })
 
         emitFloorplanGridEvent('click', snappedPoint, event)
         setCursorPoint(snappedPoint)
 
+        // Double-click finishes the chain. The emit above already made the
+        // 3D fence tool stopDrafting (its detail >= 2 guard), so close the
+        // 2D draft too — leaving it open desyncs the two views.
+        if (fenceDraftStart && event.detail >= 2) {
+          clearFencePlacementDraft()
+          return true
+        }
+
         if (!fenceDraftStart) {
           setFenceDraftStart(snappedPoint)
           setFenceDraftEnd(snappedPoint)
         } else if (
           getPlanPointDistance(toPoint2D(fenceDraftStart), toPoint2D(snappedPoint)) >= 0.01
         ) {
-          clearFencePlacementDraft()
+          // The 3D fence tool owns creation and keeps chaining from the
+          // committed fence's resolved end — chain the 2D draft from the
+          // same published point so both views draft the next segment
+          // from the same start.
+          const nextStart = useSegmentDraftChain.getState().fence ?? snappedPoint
+          setFenceDraftStart(nextStart)
+          setFenceDraftEnd(nextStart)
         } else {
           setFenceDraftEnd(snappedPoint)
         }
@@ -235,11 +263,13 @@ export function useFloorplanBackgroundPlacement({
       // swallow the click and skip local draft state updates — leaving
       // the 2D draft polygon invisible while the 3D tool builds fine).
       if (isPolygonBuildActive) {
-        const angleSnap = activePolygonDraftPoints.length > 0 && !shiftPressed
+        const bypassSnap = shiftPressed || event.shiftKey
+        const angleSnap = activePolygonDraftPoints.length > 0 && !bypassSnap
         const fallbackPoint = snapPolygonDraftPoint({
           point: planPoint,
           start: activePolygonDraftPoints[activePolygonDraftPoints.length - 1],
           angleSnap,
+          bypassSnap,
         })
         let snappedPoint = fallbackPoint
         if (isSlabBuildActive) {
@@ -248,10 +278,13 @@ export function useFloorplanBackgroundPlacement({
             fallbackPoint,
             levelId,
             altKey: event.altKey,
+            shiftKey: bypassSnap,
             align: !angleSnap,
           }).point
         } else if (!angleSnap) {
-          snappedPoint = alignFloorplanDraftPoint(fallbackPoint, { bypass: event.altKey })
+          snappedPoint = alignFloorplanDraftPoint(fallbackPoint, {
+            bypass: event.altKey || bypassSnap,
+          })
         }
 
         // Emit the grid event so the registry-driven slab tool also
@@ -275,25 +308,44 @@ export function useFloorplanBackgroundPlacement({
       // / draftEnd state in the floor plan would never update, leaving
       // the dashed-line draft preview invisible.
       if (isWallBuildActive) {
+        const bypassSnap = shiftPressed || event.shiftKey
         // Wall draft: grid snap (+ existing-wall endpoint/join snap), then
         // Figma alignment — endpoint/join snap wins (same precedence as the
         // move-preview branch), so committing onto a corner still works.
-        // `gridSnap` keeps the snap on the world XZ grid even when the
-        // building is rotated.
-        const wallStep = shiftPressed ? WALL_FINE_GRID_STEP : WALL_GRID_STEP
+        // While a draft is open the segment locks to 15° rays from its
+        // start unless Shift is held; Shift bypasses grid, magnetic,
+        // angle, and alignment snap. `gridSnap` keeps the regular snap
+        // on the world XZ grid even when the building is rotated.
+        const wallStep = WALL_GRID_STEP
+        const wallAngleSnap = draftStart !== null && !bypassSnap
         const wallSnapped = snapWallDraftPoint({
           point: planPoint,
           walls,
-          step: shiftPressed ? WALL_FINE_GRID_STEP : undefined,
+          start: draftStart ?? undefined,
+          angleSnap: wallAngleSnap,
+          bypassSnap,
           gridSnap: (p) => worldGridSnap(p, wallStep),
         })
-        const wallGridBase = worldGridSnap(planPoint, wallStep)
-        const wallLocked = wallSnapped[0] !== wallGridBase[0] || wallSnapped[1] !== wallGridBase[1]
-        const snappedPoint = wallLocked
-          ? wallSnapped
-          : alignFloorplanDraftPoint(wallSnapped, { bypass: false })
+        const wallGridBase = bypassSnap ? planPoint : worldGridSnap(planPoint, wallStep)
+        const wallLocked =
+          !bypassSnap && (wallSnapped[0] !== wallGridBase[0] || wallSnapped[1] !== wallGridBase[1])
+        const snappedPoint =
+          wallLocked || wallAngleSnap
+            ? wallSnapped
+            : alignFloorplanDraftPoint(wallSnapped, { bypass: event.altKey || bypassSnap })
 
         emitFloorplanGridEvent('click', snappedPoint, event)
+
+        // Double-click finishes the chain. The emit above already made the
+        // 3D wall tool stopDrafting (its detail >= 2 guard), so close the
+        // 2D draft too — otherwise it stays open against a closed 3D tool
+        // and the next previewed segment is silently never created.
+        if (draftStart && event.detail >= 2) {
+          clearWallPlacementDraft()
+          setCursorPoint(snappedPoint)
+          return true
+        }
+
         handleWallPlacementPoint(snappedPoint, { singleWall: event.altKey })
         return true
       }
@@ -311,7 +363,8 @@ export function useFloorplanBackgroundPlacement({
       // local floor-plan draft handler (column / spawn / shelf / etc.).
       // The tool's `grid:click` subscriber owns the placement.
       if (isFloorplanGridInteractionActive) {
-        const snappedPoint = emitFloorplanGridEvent('click', planPoint, event)
+        const snappedPoint = event.shiftKey ? planPoint : getSnappedFloorplanPoint(planPoint)
+        emitFloorplanGridEvent('click', snappedPoint, event)
         setCursorPoint(snappedPoint)
         return true
       }
@@ -323,6 +376,7 @@ export function useFloorplanBackgroundPlacement({
       ceilingDraftPoints,
       clearFencePlacementDraft,
       clearRoofPlacementDraft,
+      clearWallPlacementDraft,
       emitFloorplanGridEvent,
       fenceDraftStart,
       fences,
diff --git a/packages/editor/src/components/systems/ceiling/ceiling-selection-affordance-system.tsx b/packages/editor/src/components/systems/ceiling/ceiling-selection-affordance-system.tsx
index c45fb78d..ac7353ee 100644
--- a/packages/editor/src/components/systems/ceiling/ceiling-selection-affordance-system.tsx
+++ b/packages/editor/src/components/systems/ceiling/ceiling-selection-affordance-system.tsx
@@ -11,7 +11,7 @@ import {
 import { useViewer } from '@pascal-app/viewer'
 import { createPortal, type ThreeEvent, useThree } from '@react-three/fiber'
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
-import { BoxGeometry, type Object3D, Plane, Raycaster, Vector2, Vector3 } from 'three'
+import { BoxGeometry, type Group, type Object3D, Plane, Raycaster, Vector2, Vector3 } from 'three'
 import { useShallow } from 'zustand/react/shallow'
 import {
   clearCeilingSnapFeedback,
@@ -153,6 +153,7 @@ const CeilingSelectionAffordance = ({
   const [draggedCornerIndex, setDraggedCornerIndex] = useState<number | null>(null)
   const [previewPolygon, setPreviewPolygon] = useState<Array<[number, number]> | null>(null)
   const dragRef = useRef<CornerDragState | null>(null)
+  const bracketsRootRef = useRef<Group>(null)
   const raycasterRef = useRef(new Raycaster())
   const ndcRef = useRef(new Vector2())
   const planeRef = useRef(new Plane())
@@ -293,19 +294,23 @@ const CeilingSelectionAffordance = ({
         initialCorner[0] + (planePosition[0] - drag.startPlanePosition[0]),
         initialCorner[1] + (planePosition[1] - drag.startPlanePosition[1]),
       ]
-      const gridNextPosition: [number, number] = [
-        initialCorner[0] + snapToHalf(planePosition[0] - drag.startPlanePosition[0]),
-        initialCorner[1] + snapToHalf(planePosition[1] - drag.startPlanePosition[1]),
-      ]
+      const gridNextPosition: [number, number] = event.shiftKey
+        ? rawNextPosition
+        : [
+            initialCorner[0] + snapToHalf(planePosition[0] - drag.startPlanePosition[0]),
+            initialCorner[1] + snapToHalf(planePosition[1] - drag.startPlanePosition[1]),
+          ]
       const nextPosition = resolveCeilingPlanPointSnap({
         rawPoint: rawNextPosition,
         fallbackPoint: gridNextPosition,
         levelId,
         excludeId: drag.ceilingId,
         altKey: event.altKey,
+        shiftKey: event.shiftKey,
       }).point
 
       if (
+        !event.shiftKey &&
         drag.previousSnappedPosition &&
         (nextPosition[0] !== drag.previousSnappedPosition[0] ||
           nextPosition[1] !== drag.previousSnappedPosition[1])
@@ -372,6 +377,25 @@ const CeilingSelectionAffordance = ({
     }
   }, [effectiveCeiling.id, getHandlePlanePoint, levelId, selectCeilingForEdit])
 
+  // The brackets render on SCENE_LAYER (scene-depth occlusion), so unlike
+  // EDITOR_LAYER affordances the thumbnail camera can't filter them — hide
+  // them around captures via synchronous Object3D.visible mutation (the
+  // capture renders right after the emit), same as `site-boundary-editor.tsx`.
+  useEffect(() => {
+    const hideForCapture = () => {
+      if (bracketsRootRef.current) bracketsRootRef.current.visible = false
+    }
+    const restoreAfterCapture = () => {
+      if (bracketsRootRef.current) bracketsRootRef.current.visible = true
+    }
+    emitter.on('thumbnail:before-capture', hideForCapture)
+    emitter.on('thumbnail:after-capture', restoreAfterCapture)
+    return () => {
+      emitter.off('thumbnail:before-capture', hideForCapture)
+      emitter.off('thumbnail:after-capture', restoreAfterCapture)
+    }
+  }, [])
+
   useEffect(() => {
     let frameId = 0
 
@@ -401,7 +425,10 @@ const CeilingSelectionAffordance = ({
   if (!levelObject || corners.length === 0) return null
 
   return createPortal(
-    <group position={[0, (effectiveCeiling.height ?? 2.5) + BRACKET_Y_OFFSET, 0]}>
+    <group
+      position={[0, (effectiveCeiling.height ?? 2.5) + BRACKET_Y_OFFSET, 0]}
+      ref={bracketsRootRef}
+    >
       {corners.map((corner, index) => (
         <CornerBracket
           ceiling={effectiveCeiling}
diff --git a/packages/editor/src/components/systems/roof/roof-edit-system.tsx b/packages/editor/src/components/systems/roof/roof-edit-system.tsx
index 3b186742..f80c022f 100644
--- a/packages/editor/src/components/systems/roof/roof-edit-system.tsx
+++ b/packages/editor/src/components/systems/roof/roof-edit-system.tsx
@@ -20,6 +20,7 @@ function makeEmptySegmentGeometry(): THREE.BufferGeometry {
   g.setAttribute('position', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
   g.setAttribute('normal', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
   g.setAttribute('uv', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
+  g.setAttribute('uv2', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
   // Match the four material slots the roof-segment renderer's material
   // array expects (0=top, 1=side, 2=interior, 3=shingle). Without these
   // groups, mesh.material is a single-material lookup that mismatches
diff --git a/packages/editor/src/components/tools/elevator/elevator-tool.tsx b/packages/editor/src/components/tools/elevator/elevator-tool.tsx
index 3a1db9b2..d7cb941c 100644
--- a/packages/editor/src/components/tools/elevator/elevator-tool.tsx
+++ b/packages/editor/src/components/tools/elevator/elevator-tool.tsx
@@ -195,12 +195,13 @@ export const ElevatorTool: React.FC<ElevatorToolProps> = ({ buildingId, levelId,
     }
 
     const onGridMove = (event: GridEvent) => {
+      const bypassSnap = event.nativeEvent?.shiftKey === true
       const [gridX, gridZ] = alignPoint(
-        Math.round(event.localPosition[0] * 2) / 2,
-        Math.round(event.localPosition[2] * 2) / 2,
+        bypassSnap ? event.localPosition[0] : Math.round(event.localPosition[0] * 2) / 2,
+        bypassSnap ? event.localPosition[2] : Math.round(event.localPosition[2] * 2) / 2,
         event.localPosition[0],
         event.localPosition[2],
-        event.nativeEvent?.altKey === true,
+        event.nativeEvent?.altKey === true || bypassSnap,
       )
       const supportY = resolveElevatorSupportY({
         buildingId: currentBuildingId,
@@ -220,6 +221,7 @@ export const ElevatorTool: React.FC<ElevatorToolProps> = ({ buildingId, levelId,
       })
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (gridX !== previousGridPosRef.current[0] || gridZ !== previousGridPosRef.current[1])
       ) {
@@ -237,12 +239,13 @@ export const ElevatorTool: React.FC<ElevatorToolProps> = ({ buildingId, levelId,
       })
       if (!latestBuildingId) return
 
+      const bypassSnap = event.nativeEvent?.shiftKey === true
       const [gridX, gridZ] = alignPoint(
-        Math.round(event.localPosition[0] * 2) / 2,
-        Math.round(event.localPosition[2] * 2) / 2,
+        bypassSnap ? event.localPosition[0] : Math.round(event.localPosition[0] * 2) / 2,
+        bypassSnap ? event.localPosition[2] : Math.round(event.localPosition[2] * 2) / 2,
         event.localPosition[0],
         event.localPosition[2],
-        event.nativeEvent?.altKey === true,
+        event.nativeEvent?.altKey === true || bypassSnap,
       )
       commitElevatorPlacement(
         latestBuildingId,
diff --git a/packages/editor/src/components/tools/elevator/move-elevator-tool.tsx b/packages/editor/src/components/tools/elevator/move-elevator-tool.tsx
index f98004fa..10a2b201 100644
--- a/packages/editor/src/components/tools/elevator/move-elevator-tool.tsx
+++ b/packages/editor/src/components/tools/elevator/move-elevator-tool.tsx
@@ -131,8 +131,9 @@ export function MoveElevatorTool({
     }
 
     const onGridMove = (event: GridEvent) => {
-      const rawX = Math.round(event.localPosition[0] * 2) / 2
-      const rawZ = Math.round(event.localPosition[2] * 2) / 2
+      const bypassSnap = event.nativeEvent?.shiftKey === true
+      const rawX = bypassSnap ? event.localPosition[0] : Math.round(event.localPosition[0] * 2) / 2
+      const rawZ = bypassSnap ? event.localPosition[2] : Math.round(event.localPosition[2] * 2) / 2
       const anchor = dragAnchorRef.current ?? [rawX, rawZ]
       dragAnchorRef.current = anchor
       const gridX = movingNode.position[0] + (rawX - anchor[0])
@@ -145,6 +146,7 @@ export function MoveElevatorTool({
       })
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (gridX !== previousGridPosRef.current[0] || gridZ !== previousGridPosRef.current[1])
       ) {
diff --git a/packages/editor/src/components/tools/fence/fence-drafting.ts b/packages/editor/src/components/tools/fence/fence-drafting.ts
index 5ea60acb..f7dc1f92 100644
--- a/packages/editor/src/components/tools/fence/fence-drafting.ts
+++ b/packages/editor/src/components/tools/fence/fence-drafting.ts
@@ -1,8 +1,10 @@
 import {
+  DEFAULT_ANGLE_STEP,
   FenceNode,
   getWallCurveFrameAt,
   getWallCurveLength,
   isCurvedWall,
+  snapPointAlongAngleRay,
   useScene,
   type WallNode,
 } from '@pascal-app/core'
@@ -12,9 +14,7 @@ import useEditor from '../../../store/use-editor'
 import {
   findWallSnapTarget,
   getSegmentGridStep,
-  getWallAngleSnapStep,
   isSegmentLongEnough,
-  snapPointTo45Degrees,
   snapPointToGrid,
   type WallPlanPoint,
 } from '../wall/wall-drafting'
@@ -132,7 +132,9 @@ export function snapFenceDraftPoint(args: {
   start?: FencePlanPoint
   angleSnap?: boolean
   ignoreFenceIds?: string[]
-  /** Override the grid step (e.g. `WALL_FINE_GRID_STEP` for precision mode). */
+  bypassSnap?: boolean
+  magnetic?: boolean
+  /** Override the grid step. */
   step?: number
   /**
    * Optional grid-snap function. When provided, replaces the default
@@ -142,17 +144,45 @@ export function snapFenceDraftPoint(args: {
    */
   gridSnap?: (point: FencePlanPoint) => FencePlanPoint
 }): FencePlanPoint {
-  const { point, walls, fences, start, angleSnap = false, ignoreFenceIds, step, gridSnap } = args
+  const {
+    point,
+    walls,
+    fences,
+    start,
+    angleSnap = false,
+    ignoreFenceIds,
+    bypassSnap = false,
+    magnetic = true,
+    step,
+    gridSnap,
+  } = args
+  if (bypassSnap) return point
+
   const gridStep = step ?? getSegmentGridStep()
-  const angleStep = getWallAngleSnapStep(gridStep)
-  const basePoint =
+
+  // Magnetic endpoint snap must beat the angle lock, and the lock can pull
+  // the cursor far enough off an endpoint that probing the locked point
+  // would never engage — so under the lock, probe from the RAW cursor
+  // first (mirrors `snapWallDraftPointDetailed`'s special-point pre-pass).
+  if (start && angleSnap) {
+    const rawTarget =
+      magnetic &&
+      (findFenceSnapTarget(point, fences, ignoreFenceIds) ?? findWallSnapTarget(point, walls))
+    if (rawTarget) return rawTarget
+  }
+
+  // The angle path snaps the distance ALONG the 15° ray — a scalar, the
+  // same in world and local frames — so the `gridSnap` world-grid override
+  // only applies when the angle lock is off.
+  const basePoint: FencePlanPoint =
     start && angleSnap
-      ? snapPointTo45Degrees(start, point, gridStep, angleStep, gridSnap)
+      ? [...snapPointAlongAngleRay(start, point, DEFAULT_ANGLE_STEP, gridStep)]
       : gridSnap
         ? gridSnap(point)
         : snapPointToGrid(point, gridStep)
-  const fenceSnapTarget = findFenceSnapTarget(basePoint, fences, ignoreFenceIds)
+  if (!magnetic) return basePoint
 
+  const fenceSnapTarget = findFenceSnapTarget(basePoint, fences, ignoreFenceIds)
   return fenceSnapTarget ?? findWallSnapTarget(basePoint, walls) ?? basePoint
 }
 
diff --git a/packages/editor/src/components/tools/item/placement-strategies.ts b/packages/editor/src/components/tools/item/placement-strategies.ts
index 4a6f4a7d..74bbc457 100644
--- a/packages/editor/src/components/tools/item/placement-strategies.ts
+++ b/packages/editor/src/components/tools/item/placement-strategies.ts
@@ -113,10 +113,14 @@ export const floorStrategy = {
     // is rotated; then project the world point back into building-local
     // for storage. Without this, a rotated building drags placement off
     // the world grid.
-    const snappedWorldX = snapToGrid(event.position[0], swapDims ? dimZ : dimX)
-    const snappedWorldZ = snapToGrid(event.position[2], swapDims ? dimX : dimZ)
-    const { local } = snapWorldXZForActiveBuilding(snappedWorldX, snappedWorldZ, 0)
-    const [x, z] = local
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const [x, z] = bypassSnap
+      ? [event.localPosition[0], event.localPosition[2]]
+      : snapWorldXZForActiveBuilding(
+          snapToGrid(event.position[0], swapDims ? dimZ : dimX),
+          snapToGrid(event.position[2], swapDims ? dimX : dimZ),
+          0,
+        ).local
     const y = ctx.gridPosition.y
 
     return {
@@ -197,9 +201,10 @@ export const wallStrategy = {
     const itemRotation = calculateItemRotation(event.normal)
     const cursorRotation = calculateCursorRotation(event.normal, event.node.start, event.node.end)
 
-    const x = snapToHalf(event.localPosition[0])
-    const y = snapToHalf(event.localPosition[1])
-    const z = snapToHalf(event.localPosition[2])
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const x = bypassSnap ? event.localPosition[0] : snapToHalf(event.localPosition[0])
+    const y = bypassSnap ? event.localPosition[1] : snapToHalf(event.localPosition[1])
+    const z = bypassSnap ? event.localPosition[2] : snapToHalf(event.localPosition[2])
 
     // Get auto-adjusted Y position from validator
     const rawDims = ctx.draftItem
@@ -231,11 +236,13 @@ export const wallStrategy = {
       },
       cursorRotationY: cursorRotation,
       gridPosition: [x, adjustedY, z],
-      cursorPosition: [
-        snapToHalf(event.position[0]),
-        snapToHalf(event.position[1]),
-        snapToHalf(event.position[2]),
-      ],
+      cursorPosition: bypassSnap
+        ? [event.position[0], event.position[1], event.position[2]]
+        : [
+            snapToHalf(event.position[0]),
+            snapToHalf(event.position[1]),
+            snapToHalf(event.position[2]),
+          ],
       stopPropagation: true,
     }
   },
@@ -258,9 +265,10 @@ export const wallStrategy = {
     const itemRotation = calculateItemRotation(event.normal)
     const cursorRotation = calculateCursorRotation(event.normal, event.node.start, event.node.end)
 
-    const snappedX = snapToHalf(event.localPosition[0])
-    const snappedY = snapToHalf(event.localPosition[1])
-    const snappedZ = snapToHalf(event.localPosition[2])
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const snappedX = bypassSnap ? event.localPosition[0] : snapToHalf(event.localPosition[0])
+    const snappedY = bypassSnap ? event.localPosition[1] : snapToHalf(event.localPosition[1])
+    const snappedZ = bypassSnap ? event.localPosition[2] : snapToHalf(event.localPosition[2])
 
     // Get auto-adjusted Y position from validator
     const validation = validators.canPlaceOnWall(
@@ -278,11 +286,13 @@ export const wallStrategy = {
 
     return {
       gridPosition: [snappedX, adjustedY, snappedZ],
-      cursorPosition: [
-        snapToHalf(event.position[0]),
-        snapToHalf(event.position[1]),
-        snapToHalf(event.position[2]),
-      ],
+      cursorPosition: bypassSnap
+        ? [event.position[0], event.position[1], event.position[2]]
+        : [
+            snapToHalf(event.position[0]),
+            snapToHalf(event.position[1]),
+            snapToHalf(event.position[2]),
+          ],
       cursorRotationY: cursorRotation,
       nodeUpdate: {
         position: [snappedX, adjustedY, snappedZ],
@@ -403,8 +413,8 @@ function resolveRoofWallTarget(
   const dims = getGridAlignedDimensions(rawDims, attachTo)
   const [width, height] = dims
 
-  const u = snapToHalf(hit.u)
-  const centerV = snapToHalf(hit.v) + height / 2
+  const u = shiftFree ? hit.u : snapToHalf(hit.u)
+  const centerV = (shiftFree ? hit.v : snapToHalf(hit.v)) + height / 2
   const fitted = shiftFree ? null : clampRectToRoofWallFace(hit.face, u, centerV, width, height)
   if (!fitted && !shiftFree) return null
   const finalU = fitted?.u ?? u
@@ -604,8 +614,13 @@ export const ceilingStrategy = {
 
     // Ceiling items are stored in ceiling-local coordinates, so snapping must
     // use the ceiling hit's local position rather than world position.
-    const x = snapToGrid(event.localPosition[0], swapDims ? dimZ : dimX)
-    const z = snapToGrid(event.localPosition[2], swapDims ? dimX : dimZ)
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const x = bypassSnap
+      ? event.localPosition[0]
+      : snapToGrid(event.localPosition[0], swapDims ? dimZ : dimX)
+    const z = bypassSnap
+      ? event.localPosition[2]
+      : snapToGrid(event.localPosition[2], swapDims ? dimX : dimZ)
     // Recessed fixtures seat flush with the ceiling plane (body rising into the
     // void above); everything else hangs its full height below the ceiling.
     const seatY = ctx.asset.recessed ? 0 : -itemHeight
@@ -638,8 +653,13 @@ export const ceilingStrategy = {
     const rotY = ctx.draftItem.rotation?.[1] ?? 0
     const swapDims = Math.abs(Math.sin(rotY)) > 0.9
 
-    const x = snapToGrid(event.localPosition[0], swapDims ? dimZ : dimX)
-    const z = snapToGrid(event.localPosition[2], swapDims ? dimX : dimZ)
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const x = bypassSnap
+      ? event.localPosition[0]
+      : snapToGrid(event.localPosition[0], swapDims ? dimZ : dimX)
+    const z = bypassSnap
+      ? event.localPosition[2]
+      : snapToGrid(event.localPosition[2], swapDims ? dimX : dimZ)
     // Recessed fixtures seat flush with the ceiling plane (body rising into the
     // void above); everything else hangs its full height below the ceiling.
     const seatY = ctx.draftItem.asset.recessed ? 0 : -itemHeight
@@ -750,8 +770,9 @@ export const itemSurfaceStrategy = {
     const surfaceHeight = getSurfacePlacementHeight(surfaceItem, event, localPos)
     if (surfaceHeight === null) return null
 
-    const x = snapToGrid(localPos.x, ourDims[0])
-    const z = snapToGrid(localPos.z, ourDims[2])
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const x = bypassSnap ? localPos.x : snapToGrid(localPos.x, ourDims[0])
+    const z = bypassSnap ? localPos.z : snapToGrid(localPos.z, ourDims[2])
     const y = surfaceHeight
 
     const worldSnapped = surfaceMesh.localToWorld(new Vector3(x, y, z))
@@ -801,8 +822,9 @@ export const itemSurfaceStrategy = {
     const surfaceHeight = getSurfacePlacementHeight(surfaceItem, event, localPos)
     if (surfaceHeight === null) return null
 
-    const x = snapToGrid(localPos.x, ourDims[0])
-    const z = snapToGrid(localPos.z, ourDims[2])
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const x = bypassSnap ? localPos.x : snapToGrid(localPos.x, ourDims[0])
+    const z = bypassSnap ? localPos.z : snapToGrid(localPos.z, ourDims[2])
     const y = surfaceHeight
 
     const worldSnapped = surfaceMesh.localToWorld(new Vector3(x, y, z))
@@ -901,8 +923,9 @@ export const shelfSurfaceStrategy = {
     const rowY = getShelfRowSurfaceY(shelfNode, localPos.y)
     if (rowY === null) return null
 
-    const x = snapToGrid(localPos.x, ourDims[0])
-    const z = snapToGrid(localPos.z, ourDims[2])
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const x = bypassSnap ? localPos.x : snapToGrid(localPos.x, ourDims[0])
+    const z = bypassSnap ? localPos.z : snapToGrid(localPos.z, ourDims[2])
 
     const worldSnapped = shelfMesh.localToWorld(new Vector3(x, rowY, z))
 
@@ -945,8 +968,9 @@ export const shelfSurfaceStrategy = {
     const rowY = getShelfRowSurfaceY(shelfNode, localPos.y)
     if (rowY === null) return null
 
-    const x = snapToGrid(localPos.x, ourDims[0])
-    const z = snapToGrid(localPos.z, ourDims[2])
+    const bypassSnap = event.nativeEvent?.shiftKey === true
+    const x = bypassSnap ? localPos.x : snapToGrid(localPos.x, ourDims[0])
+    const z = bypassSnap ? localPos.z : snapToGrid(localPos.z, ourDims[2])
     const worldSnapped = shelfMesh.localToWorld(new Vector3(x, rowY, z))
 
     return {
diff --git a/packages/editor/src/components/tools/item/use-placement-coordinator.tsx b/packages/editor/src/components/tools/item/use-placement-coordinator.tsx
index e47f2665..179f7b5e 100644
--- a/packages/editor/src/components/tools/item/use-placement-coordinator.tsx
+++ b/packages/editor/src/components/tools/item/use-placement-coordinator.tsx
@@ -683,11 +683,12 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
       // item's edge, snap and publish a guide. The guide connects to the
       // nearest real corner of the candidate (resolver tie-break), so the dot
       // always sits on an actual point. The delta is applied to BOTH the grid
-      // and cursor positions below. Alt bypasses.
+      // and cursor positions below. Alt bypasses alignment; Shift bypasses all snap.
       const draft = draftNode.current
       let alignX = 0
       let alignZ = 0
-      const bypassAlign = floorEvent.nativeEvent?.altKey === true
+      const bypassSnap = floorEvent.nativeEvent?.shiftKey === true
+      const bypassAlign = floorEvent.nativeEvent?.altKey === true || bypassSnap
       if (!bypassAlign && draft) {
         alignmentCandidates ??= collectAlignmentAnchors(
           useScene.getState().nodes,
@@ -721,6 +722,7 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
 
       // Play snap sound when grid position changes
       if (
+        !bypassSnap &&
         previousGridPos &&
         (gridPos[0] !== previousGridPos[0] || gridPos[2] !== previousGridPos[2])
       ) {
@@ -866,7 +868,7 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
         gridPosition.current.z !== result.gridPosition[2]
 
       // Play snap sound when grid position changes
-      if (posChanged) {
+      if (event.nativeEvent?.shiftKey !== true && posChanged) {
         sfxEmitter.emit('sfx:grid-snap')
       }
 
@@ -1035,7 +1037,7 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
         gridPosition.current.y !== result.gridPosition[1] ||
         gridPosition.current.z !== result.gridPosition[2]
 
-      if (posChanged) {
+      if (!shiftFreeRef.current && posChanged) {
         sfxEmitter.emit('sfx:grid-snap')
       }
 
@@ -1128,8 +1130,9 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
         event.position[1],
         event.position[2],
       )
-      const wx = Math.round(buildingLocalPoint.x * 2) / 2
-      const wz = Math.round(buildingLocalPoint.z * 2) / 2
+      const bypassSnap = event.nativeEvent?.shiftKey === true
+      const wx = bypassSnap ? buildingLocalPoint.x : Math.round(buildingLocalPoint.x * 2) / 2
+      const wz = bypassSnap ? buildingLocalPoint.z : Math.round(buildingLocalPoint.z * 2) / 2
       const floorPos: [number, number, number] = [wx, 0, wz]
 
       Object.assign(placementState.current, {
@@ -1429,7 +1432,7 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
         gridPosition.current.y !== result.gridPosition[1] ||
         gridPosition.current.z !== result.gridPosition[2]
 
-      if (posChanged) {
+      if (event.nativeEvent?.shiftKey !== true && posChanged) {
         sfxEmitter.emit('sfx:grid-snap')
       }
 
diff --git a/packages/editor/src/components/tools/registry/move-registry-node-tool.tsx b/packages/editor/src/components/tools/registry/move-registry-node-tool.tsx
index 5ac09d65..40078ee8 100644
--- a/packages/editor/src/components/tools/registry/move-registry-node-tool.tsx
+++ b/packages/editor/src/components/tools/registry/move-registry-node-tool.tsx
@@ -40,8 +40,8 @@ const snapToGridStep = (value: number) => {
   return Math.round(value / step) * step
 }
 
-/** 90° steps, matching the GLB item placement rotation. */
-const ROTATION_STEP = Math.PI / 2
+/** 45° steps, matching the GLB item placement rotation. */
+const ROTATION_STEP = Math.PI / 4
 
 /** Figma-style alignment-snap threshold (meters), matching the 2D
  *  floor-plan overlay's `ALIGNMENT_THRESHOLD_M`. 8 cm gives a magnetic pull
@@ -286,7 +286,7 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
         original: [originalPosition[0], originalPosition[2]],
         anchor: dragAnchorRef.current,
         mode: useAbsoluteCursorPlacement ? 'absolute' : 'relative',
-        snap: snapToGridStep,
+        snap: event.nativeEvent?.shiftKey === true ? (value) => value : snapToGridStep,
       })
       dragAnchorRef.current = resolved.anchor
       let [x, z] = resolved.point
@@ -295,8 +295,8 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
       // moving item's edge lines up (on X or Z) with another item's edge,
       // snap and publish a guide. The guide connects to the nearest real
       // corner of the candidate (resolver tie-break), so the dot always sits
-      // on an actual point. Alt bypasses.
-      const bypass = event.nativeEvent?.altKey === true
+      // on an actual point. Alt bypasses alignment; Shift bypasses all snap.
+      const bypass = event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true
       if (!bypass && alignmentCandidates.length > 0) {
         const result = resolveAlignment({
           moving: movingFootprintAnchors(node, x, z, rotationRef.current),
@@ -338,7 +338,7 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
       markMovedNodeDirty()
 
       const prev = previousSnapRef.current
-      if (!prev || prev[0] !== x || prev[1] !== z) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== x || prev[1] !== z)) {
         sfxEmitter.emit('sfx:grid-snap')
         previousSnapRef.current = [x, z]
       }
@@ -457,7 +457,7 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
       if (typeof direct === 'function') direct.call(event)
     }
 
-    // R / T rotate the dragged node about Y in 90° steps — matching the GLB
+    // R / T rotate the dragged node about Y in 45° steps — matching the GLB
     // item placement keys (and the "Rotate" hints the move HUD shows). Applied
     // imperatively + mirrored to the live transform; committed on drop.
     const onKeyDown = (e: KeyboardEvent) => {
diff --git a/packages/editor/src/components/tools/roof/roof-tool.tsx b/packages/editor/src/components/tools/roof/roof-tool.tsx
index 1bd9d8af..9b30cf23 100644
--- a/packages/editor/src/components/tools/roof/roof-tool.tsx
+++ b/packages/editor/src/components/tools/roof/roof-tool.tsx
@@ -242,17 +242,20 @@ export const RoofTool: React.FC = () => {
 
       // World-grid snap projected into building-local; rotated buildings
       // used to drag every roof corner off the visible grid.
-      const snapped = snapWorldXZForActiveBuilding(
-        event.position[0],
-        event.position[2],
-        useEditor.getState().gridSnapStep,
-      ).local
+      const bypassSnap = event.nativeEvent?.shiftKey === true
+      const snapped: [number, number] = bypassSnap
+        ? [event.localPosition[0], event.localPosition[2]]
+        : snapWorldXZForActiveBuilding(
+            event.position[0],
+            event.position[2],
+            useEditor.getState().gridSnapStep,
+          ).local
       const [gridX, gridZ] = alignPoint(
         snapped[0],
         snapped[1],
         event.localPosition[0],
         event.localPosition[2],
-        event.nativeEvent?.altKey === true,
+        event.nativeEvent?.altKey === true || bypassSnap,
       )
       const y = event.localPosition[1]
 
@@ -262,6 +265,7 @@ export const RoofTool: React.FC = () => {
       cursorRef.current.position.set(gridX, gridY, gridZ)
 
       if (
+        !bypassSnap &&
         corner1Ref.current &&
         previousGridPosRef.current &&
         (gridX !== previousGridPosRef.current[0] || gridZ !== previousGridPosRef.current[1])
@@ -287,17 +291,20 @@ export const RoofTool: React.FC = () => {
 
       // World-grid snap projected into building-local; rotated buildings
       // used to drag every roof corner off the visible grid.
-      const snapped = snapWorldXZForActiveBuilding(
-        event.position[0],
-        event.position[2],
-        useEditor.getState().gridSnapStep,
-      ).local
+      const bypassSnap = event.nativeEvent?.shiftKey === true
+      const snapped: [number, number] = bypassSnap
+        ? [event.localPosition[0], event.localPosition[2]]
+        : snapWorldXZForActiveBuilding(
+            event.position[0],
+            event.position[2],
+            useEditor.getState().gridSnapStep,
+          ).local
       const [gridX, gridZ] = alignPoint(
         snapped[0],
         snapped[1],
         event.localPosition[0],
         event.localPosition[2],
-        event.nativeEvent?.altKey === true,
+        event.nativeEvent?.altKey === true || bypassSnap,
       )
       const y = event.localPosition[1]
 
diff --git a/packages/editor/src/components/tools/shared/polygon-editor.tsx b/packages/editor/src/components/tools/shared/polygon-editor.tsx
index 5d9472ec..fcc1e7fb 100644
--- a/packages/editor/src/components/tools/shared/polygon-editor.tsx
+++ b/packages/editor/src/components/tools/shared/polygon-editor.tsx
@@ -746,7 +746,10 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
     const onGridMove = (event: GridEvent) => {
       const point = levelNode ? event.localPosition : event.position
       const rawPoint: [number, number] = [point[0], point[2]]
-      const gridPoint: [number, number] = [snapToHalf(rawPoint[0]), snapToHalf(rawPoint[1])]
+      const bypassSnap = event.nativeEvent.shiftKey === true
+      const gridPoint: [number, number] = bypassSnap
+        ? rawPoint
+        : [snapToHalf(rawPoint[0]), snapToHalf(rawPoint[1])]
       const newPosition =
         dragState?.isDragging && resolvePlanPoint
           ? resolvePlanPoint({
@@ -763,6 +766,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
 
       // Play snap sound when cursor moves to a new grid cell during drag
       if (
+        !bypassSnap &&
         dragState?.isDragging &&
         previousPositionRef.current &&
         (newPosition[0] !== previousPositionRef.current[0] ||
diff --git a/packages/editor/src/components/tools/stair/stair-tool.tsx b/packages/editor/src/components/tools/stair/stair-tool.tsx
index 6f2761bc..886abc40 100644
--- a/packages/editor/src/components/tools/stair/stair-tool.tsx
+++ b/packages/editor/src/components/tools/stair/stair-tool.tsx
@@ -348,18 +348,20 @@ export const StairTool: React.FC = () => {
     }
 
     const onGridMove = (event: GridEvent) => {
+      const bypassSnap = event.nativeEvent?.shiftKey === true
       const [gridX, gridZ] = alignPoint(
-        Math.round(event.localPosition[0] * 2) / 2,
-        Math.round(event.localPosition[2] * 2) / 2,
+        bypassSnap ? event.localPosition[0] : Math.round(event.localPosition[0] * 2) / 2,
+        bypassSnap ? event.localPosition[2] : Math.round(event.localPosition[2] * 2) / 2,
         event.localPosition[0],
         event.localPosition[2],
-        event.nativeEvent?.altKey === true,
+        event.nativeEvent?.altKey === true || bypassSnap,
       )
       const position: [number, number, number] = [gridX, 0, gridZ]
       lastCanonicalPositionRef.current = position
       applyDraftPreview(position, rotationRef.current)
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (gridX !== previousGridPosRef.current[0] || gridZ !== previousGridPosRef.current[1])
       ) {
@@ -370,12 +372,13 @@ export const StairTool: React.FC = () => {
     }
 
     const getAlignedGridPosition = (event: GridEvent): [number, number, number] => {
+      const bypassSnap = event.nativeEvent?.shiftKey === true
       const [gridX, gridZ] = alignPoint(
-        Math.round(event.localPosition[0] * 2) / 2,
-        Math.round(event.localPosition[2] * 2) / 2,
+        bypassSnap ? event.localPosition[0] : Math.round(event.localPosition[0] * 2) / 2,
+        bypassSnap ? event.localPosition[2] : Math.round(event.localPosition[2] * 2) / 2,
         event.localPosition[0],
         event.localPosition[2],
-        event.nativeEvent?.altKey === true,
+        event.nativeEvent?.altKey === true || bypassSnap,
       )
       return [gridX, 0, gridZ]
     }
diff --git a/packages/editor/src/components/tools/wall/wall-drafting.test.ts b/packages/editor/src/components/tools/wall/wall-drafting.test.ts
new file mode 100644
index 00000000..4ed03e2e
--- /dev/null
+++ b/packages/editor/src/components/tools/wall/wall-drafting.test.ts
@@ -0,0 +1,119 @@
+import { beforeEach, describe, expect, test } from 'bun:test'
+import {
+  type AnyNode,
+  type AnyNodeId,
+  useScene,
+  type WallNode,
+  WallNode as WallSchema,
+} from '@pascal-app/core'
+import { useViewer } from '@pascal-app/viewer'
+import { createWallOnCurrentLevel, snapWallDraftPointDetailed } from './wall-drafting'
+import type { WallPlanPoint } from './wall-snap-geometry'
+
+const LEVEL_ID = 'level_test' as AnyNodeId
+
+function makeWall(start: WallPlanPoint, end: WallPlanPoint, id: string): WallNode {
+  return {
+    ...WallSchema.parse({ start, end, name: id }),
+    id: id as WallNode['id'],
+    parentId: LEVEL_ID,
+  }
+}
+
+function seedLevel(walls: WallNode[]) {
+  useScene.setState({
+    nodes: Object.fromEntries([
+      [
+        LEVEL_ID,
+        {
+          id: LEVEL_ID,
+          type: 'level',
+          object: 'node',
+          parentId: null,
+          visible: true,
+          metadata: {},
+          children: walls.map((wall) => wall.id),
+          level: 0,
+        } as AnyNode,
+      ],
+      ...walls.map((wall) => [wall.id, wall] as const),
+    ]),
+    rootNodeIds: [LEVEL_ID],
+    dirtyNodes: new Set(),
+    collections: {},
+  } as never)
+}
+
+function levelWalls(): WallNode[] {
+  return Object.values(useScene.getState().nodes).filter(
+    (node): node is WallNode => node?.type === 'wall',
+  )
+}
+
+describe('createWallOnCurrentLevel', () => {
+  beforeEach(() => {
+    useViewer.setState({
+      selection: {
+        buildingId: 'building_test',
+        levelId: LEVEL_ID,
+        zoneId: null,
+        selectedIds: [],
+      },
+    } as never)
+    seedLevel([makeWall([0, 0], [4, 0], 'wall_a')])
+  })
+
+  test('endpoint near an existing corner attaches to the corner instead of splitting', () => {
+    const created = createWallOnCurrentLevel([2, 2], [3.99, 0])
+
+    expect(created?.end).toEqual([4, 0])
+    const hostWall = useScene.getState().nodes['wall_a' as AnyNodeId] as WallNode | undefined
+    expect(hostWall?.start).toEqual([0, 0])
+    expect(hostWall?.end).toEqual([4, 0])
+    expect(levelWalls()).toHaveLength(2)
+  })
+
+  test('endpoint near the host start corner snaps there without splitting', () => {
+    const created = createWallOnCurrentLevel([2, 2], [0.015, 0])
+
+    expect(created?.end).toEqual([0, 0])
+    expect(useScene.getState().nodes['wall_a' as AnyNodeId]).toBeDefined()
+    expect(levelWalls()).toHaveLength(2)
+  })
+
+  test('genuine mid-wall endpoint still splits the host (T junction)', () => {
+    const created = createWallOnCurrentLevel([2, 2], [2, 0])
+
+    expect(created?.end).toEqual([2, 0])
+    expect(useScene.getState().nodes['wall_a' as AnyNodeId]).toBeUndefined()
+    const walls = levelWalls()
+    expect(walls).toHaveLength(3)
+    expect(
+      walls.some((wall) => wall.start[0] === 0 && wall.end[0] === 2 && wall.end[1] === 0),
+    ).toBe(true)
+    expect(
+      walls.some((wall) => wall.start[0] === 2 && wall.start[1] === 0 && wall.end[0] === 4),
+    ).toBe(true)
+  })
+
+  test('exact duplicate segment is rejected', () => {
+    expect(createWallOnCurrentLevel([0, 0], [4, 0])).toBeNull()
+    expect(levelWalls()).toHaveLength(1)
+  })
+})
+
+describe('snapWallDraftPointDetailed', () => {
+  test('bypassSnap returns the raw point without endpoint or angle snap', () => {
+    const wall = makeWall([0, 0], [4, 0], 'wall_a')
+    const result = snapWallDraftPointDetailed({
+      point: [3.99, 0.03],
+      walls: [wall],
+      start: [2, 2],
+      angleSnap: true,
+      bypassSnap: true,
+    })
+
+    expect(result.point).toEqual([3.99, 0.03])
+    expect(result.snap).toBeNull()
+  })
+})
diff --git a/packages/editor/src/components/tools/wall/wall-drafting.ts b/packages/editor/src/components/tools/wall/wall-drafting.ts
index 4491c70f..3667e1af 100644
--- a/packages/editor/src/components/tools/wall/wall-drafting.ts
+++ b/packages/editor/src/components/tools/wall/wall-drafting.ts
@@ -1,9 +1,11 @@
 import {
   type AnyNode,
   type AnyNodeId,
+  DEFAULT_ANGLE_STEP,
   type DoorNode,
   getScaledDimensions,
   type ItemNode,
+  snapPointAlongAngleRay,
   useScene,
   type WallNode,
   WallNode as WallSchema,
@@ -35,21 +37,16 @@ export {
 } from './wall-snap-geometry'
 
 export const WALL_GRID_STEP = 0.5
-// Smallest available grid snap. Used as a precision-mode step (Shift +
-// drag) so a drag can land on values the regular grid skips.
-export const WALL_FINE_GRID_STEP = 0.05
 export const WALL_MIN_LENGTH = 0.01
-const DEFAULT_WALL_ANGLE_SNAP_STEP = Math.PI / 4
-
-const WALL_ANGLE_SNAP_BY_GRID_STEP: Record<number, number> = {
-  0.5: Math.PI / 4,
-  0.25: Math.PI / 8,
-  0.1: Math.PI / 12,
-  0.05: Math.PI / 36,
-}
+// An endpoint projecting within this distance of an existing wall's corner
+// resolves to the corner without splitting — splitting there would mint a
+// sliver segment a hair longer than `WALL_MIN_LENGTH` that no snap radius
+// can ever target again.
+const WALL_SPLIT_ENDPOINT_EPSILON = 0.02
 
 type WallSplitIntersection = {
-  wallId: WallNode['id']
+  /** `null` = snap-only outcome: resolve to `point` but split no wall. */
+  wallId: WallNode['id'] | null
   point: WallPlanPoint
 }
 
@@ -65,35 +62,6 @@ export function snapPointToGrid(point: WallPlanPoint, step = WALL_GRID_STEP): Wa
   return [snapScalarToGrid(point[0], step), snapScalarToGrid(point[1], step)]
 }
 
-export function snapPointTo45Degrees(
-  start: WallPlanPoint,
-  cursor: WallPlanPoint,
-  step = WALL_GRID_STEP,
-  angleStep = DEFAULT_WALL_ANGLE_SNAP_STEP,
-  /**
-   * Optional grid-snap callback. Lets the caller route the final
-   * snap through a world-XZ grid (or any other axis system) instead
-   * of the local-axis grid `snapPointToGrid` uses. When omitted,
-   * falls back to the local-axis snap at `step`.
-   */
-  gridSnap?: (point: WallPlanPoint) => WallPlanPoint,
-): WallPlanPoint {
-  const dx = cursor[0] - start[0]
-  const dz = cursor[1] - start[1]
-  const angle = Math.atan2(dz, dx)
-  const snappedAngle = Math.round(angle / angleStep) * angleStep
-  const distance = Math.sqrt(dx * dx + dz * dz)
-  const point: WallPlanPoint = [
-    start[0] + Math.cos(snappedAngle) * distance,
-    start[1] + Math.sin(snappedAngle) * distance,
-  ]
-  return gridSnap ? gridSnap(point) : snapPointToGrid(point, step)
-}
-
-export function getWallAngleSnapStep(step = getSegmentGridStep()): number {
-  return WALL_ANGLE_SNAP_BY_GRID_STEP[step] ?? DEFAULT_WALL_ANGLE_SNAP_STEP
-}
-
 function splitWallAtPoint(wall: WallNode, splitPoint: WallPlanPoint): [WallNode, WallNode] {
   const { id: _id, parentId: _parentId, children, ...rest } = wall
 
@@ -140,7 +108,14 @@ function findWallIntersection(
       continue
     }
 
-    best = { wallId: wall.id, point: projected }
+    const nearCorner = ([wall.start, wall.end] as WallPlanPoint[]).find(
+      (corner) =>
+        distanceSquared(projected, corner) <=
+        WALL_SPLIT_ENDPOINT_EPSILON * WALL_SPLIT_ENDPOINT_EPSILON,
+    )
+    best = nearCorner
+      ? { wallId: null, point: [nearCorner[0], nearCorner[1]] }
+      : { wallId: wall.id, point: projected }
     bestDistanceSquared = candidateDistanceSquared
   }
 
@@ -292,6 +267,10 @@ function splitWallIfNeeded(
 ): { walls: WallNode[]; point: WallPlanPoint } | null {
   if (!intersection) return null
 
+  if (!intersection.wallId) {
+    return { walls, point: intersection.point }
+  }
+
   const wallToSplit = walls.find((wall) => wall.id === intersection.wallId)
   if (!wallToSplit) {
     return { walls, point: intersection.point }
@@ -331,7 +310,8 @@ type SnapWallDraftArgs = {
   start?: WallPlanPoint
   angleSnap?: boolean
   ignoreWallIds?: string[]
-  /** Override the grid step (e.g. `WALL_FINE_GRID_STEP` for precision mode). */
+  bypassSnap?: boolean
+  /** Override the grid step. */
   step?: number
   /**
    * Magnetic snapping to existing wall geometry (corners, midpoints,
@@ -358,12 +338,15 @@ export function snapWallDraftPointDetailed(args: SnapWallDraftArgs): WallDraftSn
     start,
     angleSnap = false,
     ignoreWallIds,
+    bypassSnap = false,
     step: overrideStep,
     magnetic = true,
     gridSnap,
     snapRadii,
   } = args
 
+  if (bypassSnap) return { point, snap: null }
+
   // Discrete special points (corner / midpoint / crossing) are taken from the
   // raw cursor so an interim grid snap can't mask them. A corner always wins,
   // then the nearer of midpoint / crossing — see `findWallSpecialPointSnap`.
@@ -373,10 +356,12 @@ export function snapWallDraftPointDetailed(args: SnapWallDraftArgs): WallDraftSn
   }
 
   const step = overrideStep ?? getSegmentGridStep()
-  const angleStep = getWallAngleSnapStep(step)
-  const basePoint =
+  // The angle path snaps the distance ALONG the 15° ray — a scalar, the
+  // same in world and local frames — so the `gridSnap` world-grid override
+  // only applies when the angle lock is off.
+  const basePoint: WallPlanPoint =
     start && angleSnap
-      ? snapPointTo45Degrees(start, point, step, angleStep, gridSnap)
+      ? [...snapPointAlongAngleRay(start, point, DEFAULT_ANGLE_STEP, step)]
       : gridSnap
         ? gridSnap(point)
         : snapPointToGrid(point, step)
diff --git a/packages/editor/src/components/tools/zone/zone-tool.tsx b/packages/editor/src/components/tools/zone/zone-tool.tsx
index 7ce8f0ae..5b74fb4e 100644
--- a/packages/editor/src/components/tools/zone/zone-tool.tsx
+++ b/packages/editor/src/components/tools/zone/zone-tool.tsx
@@ -1,4 +1,12 @@
-import { emitter, type GridEvent, type LevelNode, useScene, ZoneNode } from '@pascal-app/core'
+import {
+  DEFAULT_ANGLE_STEP,
+  emitter,
+  type GridEvent,
+  type LevelNode,
+  snapPointAlongAngleRay,
+  useScene,
+  ZoneNode,
+} from '@pascal-app/core'
 import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useMemo, useRef, useState } from 'react'
 import { BufferGeometry, DoubleSide, type Group, type Line, Shape, Vector3 } from 'three'
@@ -10,42 +18,6 @@ import { CursorSphere } from '../shared/cursor-sphere'
 
 const Y_OFFSET = 0.02
 
-/**
- * Snaps a point to the nearest axis-aligned or 45-degree diagonal from the last point
- */
-const calculateSnapPoint = (
-  lastPoint: [number, number],
-  currentPoint: [number, number],
-): [number, number] => {
-  const [x1, y1] = lastPoint
-  const [x, y] = currentPoint
-
-  const dx = x - x1
-  const dy = y - y1
-  const absDx = Math.abs(dx)
-  const absDy = Math.abs(dy)
-
-  // Calculate distances to horizontal, vertical, and diagonal lines
-  const horizontalDist = absDy
-  const verticalDist = absDx
-  const diagonalDist = Math.abs(absDx - absDy)
-
-  // Find the minimum distance to determine which axis to snap to
-  const minDist = Math.min(horizontalDist, verticalDist, diagonalDist)
-
-  if (minDist === diagonalDist) {
-    // Snap to 45° diagonal
-    const diagonalLength = Math.min(absDx, absDy)
-    return [x1 + Math.sign(dx) * diagonalLength, y1 + Math.sign(dy) * diagonalLength]
-  }
-  if (minDist === horizontalDist) {
-    // Snap to horizontal
-    return [x, y1]
-  }
-  // Snap to vertical
-  return [x1, y]
-}
-
 /**
  * Creates a zone with the given polygon points
  */
@@ -93,6 +65,7 @@ export const ZoneTool: React.FC = () => {
   const pointsRef = useRef<Array<[number, number]>>([])
   const previousSnappedPointRef = useRef<[number, number] | null>(null)
   const levelYRef = useRef(0) // Track current level Y position
+  const shiftPressed = useRef(false)
   const currentLevelId = useViewer((state) => state.selection.levelId)
   const setTool = useEditor((state) => state.setTool)
 
@@ -107,11 +80,30 @@ export const ZoneTool: React.FC = () => {
     if (!currentLevelId) return
 
     let cursorPosition: [number, number] = [0, 0]
+    let rawCursorPosition: [number, number] = [0, 0]
 
     // Initialize line geometries
     mainLineRef.current.geometry = new BufferGeometry()
     closingLineRef.current.geometry = new BufferGeometry()
 
+    // 15° angle snap from the last vertex by default. Shift bypasses all snap.
+    // Distance snaps along the ray so the vertex lands on
+    // grid-multiple lengths without leaving the ray.
+    const snapDraftPoint = (
+      lastPoint: [number, number],
+      gridPoint: [number, number],
+      rawPoint: [number, number],
+    ): [number, number] => {
+      if (shiftPressed.current) return rawPoint
+      const [x, z] = snapPointAlongAngleRay(
+        lastPoint,
+        rawPoint,
+        DEFAULT_ANGLE_STEP,
+        useEditor.getState().gridSnapStep,
+      )
+      return [x, z]
+    }
+
     const updateLines = () => {
       const points = pointsRef.current
       const y = levelYRef.current + Y_OFFSET
@@ -128,7 +120,7 @@ export const ZoneTool: React.FC = () => {
       // Add cursor point
       const lastPoint = points[points.length - 1]
       if (lastPoint) {
-        const snapped = calculateSnapPoint(lastPoint, cursorPosition)
+        const snapped = snapDraftPoint(lastPoint, cursorPosition, rawCursorPosition)
         if (isValidPoint(snapped)) {
           linePoints.push(new Vector3(snapped[0], y, snapped[1]))
         }
@@ -146,7 +138,7 @@ export const ZoneTool: React.FC = () => {
       // Update closing line (from cursor back to first point)
       const firstPoint = points[0]
       if (points.length >= 2 && lastPoint && isValidPoint(firstPoint)) {
-        const snapped = calculateSnapPoint(lastPoint, cursorPosition)
+        const snapped = snapDraftPoint(lastPoint, cursorPosition, rawCursorPosition)
         if (isValidPoint(snapped)) {
           const closingPoints = [
             new Vector3(snapped[0], y, snapped[1]),
@@ -167,7 +159,7 @@ export const ZoneTool: React.FC = () => {
 
       let cursorPt: [number, number] | null = null
       if (lastPoint) {
-        cursorPt = calculateSnapPoint(lastPoint, cursorPosition)
+        cursorPt = snapDraftPoint(lastPoint, cursorPosition, rawCursorPosition)
       } else if (points.length === 0) {
         cursorPt = cursorPosition
       }
@@ -181,22 +173,27 @@ export const ZoneTool: React.FC = () => {
 
       // World-grid snap projected into building-local; rotated buildings
       // used to pull the snap off the visible grid lines.
-      const [gridX, gridZ] = snapWorldXZForActiveBuilding(
-        event.position[0],
-        event.position[2],
-        useEditor.getState().gridSnapStep,
-      ).local
+      const bypassSnap = shiftPressed.current || event.nativeEvent?.shiftKey === true
+      const [gridX, gridZ] = bypassSnap
+        ? [event.localPosition[0], event.localPosition[2]]
+        : snapWorldXZForActiveBuilding(
+            event.position[0],
+            event.position[2],
+            useEditor.getState().gridSnapStep,
+          ).local
       cursorPosition = [gridX, gridZ]
+      rawCursorPosition = [event.localPosition[0], event.localPosition[2]]
       levelYRef.current = event.localPosition[1]
 
-      // If we have points, snap to axis from last point
+      // If we have points, snap to the 15° ray from the last point
       const lastPoint = pointsRef.current[pointsRef.current.length - 1]
       const displayPoint = lastPoint
-        ? calculateSnapPoint(lastPoint, cursorPosition)
+        ? snapDraftPoint(lastPoint, cursorPosition, rawCursorPosition)
         : cursorPosition
 
       // Play snap sound when the snapped position changes during drawing
       if (
+        !bypassSnap &&
         pointsRef.current.length > 0 &&
         previousSnappedPointRef.current &&
         (displayPoint[0] !== previousSnappedPointRef.current[0] ||
@@ -214,17 +211,23 @@ export const ZoneTool: React.FC = () => {
     const onGridClick = (event: GridEvent) => {
       if (!currentLevelId) return
 
-      const [gridX, gridZ] = snapWorldXZForActiveBuilding(
-        event.position[0],
-        event.position[2],
-        useEditor.getState().gridSnapStep,
-      ).local
+      const bypassSnap = shiftPressed.current || event.nativeEvent?.shiftKey === true
+      const [gridX, gridZ] = bypassSnap
+        ? [event.localPosition[0], event.localPosition[2]]
+        : snapWorldXZForActiveBuilding(
+            event.position[0],
+            event.position[2],
+            useEditor.getState().gridSnapStep,
+          ).local
       let clickPoint: [number, number] = [gridX, gridZ]
 
-      // Snap to axis from last point
+      // Snap to the 15° ray from the last point
       const lastPoint = pointsRef.current[pointsRef.current.length - 1]
       if (lastPoint) {
-        clickPoint = calculateSnapPoint(lastPoint, clickPoint)
+        clickPoint = snapDraftPoint(lastPoint, clickPoint, [
+          event.localPosition[0],
+          event.localPosition[2],
+        ])
       }
 
       // Check if clicking on the first point to close the shape
@@ -267,12 +270,28 @@ export const ZoneTool: React.FC = () => {
       }
     }
 
+    const onKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'Shift') shiftPressed.current = true
+    }
+    const onKeyUp = (e: KeyboardEvent) => {
+      if (e.key === 'Shift') shiftPressed.current = false
+    }
+    const onWindowBlur = () => {
+      shiftPressed.current = false
+    }
+    document.addEventListener('keydown', onKeyDown)
+    document.addEventListener('keyup', onKeyUp)
+    window.addEventListener('blur', onWindowBlur)
+
     // Subscribe to events
     emitter.on('grid:move', onGridMove)
     emitter.on('grid:click', onGridClick)
     emitter.on('grid:double-click', onGridDoubleClick)
 
     return () => {
+      document.removeEventListener('keydown', onKeyDown)
+      document.removeEventListener('keyup', onKeyUp)
+      window.removeEventListener('blur', onWindowBlur)
       emitter.off('grid:move', onGridMove)
       emitter.off('grid:click', onGridClick)
       emitter.off('grid:double-click', onGridDoubleClick)
diff --git a/packages/editor/src/components/ui/sidebar/panels/settings-panel/keyboard-shortcuts-dialog.tsx b/packages/editor/src/components/ui/sidebar/panels/settings-panel/keyboard-shortcuts-dialog.tsx
index a2a03356..c27d0dde 100644
--- a/packages/editor/src/components/ui/sidebar/panels/settings-panel/keyboard-shortcuts-dialog.tsx
+++ b/packages/editor/src/components/ui/sidebar/panels/settings-panel/keyboard-shortcuts-dialog.tsx
@@ -80,8 +80,13 @@ const SHORTCUT_CATEGORIES: ShortcutCategory[] = [
     shortcuts: [
       {
         keys: ['Shift'],
-        action: 'Temporarily disable angle snapping while drawing walls, slabs, and ceilings',
-        note: 'Hold while drawing.',
+        action: 'Draw at any angle, bypassing the default 15° angle snap',
+        note: 'Hold while drawing walls, fences, slabs, ceilings, and zones.',
+      },
+      {
+        keys: ['Shift'],
+        action: 'Rotate freely, bypassing the default 15° rotation snap',
+        note: 'Hold while dragging a rotate handle.',
       },
     ],
   },
diff --git a/packages/editor/src/hooks/use-drag-action.ts b/packages/editor/src/hooks/use-drag-action.ts
index 97674f79..b0c95237 100644
--- a/packages/editor/src/hooks/use-drag-action.ts
+++ b/packages/editor/src/hooks/use-drag-action.ts
@@ -19,7 +19,10 @@ import { useEffect, useRef } from 'react'
 const sceneApi = createSceneApi(useScene)
 
 function modifiersFromGridEvent(event: GridEvent): Modifiers {
-  const ne = event.nativeEvent?.nativeEvent as Partial<KeyboardEvent> | undefined
+  // Both grid-event emit paths (use-grid-events.ts and the floorplan panel)
+  // store the raw DOM event directly at `.nativeEvent` — there is no second
+  // `.nativeEvent` hop.
+  const ne = event.nativeEvent as Partial<MouseEvent> | undefined
   return {
     shift: ne?.shiftKey ?? false,
     alt: ne?.altKey ?? false,
diff --git a/packages/editor/src/index.tsx b/packages/editor/src/index.tsx
index 93b69ca7..6e0b0dde 100644
--- a/packages/editor/src/index.tsx
+++ b/packages/editor/src/index.tsx
@@ -104,7 +104,6 @@ export {
   snapScalarToGrid,
   snapWallDraftPoint,
   snapWallDraftPointDetailed,
-  WALL_FINE_GRID_STEP,
   WALL_GRID_STEP,
   type WallDraftSnapKind,
   type WallDraftSnapResult,
@@ -299,6 +298,7 @@ export {
   usePaletteViewRegistry,
 } from './store/use-palette-view-registry'
 export { default as usePlacementPreview } from './store/use-placement-preview'
+export { default as useSegmentDraftChain } from './store/use-segment-draft-chain'
 export { useUploadStore } from './store/use-upload'
 export { useWallMoveGhosts, type WallMoveGhostBridge } from './store/use-wall-move-ghosts'
 export {
diff --git a/packages/editor/src/lib/surface-plan-snap.ts b/packages/editor/src/lib/surface-plan-snap.ts
index 95693425..4d48a6b1 100644
--- a/packages/editor/src/lib/surface-plan-snap.ts
+++ b/packages/editor/src/lib/surface-plan-snap.ts
@@ -43,6 +43,7 @@ export type SurfacePlanSnapInput = {
   candidates?: readonly AlignmentAnchor[]
   threshold?: number
   altKey?: boolean
+  shiftKey?: boolean
   magnetic?: boolean
   align?: boolean
   highlightWalls?: boolean
@@ -171,6 +172,12 @@ export function clearSurfacePlanSnapFeedback() {
 }
 
 export function resolveSurfacePlanPointSnap(input: SurfacePlanSnapInput): SurfacePlanSnapResult {
+  if (input.shiftKey) {
+    useWallSnapIndicator.getState().clear()
+    useAlignmentGuides.getState().clear()
+    return { point: input.rawPoint, wallSnap: null, guides: [], wallIds: [] }
+  }
+
   const nodes = input.nodes ?? useScene.getState().nodes
   const walls = getLevelWalls(nodes, input.levelId, input.walls)
   const fallbackPoint = input.fallbackPoint
diff --git a/packages/editor/src/store/use-segment-draft-chain.ts b/packages/editor/src/store/use-segment-draft-chain.ts
new file mode 100644
index 00000000..b578f0ca
--- /dev/null
+++ b/packages/editor/src/store/use-segment-draft-chain.ts
@@ -0,0 +1,28 @@
+// Ephemeral store for the wall / fence tools' click-chaining start points.
+// The 3D tools (`@pascal-app/nodes` wall/tool.tsx, fence/tool.tsx) own node
+// creation for both views; after each chained commit they publish the
+// created segment's resolved end here so the 2D floor-plan draft chains its
+// next segment from the same point instead of re-deriving it through a
+// different snap pipeline. Cleared on cancel, single-segment commit, and
+// unmount — never persisted, never in undo history.
+
+import { create } from 'zustand'
+import type { WallPlanPoint } from '../components/tools/wall/wall-snap-geometry'
+
+type SegmentKind = 'wall' | 'fence'
+
+type SegmentDraftChainState = {
+  wall: WallPlanPoint | null
+  fence: WallPlanPoint | null
+  setChainStart(kind: SegmentKind, point: WallPlanPoint | null): void
+  clear(kind: SegmentKind): void
+}
+
+const useSegmentDraftChain = create<SegmentDraftChainState>((set) => ({
+  wall: null,
+  fence: null,
+  setChainStart: (kind, point) => set({ [kind]: point }),
+  clear: (kind) => set({ [kind]: null }),
+}))
+
+export default useSegmentDraftChain
diff --git a/packages/nodes/src/box-vent/move-tool.tsx b/packages/nodes/src/box-vent/move-tool.tsx
index 6f1cfd07..4a8b1da5 100644
--- a/packages/nodes/src/box-vent/move-tool.tsx
+++ b/packages/nodes/src/box-vent/move-tool.tsx
@@ -68,7 +68,10 @@ export default function MoveBoxVentTool({ node }: { node: BoxVentNode }) {
 
       const sx = Math.round(target.localX * 20) / 20
       const sz = Math.round(target.localZ * 20) / 20
-      if (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz) {
+      if (
+        event.nativeEvent?.shiftKey !== true &&
+        (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz)
+      ) {
         triggerSFX('sfx:grid-snap')
         lastSnap = [sx, sz]
       }
diff --git a/packages/nodes/src/box-vent/tool.tsx b/packages/nodes/src/box-vent/tool.tsx
index 814434db..4290d436 100644
--- a/packages/nodes/src/box-vent/tool.tsx
+++ b/packages/nodes/src/box-vent/tool.tsx
@@ -14,7 +14,7 @@ import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useMemo, useRef, useState } from 'react'
 import * as THREE from 'three'
 import { resolveRoofSegmentHit } from '../shared/roof-segment-hit'
-import { getAnalyticalNormal, surfaceQuatFromNormal } from '../shared/roof-surface'
+import { getAnalyticalNormal, getDownSlopeYaw, surfaceQuatFromNormal } from '../shared/roof-surface'
 import { boxVentDefinition } from './definition'
 import BoxVentPreview from './preview'
 
@@ -37,6 +37,7 @@ const BoxVentTool = () => {
   const [previewPos, setPreviewPos] = useState<[number, number, number] | null>(null)
   const [previewSurfaceQuat, setPreviewSurfaceQuat] = useState<THREE.Quaternion | null>(null)
   const [previewYaw, setPreviewYaw] = useState(0)
+  const [previewRotation, setPreviewRotation] = useState(0)
   const lastSnapRef = useRef<[number, number] | null>(null)
 
   // Default-shaped preview node — matches what the commit will create.
@@ -46,9 +47,9 @@ const BoxVentTool = () => {
         ...boxVentDefinition.defaults(),
         name: 'Box Vent',
         position: [0, 0, 0],
-        rotation: 0,
+        rotation: previewRotation,
       }),
-    [],
+    [previewRotation],
   )
 
   useEffect(() => {
@@ -70,7 +71,7 @@ const BoxVentTool = () => {
       const sx = Math.round(wx * 20) / 20
       const sz = Math.round(wz * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
@@ -81,6 +82,7 @@ const BoxVentTool = () => {
       const normal = getAnalyticalNormal(hit.localX, hit.localZ, hit.segment)
       setPreviewSurfaceQuat(surfaceQuatFromNormal(normal, new THREE.Quaternion()))
       setPreviewYaw((event.node.rotation ?? 0) + (hit.segment.rotation ?? 0))
+      setPreviewRotation(getDownSlopeYaw(hit.localX, hit.localZ, hit.segment))
       setPreviewPos(worldToBuildingLocal(wx, wy, wz))
       event.stopPropagation()
     }
@@ -100,7 +102,7 @@ const BoxVentTool = () => {
         name: 'Box Vent',
         roofSegmentId: hit.segment.id,
         position: [hit.localX, hit.localY, hit.localZ],
-        rotation: 0,
+        rotation: getDownSlopeYaw(hit.localX, hit.localZ, hit.segment),
       })
       state.createNode(vent, hit.segment.id as AnyNodeId)
       state.dirtyNodes.add(hit.segment.id as AnyNodeId)
diff --git a/packages/nodes/src/building/move-tool.tsx b/packages/nodes/src/building/move-tool.tsx
index c1196e77..91333f46 100644
--- a/packages/nodes/src/building/move-tool.tsx
+++ b/packages/nodes/src/building/move-tool.tsx
@@ -93,7 +93,7 @@ export function MoveBuildingContent({ node }: { node: BuildingNode }) {
         return
       }
 
-      const ROTATION_STEP = Math.PI / 2
+      const ROTATION_STEP = Math.PI / 4
       let rotationDelta = 0
       if (event.key === 'r' || event.key === 'R') rotationDelta = ROTATION_STEP
       else if (event.key === 't' || event.key === 'T') rotationDelta = -ROTATION_STEP
@@ -121,14 +121,16 @@ export function MoveBuildingContent({ node }: { node: BuildingNode }) {
     }
 
     const onGridMove = (event: GridEvent) => {
-      const rawX = Math.round(event.position[0] * 2) / 2
-      const rawZ = Math.round(event.position[2] * 2) / 2
+      const bypassSnap = event.nativeEvent?.shiftKey === true
+      const rawX = bypassSnap ? event.position[0] : Math.round(event.position[0] * 2) / 2
+      const rawZ = bypassSnap ? event.position[2] : Math.round(event.position[2] * 2) / 2
       const anchor = dragAnchorRef.current ?? [rawX, rawZ]
       dragAnchorRef.current = anchor
       const gridX = originalCenter[0] + (rawX - anchor[0])
       const gridZ = originalCenter[1] + (rawZ - anchor[1])
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (gridX !== previousGridPosRef.current[0] || gridZ !== previousGridPosRef.current[1])
       ) {
diff --git a/packages/nodes/src/ceiling/boundary-editor.tsx b/packages/nodes/src/ceiling/boundary-editor.tsx
index 9093b7fe..63f27ce0 100644
--- a/packages/nodes/src/ceiling/boundary-editor.tsx
+++ b/packages/nodes/src/ceiling/boundary-editor.tsx
@@ -126,6 +126,7 @@ export const CeilingBoundaryEditor: React.FC<{ ceilingId: CeilingNode['id'] }> =
         levelId: ceilingLevelId,
         excludeId: ceilingId,
         altKey: context.nativeEvent?.altKey === true,
+        shiftKey: context.nativeEvent?.shiftKey === true,
       }).point,
     [ceilingId, ceilingLevelId],
   )
diff --git a/packages/nodes/src/ceiling/floorplan-affordances.ts b/packages/nodes/src/ceiling/floorplan-affordances.ts
index 176906cc..d1802097 100644
--- a/packages/nodes/src/ceiling/floorplan-affordances.ts
+++ b/packages/nodes/src/ceiling/floorplan-affordances.ts
@@ -29,6 +29,7 @@ const ceilingSnapOptions = {
       excludeId: node.id,
       nodes: sceneNodes,
       altKey: modifiers.altKey,
+      shiftKey: modifiers.shiftKey,
     }).point
   },
 }
diff --git a/packages/nodes/src/ceiling/move-tool.tsx b/packages/nodes/src/ceiling/move-tool.tsx
index 3e255313..3914db44 100644
--- a/packages/nodes/src/ceiling/move-tool.tsx
+++ b/packages/nodes/src/ceiling/move-tool.tsx
@@ -147,10 +147,12 @@ export const MoveCeilingTool: React.FC<{ node: CeilingNode }> = ({ node }) => {
 
     const onGridMove = (event: GridEvent) => {
       if (isFloorplanSourcedEvent(event)) return
-      const localX = snap(event.localPosition[0])
-      const localZ = snap(event.localPosition[2])
+      const bypassSnap = event.nativeEvent?.shiftKey === true
+      const localX = bypassSnap ? event.localPosition[0] : snap(event.localPosition[0])
+      const localZ = bypassSnap ? event.localPosition[2] : snap(event.localPosition[2])
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (localX !== previousGridPosRef.current[0] || localZ !== previousGridPosRef.current[1])
       ) {
@@ -166,8 +168,8 @@ export const MoveCeilingTool: React.FC<{ node: CeilingNode }> = ({ node }) => {
 
       // Figma-style alignment snap: align the ceiling's translated polygon
       // vertices to other objects' anchors; fold the snap into the delta and
-      // publish a guide. Alt bypasses.
-      const bypass = event.nativeEvent?.altKey === true
+      // publish a guide. Alt bypasses alignment; Shift bypasses all snap.
+      const bypass = event.nativeEvent?.altKey === true || bypassSnap
       if (!bypass && alignmentCandidates.length > 0) {
         const result = resolveAlignment({
           moving: polygonAnchors(ceilingId, translatePolygon(originalPolygon, deltaX, deltaZ)),
diff --git a/packages/nodes/src/ceiling/tool.tsx b/packages/nodes/src/ceiling/tool.tsx
index d70c560f..f20bb607 100644
--- a/packages/nodes/src/ceiling/tool.tsx
+++ b/packages/nodes/src/ceiling/tool.tsx
@@ -1,6 +1,13 @@
 'use client'
 
-import { emitter, type GridEvent, type LevelNode, useScene } from '@pascal-app/core'
+import {
+  DEFAULT_ANGLE_STEP,
+  emitter,
+  type GridEvent,
+  type LevelNode,
+  snapPointAlongAngleRay,
+  useScene,
+} from '@pascal-app/core'
 import {
   CursorSphere,
   clearCeilingSnapFeedback,
@@ -22,34 +29,12 @@ import { CeilingNode } from './schema'
  * Multi-click polygon drawing at the ceiling height (2.52m default)
  * with a vertical TSL-gradient connector + ground-shadow lines so the
  * draft is visible against both the ceiling plane and the floor.
- * Shift defeats the axis/45° snap during drag.
+ * Shift defeats the 15° angle snap during drag.
  */
 
 const CEILING_HEIGHT = 2.52
 const GRID_OFFSET = 0.02
 
-function calculateSnapPoint(
-  lastPoint: [number, number],
-  currentPoint: [number, number],
-): [number, number] {
-  const [x1, y1] = lastPoint
-  const [x, y] = currentPoint
-  const dx = x - x1
-  const dy = y - y1
-  const absDx = Math.abs(dx)
-  const absDy = Math.abs(dy)
-  const horizontalDist = absDy
-  const verticalDist = absDx
-  const diagonalDist = Math.abs(absDx - absDy)
-  const minDist = Math.min(horizontalDist, verticalDist, diagonalDist)
-  if (minDist === diagonalDist) {
-    const diagonalLength = Math.min(absDx, absDy)
-    return [x1 + Math.sign(dx) * diagonalLength, y1 + Math.sign(dy) * diagonalLength]
-  }
-  if (minDist === horizontalDist) return [x, y1]
-  return [x1, y]
-}
-
 function commitCeilingDrawing(levelId: LevelNode['id'], points: Array<[number, number]>): string {
   const { createNode, nodes } = useScene.getState()
   const ceilingCount = Object.values(nodes).filter((n) => n.type === 'ceiling').length
@@ -107,26 +92,38 @@ export const CeilingTool: React.FC = () => {
     const onGridMove = (event: GridEvent) => {
       if (!(cursorRef.current && gridCursorRef.current)) return
       const rawPoint: [number, number] = [event.localPosition[0], event.localPosition[2]]
+      const bypassSnap = shiftPressed.current || event.nativeEvent?.shiftKey === true
       const gridX = Math.round(rawPoint[0] * 2) / 2
       const gridZ = Math.round(rawPoint[1] * 2) / 2
-      const gridPosition: [number, number] = [gridX, gridZ]
+      const gridPosition: [number, number] = bypassSnap ? rawPoint : [gridX, gridZ]
       setCursorPosition(gridPosition)
       setLevelY(event.localPosition[1])
       const ceilingY = event.localPosition[1] + CEILING_HEIGHT
       const gridY = event.localPosition[1] + GRID_OFFSET
       const lastPoint = points[points.length - 1]
-      const orthoPoint =
-        shiftPressed.current || !lastPoint
+      // 15° angle snap from the raw cursor (matching the 2D floorplan
+      // pipeline) with the distance snapped along the ray to the grid step.
+      const orthoPoint: [number, number] =
+        bypassSnap || !lastPoint
           ? gridPosition
-          : calculateSnapPoint(lastPoint, gridPosition)
+          : [
+              ...snapPointAlongAngleRay(
+                lastPoint,
+                rawPoint,
+                DEFAULT_ANGLE_STEP,
+                useEditor.getState().gridSnapStep,
+              ),
+            ]
       const displayPoint = resolveCeilingPlanPointSnap({
         rawPoint,
         fallbackPoint: orthoPoint,
         levelId: currentLevelId,
         altKey: event.nativeEvent?.altKey === true,
+        shiftKey: bypassSnap,
       }).point
       setSnappedCursorPosition(displayPoint)
       if (
+        !bypassSnap &&
         points.length > 0 &&
         previousSnappedPointRef.current &&
         (displayPoint[0] !== previousSnappedPointRef.current[0] ||
@@ -186,8 +183,12 @@ export const CeilingTool: React.FC = () => {
     const onKeyUp = (e: KeyboardEvent) => {
       if (e.key === 'Shift') shiftPressed.current = false
     }
+    const onWindowBlur = () => {
+      shiftPressed.current = false
+    }
     document.addEventListener('keydown', onKeyDown)
     document.addEventListener('keyup', onKeyUp)
+    window.addEventListener('blur', onWindowBlur)
 
     emitter.on('grid:move', onGridMove)
     emitter.on('grid:click', onGridClick)
@@ -197,6 +198,7 @@ export const CeilingTool: React.FC = () => {
     return () => {
       document.removeEventListener('keydown', onKeyDown)
       document.removeEventListener('keyup', onKeyUp)
+      window.removeEventListener('blur', onWindowBlur)
       emitter.off('grid:move', onGridMove)
       emitter.off('grid:click', onGridClick)
       emitter.off('grid:double-click', onGridDoubleClick)
diff --git a/packages/nodes/src/chimney/move-tool.tsx b/packages/nodes/src/chimney/move-tool.tsx
index c72908a5..c635bc03 100644
--- a/packages/nodes/src/chimney/move-tool.tsx
+++ b/packages/nodes/src/chimney/move-tool.tsx
@@ -97,7 +97,7 @@ const MoveChimneyTool = ({ node }: { node: ChimneyNode }) => {
       const sx = Math.round(target.localX * 20) / 20
       const sz = Math.round(target.localZ * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
diff --git a/packages/nodes/src/chimney/tool.tsx b/packages/nodes/src/chimney/tool.tsx
index 522caf28..5b319ca2 100644
--- a/packages/nodes/src/chimney/tool.tsx
+++ b/packages/nodes/src/chimney/tool.tsx
@@ -88,7 +88,7 @@ const ChimneyTool = () => {
       const sx = Math.round(wx * 20) / 20
       const sz = Math.round(wz * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
diff --git a/packages/nodes/src/column/floorplan-move.ts b/packages/nodes/src/column/floorplan-move.ts
index 73572f84..4ae6e1d0 100644
--- a/packages/nodes/src/column/floorplan-move.ts
+++ b/packages/nodes/src/column/floorplan-move.ts
@@ -63,7 +63,7 @@ export const columnFloorplanMoveTarget: FloorplanMoveTarget<ColumnNode> = ({ nod
         return Math.round(value / step) * step
       }
       const gridSnapped = resolveCursor(planPoint, { snap }) as WallPlanPoint
-      // Figma-style alignment layered on the grid snap (Alt bypasses).
+      // Figma-style alignment layered on the grid snap (Alt bypasses alignment; Shift all snap).
       const { point: snapped } = applyFloorplanAlignment(
         gridSnapped,
         movingFootprintAnchors(
@@ -73,13 +73,13 @@ export const columnFloorplanMoveTarget: FloorplanMoveTarget<ColumnNode> = ({ nod
           rotationY,
         ),
         candidates,
-        { bypass: modifiers.altKey },
+        { bypass: modifiers.altKey || modifiers.shiftKey },
       )
       const next: [number, number, number] = [snapped[0], originalPosition[1], snapped[1]]
       lastPosition = next
 
       const snapKey = `${snapped[0]},${snapped[1]}`
-      if (snapKey !== lastSnapKey) {
+      if (!modifiers.shiftKey && snapKey !== lastSnapKey) {
         triggerSFX('sfx:grid-snap')
         lastSnapKey = snapKey
       }
diff --git a/packages/nodes/src/column/move-tool.tsx b/packages/nodes/src/column/move-tool.tsx
index f9a31454..f2d645f4 100644
--- a/packages/nodes/src/column/move-tool.tsx
+++ b/packages/nodes/src/column/move-tool.tsx
@@ -50,8 +50,8 @@ const snapToGridStep = (value: number) => {
   return Math.round(value / step) * step
 }
 
-/** 90° steps, matching the GLB item / shelf placement rotation. */
-const ROTATION_STEP = Math.PI / 2
+/** 45° steps, matching the generic move tool's R/T rotation. */
+const ROTATION_STEP = Math.PI / 4
 
 /** Figma-style alignment-snap threshold (meters), matching the other tools. */
 const ALIGNMENT_THRESHOLD_M = 0.08
@@ -124,15 +124,15 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
         original: [node.position[0], node.position[2]],
         anchor: dragAnchor,
         mode: useAbsoluteCursorPlacement ? 'absolute' : 'relative',
-        snap: snapToGridStep,
+        snap: event.nativeEvent?.shiftKey === true ? (value) => value : snapToGridStep,
       })
       dragAnchor = resolved.anchor
       let [x, z] = resolved.point
 
-      // Figma-style alignment snap on top of grid snap; Alt bypasses. The
+      // Figma-style alignment snap on top of grid snap; Alt bypasses alignment; Shift all snap. The
       // guide connects to the candidate's nearest real anchor (resolver
       // tie-break), so the dot always sits on an actual point.
-      const bypass = event.nativeEvent?.altKey === true
+      const bypass = event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true
       if (!bypass && alignmentCandidates.length > 0) {
         const result = resolveAlignment({
           moving: movingFootprintAnchors(node, x, z, rotationY),
@@ -151,7 +151,7 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
       applyPreview([x, 0, z])
     }
 
-    // R / T rotate the dragged column about Y in 90° steps (matches the move
+    // R / T rotate the dragged column about Y in 45° steps (matches the move
     // HUD's "Rotate" hints), committed on drop.
     const onKeyDown = (e: KeyboardEvent) => {
       if (e.metaKey || e.ctrlKey || e.altKey) return
diff --git a/packages/nodes/src/column/tool.tsx b/packages/nodes/src/column/tool.tsx
index 6b221b4a..c8e1bc7b 100644
--- a/packages/nodes/src/column/tool.tsx
+++ b/packages/nodes/src/column/tool.tsx
@@ -87,7 +87,8 @@ const ColumnTool = () => {
         rawZ: event.localPosition[2],
         gridStep: useEditor.getState().gridSnapStep,
         candidates: alignmentCandidates,
-        bypassAlignment: event.nativeEvent?.altKey === true,
+        bypassAlignment: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassGrid: event.nativeEvent?.shiftKey === true,
       })
       useAlignmentGuides.getState().set(guides)
 
@@ -107,7 +108,10 @@ const ColumnTool = () => {
       usePlacementPreview.getState().set({ ...previewNode, position })
 
       const prev = previousSnapRef.current
-      if (!prev || prev[0] !== position[0] || prev[1] !== position[2]) {
+      if (
+        event.nativeEvent?.shiftKey !== true &&
+        (!prev || prev[0] !== position[0] || prev[1] !== position[2])
+      ) {
         triggerSFX('sfx:grid-snap')
         previousSnapRef.current = [position[0], position[2]]
       }
@@ -116,7 +120,12 @@ const ColumnTool = () => {
     const commitAtCursor = (event: FloorPlacementClickTriggerEvent) => {
       const position =
         lastCursorRef.current ??
-        getLevelLocalSnappedPosition(activeLevelId, event, useEditor.getState().gridSnapStep)
+        getLevelLocalSnappedPosition(
+          activeLevelId,
+          event,
+          useEditor.getState().gridSnapStep,
+          event.nativeEvent?.shiftKey === true,
+        )
 
       const column = createColumnFromPreset(DEFAULT_COLUMN_PRESET_ID, position)
       useScene.getState().createNode(column, activeLevelId)
diff --git a/packages/nodes/src/cupola/move-tool.tsx b/packages/nodes/src/cupola/move-tool.tsx
index 2d6f9b27..40e50b30 100644
--- a/packages/nodes/src/cupola/move-tool.tsx
+++ b/packages/nodes/src/cupola/move-tool.tsx
@@ -66,7 +66,10 @@ export default function MoveCupolaTool({ node }: { node: CupolaNode }) {
 
       const sx = Math.round(target.localX * 20) / 20
       const sz = Math.round(target.localZ * 20) / 20
-      if (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz) {
+      if (
+        event.nativeEvent?.shiftKey !== true &&
+        (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz)
+      ) {
         triggerSFX('sfx:grid-snap')
         lastSnap = [sx, sz]
       }
diff --git a/packages/nodes/src/cupola/tool.tsx b/packages/nodes/src/cupola/tool.tsx
index 857a3f75..9b6e1996 100644
--- a/packages/nodes/src/cupola/tool.tsx
+++ b/packages/nodes/src/cupola/tool.tsx
@@ -64,7 +64,7 @@ const CupolaTool = () => {
       const sx = Math.round(wx * 20) / 20
       const sz = Math.round(wz * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
diff --git a/packages/nodes/src/door/floorplan-move.ts b/packages/nodes/src/door/floorplan-move.ts
index d6433a7f..d488a791 100644
--- a/packages/nodes/src/door/floorplan-move.ts
+++ b/packages/nodes/src/door/floorplan-move.ts
@@ -83,16 +83,17 @@ export const doorFloorplanMoveTarget: FloorplanMoveTarget<DoorNode> = ({ node })
       // Figma-style along-wall alignment first (edge-to-edge with other
       // openings / wall ends); it competes with — and wins over — the 0.5m
       // grid snap. Falls back to the grid snap when nothing aligns. Alt
-      // bypasses; Shift drops the grid snap for fine positioning.
-      const neighborX = modifiers.altKey
-        ? null
-        : snapLocalXToNeighbors({
-            wall: hit.wall,
-            localX: hit.localX,
-            width: node.width,
-            selfId: node.id as AnyNodeId,
-            nodes,
-          })
+      // bypasses alignment; Shift bypasses all snap.
+      const neighborX =
+        modifiers.altKey || modifiers.shiftKey
+          ? null
+          : snapLocalXToNeighbors({
+              wall: hit.wall,
+              localX: hit.localX,
+              width: node.width,
+              selfId: node.id as AnyNodeId,
+              nodes,
+            })
       const snappedLocalX = neighborX ?? (modifiers.shiftKey ? hit.localX : snapToHalf(hit.localX))
       const { clampedX, clampedY } = clampToWall(hit.wall, snappedLocalX, node.width, node.height)
 
diff --git a/packages/nodes/src/door/move-tool.tsx b/packages/nodes/src/door/move-tool.tsx
index 2062f464..ece90ca1 100644
--- a/packages/nodes/src/door/move-tool.tsx
+++ b/packages/nodes/src/door/move-tool.tsx
@@ -180,7 +180,8 @@ const MoveDoorTool: React.FC<{ node: DoorNode }> = ({ node: movingDoorNode }) =>
         rawLocalX: targetLocalX,
         width: movingDoorNode.width,
         candidates: alignmentCandidates,
-        bypass: event.nativeEvent?.altKey === true,
+        bypass: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
       const { clampedX, clampedY } = clampToWall(
         event.node,
diff --git a/packages/nodes/src/door/tool.tsx b/packages/nodes/src/door/tool.tsx
index c562a0f0..30913e50 100644
--- a/packages/nodes/src/door/tool.tsx
+++ b/packages/nodes/src/door/tool.tsx
@@ -123,7 +123,8 @@ const DoorTool: React.FC = () => {
         rawLocalX: event.localPosition[0],
         width,
         candidates: alignmentCandidates,
-        bypass: event.nativeEvent?.altKey === true,
+        bypass: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
 
       const { clampedX, clampedY } = clampToWall(event.node, localX, width, height)
@@ -176,7 +177,8 @@ const DoorTool: React.FC = () => {
         rawLocalX: event.localPosition[0],
         width,
         candidates: alignmentCandidates,
-        bypass: event.nativeEvent?.altKey === true,
+        bypass: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
 
       const { clampedX, clampedY } = clampToWall(event.node, localX, width, height)
@@ -268,7 +270,8 @@ const DoorTool: React.FC = () => {
         rawLocalX: event.localPosition[0],
         width: draftRef.current.width,
         candidates: alignmentCandidates,
-        bypass: event.nativeEvent?.altKey === true,
+        bypass: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
       const { clampedX, clampedY } = clampToWall(
         event.node,
diff --git a/packages/nodes/src/dormer/__tests__/geometry.test.ts b/packages/nodes/src/dormer/__tests__/geometry.test.ts
index 8094e05c..8774d200 100644
--- a/packages/nodes/src/dormer/__tests__/geometry.test.ts
+++ b/packages/nodes/src/dormer/__tests__/geometry.test.ts
@@ -1,4 +1,6 @@
 import { describe, expect, test } from 'bun:test'
+import { getRoofSegmentSurfaceY, type RoofSegmentNode } from '@pascal-app/core'
+import { getDormerExposedFaces } from '../csg-geometry'
 import {
   buildDormerGhostGeometry,
   dormerSupportsArch,
@@ -41,3 +43,74 @@ describe('windowShape predicates', () => {
     expect(dormerSupportsCornerRadii(DormerNode.parse({ windowShape: 'rectangle' }))).toBe(false)
   })
 })
+
+const hostSegment = (overrides?: Partial<RoofSegmentNode>): RoofSegmentNode =>
+  ({
+    object: 'node',
+    id: 'rseg_fixture',
+    type: 'roof-segment',
+    parentId: null,
+    visible: true,
+    metadata: {},
+    position: [0, 0, 0],
+    rotation: 0,
+    roofType: 'gable',
+    width: 8,
+    depth: 6,
+    wallHeight: 0.5,
+    pitch: 40,
+    wallThickness: 0.1,
+    deckThickness: 0.1,
+    overhang: 0.3,
+    shingleThickness: 0.05,
+    ...overrides,
+  }) as RoofSegmentNode
+
+// Default-dims dormer resting on the host surface at (x, z) — mirrors
+// `useDormerPlacement`, which anchors dormer-local Y=0 at the cursor's
+// surface height.
+const dormerAt = (segment: RoofSegmentNode, x: number, z: number, rotation = 0) =>
+  DormerNode.parse({ position: [x, getRoofSegmentSurfaceY(segment, x, z), z], rotation })
+
+describe('getDormerExposedFaces', () => {
+  test('default dormer mid-slope on the default 40° gable shows the down-slope window', () => {
+    const seg = hostSegment()
+    expect(getDormerExposedFaces(dormerAt(seg, 0, 1.5), seg)).toEqual({ front: true, back: false })
+  })
+
+  test('35° gable mid-slope stays exposed (centre datum, not window bottom)', () => {
+    const seg = hostSegment({ pitch: 35 })
+    expect(getDormerExposedFaces(dormerAt(seg, 0, 1.5), seg).front).toBe(true)
+  })
+
+  test('eave band: face hanging past the structural eave keeps the window (no plateau)', () => {
+    const seg = hostSegment()
+    expect(getDormerExposedFaces(dormerAt(seg, 0, 2.8), seg).front).toBe(true)
+  })
+
+  test('on the −Z slope the back face is the exposed one', () => {
+    const seg = hostSegment()
+    expect(getDormerExposedFaces(dormerAt(seg, 0, -1.5), seg)).toEqual({ front: false, back: true })
+  })
+
+  test('hip end-slope: face X feeds the max(fx, fz) profile', () => {
+    const seg = hostSegment({ roofType: 'hip' })
+    expect(getDormerExposedFaces(dormerAt(seg, 2.5, 0, Math.PI / 2), seg)).toEqual({
+      front: true,
+      back: false,
+    })
+  })
+
+  test('~10° pitch buries the window on both faces', () => {
+    const seg = hostSegment({ pitch: 10 })
+    expect(getDormerExposedFaces(dormerAt(seg, 0, 1.5), seg)).toEqual({ front: false, back: false })
+  })
+
+  test('a π yaw swaps which face is down-slope', () => {
+    const seg = hostSegment()
+    expect(getDormerExposedFaces(dormerAt(seg, 0, 1.5, Math.PI), seg)).toEqual({
+      front: false,
+      back: true,
+    })
+  })
+})
diff --git a/packages/nodes/src/dormer/csg-geometry.ts b/packages/nodes/src/dormer/csg-geometry.ts
index 27ebc162..a392d67a 100644
--- a/packages/nodes/src/dormer/csg-geometry.ts
+++ b/packages/nodes/src/dormer/csg-geometry.ts
@@ -1,7 +1,7 @@
 import {
   type DormerNode,
-  getActiveRoofHeight,
   getPitchFromActiveRoofHeight,
+  getRoofSegmentSurfaceY,
   ROOF_SHAPE_DEFAULTS,
   type RoofSegmentNode,
 } from '@pascal-app/core'
@@ -191,73 +191,61 @@ function createDormerWindowCutGeometry(
   return new THREE.BoxGeometry(w, h, depth)
 }
 
+// Exposure datum: a face shows its window when the window CENTER clears
+// the host's structural surface line (≥ half the window visible).
+// Gating on the window BOTTOM suppressed the default window on the
+// default 40° roof (break-even ≈ 36.7° pitch) and across the whole
+// lower-slope/overhang band. A partially buried window reads as a
+// window meeting the roof line: the host shingle shell occludes the
+// buried frame from outside (the dormer roof cut only clears the inner
+// cavity, 5cm short of the gable face), and the glass panes span the
+// full opening so the wall cut never reads as a see-through hole. The
+// margin only absorbs float noise at the grazing boundary — suppress
+// only when the window is truly unplaceable.
+const WINDOW_CENTER_MIN_CLEARANCE = 0.01
+
 /**
- * Which gable faces of a dormer have a *fully visible window opening*
- * (not clipped by the host roof slope). "front" = mesh-local +Z,
- * "back" = mesh-local −Z (after the +π/2 yaw bake for non-shed roofs).
+ * Which gable faces of a dormer have a visible window opening.
+ * "front" = mesh-local +Z, "back" = mesh-local −Z (after the +π/2 yaw
+ * bake for non-shed roofs).
  *
- * The criterion is window-bottom-above-slope, not wall-top-above-slope:
- * the dormer wall extends well below the window into the skirt that's
- * buried inside the roof, so checking just "does any wall poke above
- * the slope" is far too lenient — a dormer whose eave barely clears
- * the roof would pass even though the entire window (which sits inside
- * the skirt, well below the eave) is buried. Switching to the window
- * bottom collapses both the CSG window-cut decision (which calls into
- * this function in `generateDormerGeometry`) and the live render gate
- * (window-assembly.tsx) onto the right line: the window only renders
- * where it's actually visible from outside.
+ * Each face centre is lifted into segment-local X *and* Z (the yaw
+ * matters, and on hip hosts the end slopes fall along X) and compared
+ * against the host's canonical per-type surface line via
+ * `getRoofSegmentSurfaceY`, which extrapolates past the structural
+ * eave instead of plateauing at the wall top — a face hanging in free
+ * air past the eave keeps dropping. Gates both the CSG window-cut
+ * decision (`generateDormerGeometry`) and the live render
+ * (window-assembly.tsx).
  */
 export function getDormerExposedFaces(
   dormer: DormerNode,
   hostSegment: RoofSegmentNode,
 ): { front: boolean; back: boolean } {
   const halfDepth = dormer.depth / 2
-  const dormerZ = dormer.position[2] ?? 0
+  const dormerX = dormer.position[0] ?? 0
   const dormerY = dormer.position[1] ?? 0
+  const dormerZ = dormer.position[2] ?? 0
   const rot = dormer.rotation ?? 0
 
-  // Gable-face centres in segment-local Z (accounts for dormer yaw).
-  const frontZ = dormerZ + halfDepth * Math.cos(rot)
-  const backZ = dormerZ - halfDepth * Math.cos(rot)
+  // Gable-face centres in segment-local X/Z (accounts for dormer yaw).
+  const faceDX = halfDepth * Math.sin(rot)
+  const faceDZ = halfDepth * Math.cos(rot)
 
-  // Window bottom in dormer-local Y. Mirrors `getDormerSkirtWindowDims`
-  // so both functions read the same window position. The window sits
-  // in the skirt below the eave (dormer-local Y=0), so `centerY` is
-  // typically negative; subtracting half the window height lands us at
-  // the bottom edge.
+  // Window centre in segment-local Y. Mirrors `getDormerSkirtWindowDims`
+  // so both functions read the same window position: dormer-local Y=0
+  // sits at `dormer.position[1]` and the window centre sits in the
+  // skirt at -(skirtH / 2) + windowOffsetY.
   const skirtH = dormerSkirtHeight(dormer)
-  const winH = Math.max(0, dormer.windowHeight ?? 0)
-  const winOffsetY = dormer.windowOffsetY ?? 0
-  const windowCenterDormerY = -(skirtH / 2) + winOffsetY
-  const windowBottomDormerY = windowCenterDormerY - winH / 2
-  // Lift into segment-local Y: dormer-local Y=0 sits at `dormer.position[1]`.
-  const windowBottomSegY = dormerY + windowBottomDormerY
+  const windowCenterSegY = dormerY - skirtH / 2 + (dormer.windowOffsetY ?? 0)
 
-  const hostWh = hostSegment.wallHeight ?? 0.5
-  const hostRh = getActiveRoofHeight(hostSegment)
-  const hostDepth = hostSegment.depth ?? 4
+  const clears = (faceX: number, faceZ: number): boolean =>
+    windowCenterSegY - getRoofSegmentSurfaceY(hostSegment, faceX, faceZ) >
+    WINDOW_CENTER_MIN_CLEARANCE
 
-  const roofHeightAtZ = (segZ: number): number => {
-    const hostType = hostSegment.roofType ?? 'gable'
-    if (hostType === 'flat') return hostWh
-    if (hostType === 'shed') {
-      const t = Math.max(0, Math.min(1, (segZ + hostDepth / 2) / Math.max(hostDepth, 0.01)))
-      return hostWh + hostRh * (1 - t)
-    }
-    const halfD = Math.max(hostDepth / 2, 0.01)
-    const t = Math.max(0, Math.min(1, Math.abs(segZ) / halfD))
-    return hostWh + hostRh * (1 - t)
-  }
-
-  // A face is "exposed" only if the *window bottom* clears the host
-  // slope at that face's Z by a meaningful amount — borderline cases
-  // (slope grazing the window bottom) suppress the window so we don't
-  // render a partially-clipped frame poking out of the roof. 5cm
-  // matches the threshold the prior wall-top check used.
-  const minPokeOut = 0.05
   return {
-    front: windowBottomSegY - roofHeightAtZ(frontZ) > minPokeOut,
-    back: windowBottomSegY - roofHeightAtZ(backZ) > minPokeOut,
+    front: clears(dormerX + faceDX, dormerZ + faceDZ),
+    back: clears(dormerX - faceDX, dormerZ - faceDZ),
   }
 }
 
@@ -352,12 +340,15 @@ export function generateDormerGeometry(
       dormerBrushes.innerBrush,
       SUBTRACTION,
     ) as Brush
+    prepareBrushForCSG(hollowWall)
     const shinDeck = csgEvaluator.evaluate(
       dormerBrushes.shinSlab,
       dormerBrushes.deckSlab,
       ADDITION,
     ) as Brush
+    prepareBrushForCSG(shinDeck)
     dormerSolid = csgEvaluator.evaluate(shinDeck, hollowWall, ADDITION) as Brush
+    prepareBrushForCSG(dormerSolid)
     hollowWall.geometry.dispose()
     shinDeck.geometry.dispose()
 
@@ -376,7 +367,9 @@ export function generateDormerGeometry(
         hostBrushes.deckSlab,
         ADDITION,
       ) as Brush
+      prepareBrushForCSG(wallPlusDeck)
       hostSolid = csgEvaluator.evaluate(wallPlusDeck, hostBrushes.shinSlab, ADDITION) as Brush
+      prepareBrushForCSG(hostSolid)
       wallPlusDeck.geometry.dispose()
       hostBrushes.deckSlab.geometry.dispose()
       hostBrushes.shinSlab.geometry.dispose()
@@ -393,8 +386,9 @@ export function generateDormerGeometry(
       groundBoxGeo.addGroup(0, indexCount, 0)
       computeGeometryBoundsTree(groundBoxGeo)
       const groundBrush = new Brush(groundBoxGeo, roofCsgDummyMats[0])
-      groundBrush.updateMatrixWorld()
+      prepareBrushForCSG(groundBrush)
       const fullTrim = csgEvaluator.evaluate(hostSolid, groundBrush, ADDITION) as Brush
+      prepareBrushForCSG(fullTrim)
       hostSolid.geometry.dispose()
       groundBrush.geometry.dispose()
       hostSolid = fullTrim
@@ -416,6 +410,7 @@ export function generateDormerGeometry(
       prepareBrushForCSG(hostSolid)
 
       const trimmed = csgEvaluator.evaluate(dormerSolid, hostSolid, SUBTRACTION) as Brush
+      prepareBrushForCSG(trimmed)
       dormerSolid.geometry.dispose()
       hostSolid.geometry.dispose()
       hostSolid = null
@@ -447,8 +442,9 @@ export function generateDormerGeometry(
       cutGeo.addGroup(0, idxCount, 0)
       computeGeometryBoundsTree(cutGeo)
       const brush = new Brush(cutGeo, roofCsgDummyMats[0])
-      brush.updateMatrixWorld()
+      prepareBrushForCSG(brush)
       const result = csgEvaluator.evaluate(dormerSolid!, brush, SUBTRACTION) as Brush
+      prepareBrushForCSG(result)
       dormerSolid!.geometry.dispose()
       brush.geometry.dispose()
       dormerSolid = result
@@ -557,7 +553,7 @@ export function buildDormerCutShape(
     // ends up along mesh-(-Z) and the extrusion ends up along mesh-X.
     //
     // `getRoofSegmentBrushes`'s shed slope puts the peak at z=-d/2
-    // and the eave at z=+d/2 (matching the `roofHeightAtZ` helper).
+    // and the eave at z=+d/2 (matching `getRoofSegmentSurfaceY`).
     // After the +π/2 rotation, shape-X=+hd → mesh-Z=-hd, so place the
     // PEAK at shape-X=+hd and the EAVE at shape-X=-hd to keep the cut
     // aligned with the dormer body's actual slope direction.
diff --git a/packages/nodes/src/dormer/use-dormer-placement.ts b/packages/nodes/src/dormer/use-dormer-placement.ts
index 1d88fb43..5a628cb5 100644
--- a/packages/nodes/src/dormer/use-dormer-placement.ts
+++ b/packages/nodes/src/dormer/use-dormer-placement.ts
@@ -118,7 +118,7 @@ export function useDormerPlacement(opts: {
       const sx = Math.round(wx / DORMER_PLACEMENT_SNAP_M) * DORMER_PLACEMENT_SNAP_M
       const sz = Math.round(wz / DORMER_PLACEMENT_SNAP_M) * DORMER_PLACEMENT_SNAP_M
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
diff --git a/packages/nodes/src/dormer/window-assembly.tsx b/packages/nodes/src/dormer/window-assembly.tsx
index 12ca12a6..4c7734cb 100644
--- a/packages/nodes/src/dormer/window-assembly.tsx
+++ b/packages/nodes/src/dormer/window-assembly.tsx
@@ -118,12 +118,10 @@ const DormerWindowAssembly = ({
       // non-zero yaw needs to recompute exposure to know which gable
       // is now poking above the slope.
       node.rotation,
-      // Window position + height feed `getDormerExposedFaces` now that
-      // it's gating on window-bottom-above-slope (not wall-top-above-
-      // slope) — dragging the window down via inspector or the new
-      // window-height/offset handles must re-evaluate which gable
-      // still has a fully-visible opening.
-      node.windowHeight,
+      // The window's vertical placement feeds `getDormerExposedFaces`
+      // (gates on the window CENTER clearing the host slope) — dragging
+      // the window down via inspector or the offset handle must
+      // re-evaluate which gable still exposes the opening.
       node.windowOffsetY,
       node.wallSkirtHeight,
     ],
diff --git a/packages/nodes/src/eyebrow-vent/move-tool.tsx b/packages/nodes/src/eyebrow-vent/move-tool.tsx
index 036462d1..1d5d1696 100644
--- a/packages/nodes/src/eyebrow-vent/move-tool.tsx
+++ b/packages/nodes/src/eyebrow-vent/move-tool.tsx
@@ -67,7 +67,10 @@ export default function MoveEyebrowVentTool({ node }: { node: EyebrowVentNode })
 
       const sx = Math.round(target.localX * 20) / 20
       const sz = Math.round(target.localZ * 20) / 20
-      if (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz) {
+      if (
+        event.nativeEvent?.shiftKey !== true &&
+        (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz)
+      ) {
         triggerSFX('sfx:grid-snap')
         lastSnap = [sx, sz]
       }
diff --git a/packages/nodes/src/eyebrow-vent/tool.tsx b/packages/nodes/src/eyebrow-vent/tool.tsx
index 167f0188..14e4e673 100644
--- a/packages/nodes/src/eyebrow-vent/tool.tsx
+++ b/packages/nodes/src/eyebrow-vent/tool.tsx
@@ -14,7 +14,7 @@ import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useMemo, useRef, useState } from 'react'
 import * as THREE from 'three'
 import { resolveRoofSegmentHit } from '../shared/roof-segment-hit'
-import { getAnalyticalNormal, surfaceQuatFromNormal } from '../shared/roof-surface'
+import { getAnalyticalNormal, getDownSlopeYaw, surfaceQuatFromNormal } from '../shared/roof-surface'
 import { eyebrowVentDefinition } from './definition'
 import EyebrowVentPreview from './preview'
 
@@ -33,6 +33,7 @@ const EyebrowVentTool = () => {
   const [previewPos, setPreviewPos] = useState<[number, number, number] | null>(null)
   const [previewSurfaceQuat, setPreviewSurfaceQuat] = useState<THREE.Quaternion | null>(null)
   const [previewYaw, setPreviewYaw] = useState(0)
+  const [previewRotation, setPreviewRotation] = useState(0)
   const lastSnapRef = useRef<[number, number] | null>(null)
 
   const previewNode = useMemo(
@@ -41,9 +42,9 @@ const EyebrowVentTool = () => {
         ...eyebrowVentDefinition.defaults(),
         name: 'Eyebrow Vent',
         position: [0, 0, 0],
-        rotation: 0,
+        rotation: previewRotation,
       }),
-    [],
+    [previewRotation],
   )
 
   useEffect(() => {
@@ -65,7 +66,7 @@ const EyebrowVentTool = () => {
       const sx = Math.round(wx * 20) / 20
       const sz = Math.round(wz * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
@@ -76,6 +77,7 @@ const EyebrowVentTool = () => {
       const normal = getAnalyticalNormal(hit.localX, hit.localZ, hit.segment)
       setPreviewSurfaceQuat(surfaceQuatFromNormal(normal, new THREE.Quaternion()))
       setPreviewYaw((event.node.rotation ?? 0) + (hit.segment.rotation ?? 0))
+      setPreviewRotation(getDownSlopeYaw(hit.localX, hit.localZ, hit.segment))
       setPreviewPos(worldToBuildingLocal(wx, wy, wz))
       event.stopPropagation()
     }
@@ -95,7 +97,7 @@ const EyebrowVentTool = () => {
         name: 'Eyebrow Vent',
         roofSegmentId: hit.segment.id,
         position: [hit.localX, hit.localY, hit.localZ],
-        rotation: 0,
+        rotation: getDownSlopeYaw(hit.localX, hit.localZ, hit.segment),
       })
       state.createNode(vent, hit.segment.id as AnyNodeId)
       state.dirtyNodes.add(hit.segment.id as AnyNodeId)
diff --git a/packages/nodes/src/fence/actions/move-endpoint.ts b/packages/nodes/src/fence/actions/move-endpoint.ts
index d1a6d516..f53a3651 100644
--- a/packages/nodes/src/fence/actions/move-endpoint.ts
+++ b/packages/nodes/src/fence/actions/move-endpoint.ts
@@ -14,7 +14,6 @@ import {
   isSegmentLongEnough,
   snapFenceDraftPoint,
   useAlignmentGuides,
-  WALL_FINE_GRID_STEP,
 } from '@pascal-app/editor'
 
 /**
@@ -165,14 +164,13 @@ export const moveFenceEndpointDragAction: DragAction<MoveFenceEndpointCtx, MoveF
     preview: (ctx, point, modifiers) => {
       const planPoint: FencePlanPoint = [point[0], point[1]]
       // Endpoint move = grid snap only; the 45°-from-start angle snap
-      // is draft-only. Shift switches to the fine grid step for
-      // precision, mirroring the wall convention.
+      // is draft-only. Shift is a hard snap bypass.
       const snapped = snapFenceDraftPoint({
         point: planPoint,
         walls: ctx.levelWalls,
         fences: ctx.levelFences,
         ignoreFenceIds: [ctx.fenceId as string],
-        step: modifiers.shift ? WALL_FINE_GRID_STEP : undefined,
+        bypassSnap: modifiers.shift,
       })
 
       // Figma-style alignment: nudge the dragged endpoint onto another wall /
@@ -180,7 +178,7 @@ export const moveFenceEndpointDragAction: DragAction<MoveFenceEndpointCtx, MoveF
       // guide. The resolver connects to the NEAREST real anchor, so the dot
       // always sits on an actual point. Alt is reserved for detach.
       let aligned = snapped
-      if (ctx.alignCandidates.length > 0) {
+      if (!modifiers.shift && ctx.alignCandidates.length > 0) {
         const ar = resolveAlignment({
           moving: [{ nodeId: ctx.fenceId as string, kind: 'corner', x: snapped[0], z: snapped[1] }],
           candidates: ctx.alignCandidates,
@@ -190,6 +188,8 @@ export const moveFenceEndpointDragAction: DragAction<MoveFenceEndpointCtx, MoveF
           aligned = [snapped[0] + ar.snap.dx, snapped[1] + ar.snap.dz]
         }
         useAlignmentGuides.getState().set(ar.guides)
+      } else {
+        useAlignmentGuides.getState().clear()
       }
 
       const nextStart = ctx.endpoint === 'start' ? aligned : ctx.fixedPoint
diff --git a/packages/nodes/src/fence/curve-tool.tsx b/packages/nodes/src/fence/curve-tool.tsx
index 38631e02..0d03b18d 100644
--- a/packages/nodes/src/fence/curve-tool.tsx
+++ b/packages/nodes/src/fence/curve-tool.tsx
@@ -89,11 +89,12 @@ export const CurveFenceTool: React.FC<{ node: FenceNode }> = ({ node }) => {
     }
 
     const onGridMove = (event: GridEvent) => {
+      const bypassSnap = shiftPressedRef.current || event.nativeEvent?.shiftKey === true
       const snapStep = getSegmentGridStep()
-      const localX = shiftPressedRef.current
+      const localX = bypassSnap
         ? event.localPosition[0]
         : snapScalarToGrid(event.localPosition[0], snapStep)
-      const localZ = shiftPressedRef.current
+      const localZ = bypassSnap
         ? event.localPosition[2]
         : snapScalarToGrid(event.localPosition[2], snapStep)
 
@@ -101,7 +102,7 @@ export const CurveFenceTool: React.FC<{ node: FenceNode }> = ({ node }) => {
         (localX - chord.midpoint.x) * chord.normal.x +
         (localZ - chord.midpoint.y) * chord.normal.y
       )
-      const snappedOffset = shiftPressedRef.current
+      const snappedOffset = bypassSnap
         ? offsetFromMidpoint
         : snapScalarToGrid(offsetFromMidpoint, snapStep)
       const nextCurveOffset = normalizeWallCurveOffset(
@@ -110,6 +111,7 @@ export const CurveFenceTool: React.FC<{ node: FenceNode }> = ({ node }) => {
       )
 
       if (
+        !bypassSnap &&
         previousCurveOffsetRef.current !== null &&
         nextCurveOffset !== previousCurveOffsetRef.current
       ) {
diff --git a/packages/nodes/src/fence/definition.ts b/packages/nodes/src/fence/definition.ts
index 36fe97bc..b01da5e2 100644
--- a/packages/nodes/src/fence/definition.ts
+++ b/packages/nodes/src/fence/definition.ts
@@ -223,7 +223,7 @@ export const fenceDefinition: NodeDefinition<typeof FenceNode> = {
 
   toolHints: [
     { key: 'Left click', label: 'Set fence start / end' },
-    { key: 'Shift', label: 'Allow non-45° angles' },
+    { key: 'Shift', label: 'Free angle (no 15° snap)' },
     { key: 'Esc', label: 'Cancel' },
   ],
 
diff --git a/packages/nodes/src/fence/floorplan-affordances.ts b/packages/nodes/src/fence/floorplan-affordances.ts
index 2843e17a..6236a419 100644
--- a/packages/nodes/src/fence/floorplan-affordances.ts
+++ b/packages/nodes/src/fence/floorplan-affordances.ts
@@ -20,7 +20,6 @@ import {
   snapFenceDraftPoint,
   snapScalarToGrid,
   useAlignmentGuides,
-  WALL_FINE_GRID_STEP,
   WALL_GRID_STEP,
 } from '@pascal-app/editor'
 
@@ -159,16 +158,15 @@ export const fenceMoveEndpointAffordance: FloorplanAffordance<FenceNode> = {
         const sceneNodes = useScene.getState().nodes
         const { walls: nextWalls, fences: nextFences } = collectLevel(sceneNodes, parentId)
         // Endpoint move = grid snap only; the 45°-from-start angle
-        // snap is draft-only. Shift switches to the fine grid step for
-        // precision, matching the 3D fence endpoint action.
-        const worldStep = modifiers.shiftKey ? WALL_FINE_GRID_STEP : WALL_GRID_STEP
+        // snap is draft-only. Shift bypasses grid, magnetic, and alignment snap.
         const snapped = snapFenceDraftPoint({
           point: planPoint as FencePlanPoint,
           walls: nextWalls,
           fences: nextFences,
           ignoreFenceIds: [node.id],
-          step: modifiers.shiftKey ? WALL_FINE_GRID_STEP : undefined,
-          gridSnap: (p) => snapBuildingLocalToWorldGrid(p, worldStep) as FencePlanPoint,
+          bypassSnap: modifiers.shiftKey,
+          magnetic: !modifiers.shiftKey,
+          gridSnap: (p) => snapBuildingLocalToWorldGrid(p, WALL_GRID_STEP) as FencePlanPoint,
         })
         // Figma-style alignment on the dragged endpoint — snaps it onto
         // another object's edge / wall face and publishes a guide, matching
@@ -176,6 +174,7 @@ export const fenceMoveEndpointAffordance: FloorplanAffordance<FenceNode> = {
         // siblings (which cascade with the endpoint) are excluded from the
         // candidate pool. Alt is reserved for detach here, NOT bypass.
         const aligned = alignFloorplanDraftPoint(snapped, {
+          bypass: modifiers.shiftKey,
           excludeIds: [node.id, ...linkedOriginals.map((l) => l.id)],
         }) as FencePlanPoint
         const nextStart = endpoint === 'start' ? aligned : fixedPoint
diff --git a/packages/nodes/src/fence/move-endpoint-tool.tsx b/packages/nodes/src/fence/move-endpoint-tool.tsx
index c5bc0a6e..c57be884 100644
--- a/packages/nodes/src/fence/move-endpoint-tool.tsx
+++ b/packages/nodes/src/fence/move-endpoint-tool.tsx
@@ -1,6 +1,13 @@
 'use client'
 
-import { type FenceNode, getWallCurveLength, useScene, type WallNode } from '@pascal-app/core'
+import {
+  emitter,
+  type FenceNode,
+  type GridEvent,
+  getWallCurveLength,
+  useScene,
+  type WallNode,
+} from '@pascal-app/core'
 import {
   CursorSphere,
   type FencePlanPoint,
@@ -121,13 +128,43 @@ export const MoveFenceEndpointTool: React.FC<{ target: MovingFenceEndpoint }> =
   const movingPoint = endpoint === 'start' ? liveStart : liveEnd
 
   // Ticker SFX on each grid-snap step, mirroring the wall endpoint tool.
-  // The action snaps the point before writing to the scene, so `movingPoint`
-  // only changes in discrete grid steps — the right cadence for the click.
-  // First tick just seeds the ref (no sound on mount).
+  // First tick just seeds the ref (no sound on mount). The drag action receives
+  // the Shift modifier through grid events, so mirror that modifier here to
+  // avoid playing grid ticks while snap is bypassed.
   const previousGridPosRef = useRef<FencePlanPoint | null>(null)
+  const shiftPressedRef = useRef(false)
+  useEffect(() => {
+    const onGridMove = (event: GridEvent) => {
+      shiftPressedRef.current = event.nativeEvent?.shiftKey === true
+    }
+    const onKeyDown = (event: KeyboardEvent) => {
+      if (event.key === 'Shift') shiftPressedRef.current = true
+    }
+    const onKeyUp = (event: KeyboardEvent) => {
+      if (event.key === 'Shift') shiftPressedRef.current = false
+    }
+    const onBlur = () => {
+      shiftPressedRef.current = false
+    }
+    emitter.on('grid:move', onGridMove)
+    window.addEventListener('keydown', onKeyDown)
+    window.addEventListener('keyup', onKeyUp)
+    window.addEventListener('blur', onBlur)
+    return () => {
+      emitter.off('grid:move', onGridMove)
+      window.removeEventListener('keydown', onKeyDown)
+      window.removeEventListener('keyup', onKeyUp)
+      window.removeEventListener('blur', onBlur)
+    }
+  }, [])
+
   useEffect(() => {
     const prev = previousGridPosRef.current
-    if (prev && (prev[0] !== movingPoint[0] || prev[1] !== movingPoint[1])) {
+    if (
+      !shiftPressedRef.current &&
+      prev &&
+      (prev[0] !== movingPoint[0] || prev[1] !== movingPoint[1])
+    ) {
       triggerSFX('sfx:grid-snap')
     }
     previousGridPosRef.current = movingPoint
diff --git a/packages/nodes/src/fence/move-tool.tsx b/packages/nodes/src/fence/move-tool.tsx
index 2831c2dc..5ca806aa 100644
--- a/packages/nodes/src/fence/move-tool.tsx
+++ b/packages/nodes/src/fence/move-tool.tsx
@@ -193,14 +193,17 @@ export const MoveFenceTool: React.FC<{ node: FenceNode }> = ({ node }) => {
     }
 
     const onGridMove = (event: GridEvent) => {
+      const bypassSnap = event.nativeEvent?.shiftKey === true
       const [localX, localZ] = snapFenceDraftPoint({
         point: [event.localPosition[0], event.localPosition[2]],
         walls: levelWalls,
         fences: levelFences,
         ignoreFenceIds: [fenceId],
+        bypassSnap,
       })
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (localX !== previousGridPosRef.current[0] || localZ !== previousGridPosRef.current[1])
       ) {
diff --git a/packages/nodes/src/fence/tool.tsx b/packages/nodes/src/fence/tool.tsx
index 0101344c..17de5cd1 100644
--- a/packages/nodes/src/fence/tool.tsx
+++ b/packages/nodes/src/fence/tool.tsx
@@ -30,7 +30,7 @@ import {
   triggerSFX,
   useAlignmentGuides,
   useEditor,
-  WALL_FINE_GRID_STEP,
+  useSegmentDraftChain,
 } from '@pascal-app/editor'
 import { getSceneTheme, useViewer } from '@pascal-app/viewer'
 import { Html } from '@react-three/drei'
@@ -485,6 +485,7 @@ export const FenceTool: React.FC = () => {
       buildingState.current = 0
       previewRef.current.visible = false
       setDraftMeasurement(null)
+      useSegmentDraftChain.getState().clear('fence')
       useAlignmentGuides.getState().clear()
     }
 
@@ -492,20 +493,29 @@ export const FenceTool: React.FC = () => {
       if (!(cursorRef.current && previewRef.current)) return
       const { walls, fences } = getCurrentLevelElements()
       const localPoint: FencePlanPoint = [event.localPosition[0], event.localPosition[2]]
-      // Default = active grid step; Shift switches to the fine step
-      // (0.05m). No 45° angle snap — see `wall/tool.tsx` for rationale.
-      const step = shiftPressed.current ? WALL_FINE_GRID_STEP : undefined
-      const bypassAlign = event.nativeEvent?.altKey === true
+      // While drafting, the segment locks to 15° rays from its start
+      // unless Shift is held. Shift also bypasses grid and magnetic snap.
+      const bypassSnap = shiftPressed.current || event.nativeEvent?.shiftKey === true
+      const bypassAlign = event.nativeEvent?.altKey === true || bypassSnap
 
       if (buildingState.current === 1) {
+        const angleLocked = !bypassSnap
         const snappedLocal = alignPoint(
-          snapFenceDraftPoint({ point: localPoint, walls, fences, step }),
-          bypassAlign,
+          snapFenceDraftPoint({
+            point: localPoint,
+            walls,
+            fences,
+            start: angleLocked ? [startingPoint.current.x, startingPoint.current.z] : undefined,
+            angleSnap: angleLocked,
+            bypassSnap,
+          }),
+          bypassAlign || angleLocked,
         )
         endingPoint.current.set(snappedLocal[0], event.localPosition[1], snappedLocal[1])
         cursorRef.current.position.copy(endingPoint.current)
         const currentFenceEnd: FencePlanPoint = [snappedLocal[0], snappedLocal[1]]
         if (
+          !bypassSnap &&
           previousFenceEnd &&
           (currentFenceEnd[0] !== previousFenceEnd[0] || currentFenceEnd[1] !== previousFenceEnd[1])
         ) {
@@ -532,7 +542,7 @@ export const FenceTool: React.FC = () => {
         )
       } else {
         const snappedPoint = alignPoint(
-          snapFenceDraftPoint({ point: localPoint, walls, fences, step }),
+          snapFenceDraftPoint({ point: localPoint, walls, fences, bypassSnap }),
           bypassAlign,
         )
         cursorRef.current.position.set(snappedPoint[0], event.localPosition[1], snappedPoint[1])
@@ -548,12 +558,12 @@ export const FenceTool: React.FC = () => {
 
       const { walls, fences } = getCurrentLevelElements()
       const localClick: FencePlanPoint = [event.localPosition[0], event.localPosition[2]]
-      const clickStep = shiftPressed.current ? WALL_FINE_GRID_STEP : undefined
-      const bypassAlign = event.nativeEvent?.altKey === true
+      const bypassSnap = shiftPressed.current || event.nativeEvent?.shiftKey === true
+      const bypassAlign = event.nativeEvent?.altKey === true || bypassSnap
 
       if (buildingState.current === 0) {
         const snappedStart = alignPoint(
-          snapFenceDraftPoint({ point: localClick, walls, fences, step: clickStep }),
+          snapFenceDraftPoint({ point: localClick, walls, fences, bypassSnap }),
           bypassAlign,
         )
         startingPoint.current.set(snappedStart[0], event.localPosition[1], snappedStart[1])
@@ -563,9 +573,17 @@ export const FenceTool: React.FC = () => {
         previewRef.current.visible = true
         setDraftMeasurement(null)
       } else {
+        const angleLocked = !bypassSnap
         const snappedEnd = alignPoint(
-          snapFenceDraftPoint({ point: localClick, walls, fences, step: clickStep }),
-          bypassAlign,
+          snapFenceDraftPoint({
+            point: localClick,
+            walls,
+            fences,
+            start: angleLocked ? [startingPoint.current.x, startingPoint.current.z] : undefined,
+            angleSnap: angleLocked,
+            bypassSnap,
+          }),
+          bypassAlign || angleLocked,
         )
         const dx = snappedEnd[0] - startingPoint.current.x
         const dz = snappedEnd[1] - startingPoint.current.z
@@ -582,6 +600,10 @@ export const FenceTool: React.FC = () => {
         useAlignmentGuides.getState().clear()
 
         const nextStart = createdFence.end
+        // Publish the resolved chain start so the 2D floor-plan draft
+        // chains its next segment from the same point (its own snap
+        // pipeline can resolve a slightly different endpoint).
+        useSegmentDraftChain.getState().setChainStart('fence', [nextStart[0], nextStart[1]])
         startingPoint.current.set(nextStart[0], event.localPosition[1], nextStart[1])
         endingPoint.current.copy(startingPoint.current)
         cursorRef.current?.position.copy(startingPoint.current)
@@ -599,6 +621,12 @@ export const FenceTool: React.FC = () => {
       if (e.key === 'Shift') shiftPressed.current = false
     }
 
+    // Cmd-tabbing away mid-draft never delivers the keyup — reset so the
+    // angle lock isn't stuck off when focus returns.
+    const onBlur = () => {
+      shiftPressed.current = false
+    }
+
     const onCancel = () => {
       if (buildingState.current === 1) {
         markToolCancelConsumed()
@@ -611,6 +639,7 @@ export const FenceTool: React.FC = () => {
     emitter.on('tool:cancel', onCancel)
     window.addEventListener('keydown', onKeyDown)
     window.addEventListener('keyup', onKeyUp)
+    window.addEventListener('blur', onBlur)
 
     return () => {
       emitter.off('grid:move', onGridMove)
@@ -618,6 +647,8 @@ export const FenceTool: React.FC = () => {
       emitter.off('tool:cancel', onCancel)
       window.removeEventListener('keydown', onKeyDown)
       window.removeEventListener('keyup', onKeyUp)
+      window.removeEventListener('blur', onBlur)
+      useSegmentDraftChain.getState().clear('fence')
       useAlignmentGuides.getState().clear()
     }
   }, [unit])
diff --git a/packages/nodes/src/gutter/geometry.ts b/packages/nodes/src/gutter/geometry.ts
index f030cbbc..08ce9ab3 100644
--- a/packages/nodes/src/gutter/geometry.ts
+++ b/packages/nodes/src/gutter/geometry.ts
@@ -225,6 +225,7 @@ export function buildGutterGeometry(
       const drillBrush = new Brush(drill)
       prepareBrushForCSG(drillBrush)
       const next = csgEvaluator.evaluate(workingBrush, drillBrush, SUBTRACTION) as Brush
+      prepareBrushForCSG(next)
       // Free the previous step's intermediate result (but not `merged`,
       // which is disposed once below).
       if (workingBrush.geometry !== merged) workingBrush.geometry.dispose()
diff --git a/packages/nodes/src/gutter/move-tool.tsx b/packages/nodes/src/gutter/move-tool.tsx
index 57295ba0..32780993 100644
--- a/packages/nodes/src/gutter/move-tool.tsx
+++ b/packages/nodes/src/gutter/move-tool.tsx
@@ -97,7 +97,10 @@ export default function MoveGutterTool({ node }: { node: GutterNode }) {
 
       const sx = Math.round(snap.eaveX * 20) / 20
       const sz = Math.round(snap.eaveZ * 20) / 20
-      if (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz) {
+      if (
+        event.nativeEvent?.shiftKey !== true &&
+        (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz)
+      ) {
         triggerSFX('sfx:grid-snap')
         lastSnap = [sx, sz]
       }
diff --git a/packages/nodes/src/gutter/tool.tsx b/packages/nodes/src/gutter/tool.tsx
index f2066e09..1258519c 100644
--- a/packages/nodes/src/gutter/tool.tsx
+++ b/packages/nodes/src/gutter/tool.tsx
@@ -83,7 +83,7 @@ const GutterTool = () => {
       const sx = Math.round(snap.eaveX * 20) / 20
       const sz = Math.round(snap.eaveZ * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
diff --git a/packages/nodes/src/item/definition.ts b/packages/nodes/src/item/definition.ts
index 2f9dc6fe..9224d701 100644
--- a/packages/nodes/src/item/definition.ts
+++ b/packages/nodes/src/item/definition.ts
@@ -22,10 +22,10 @@ const ROTATE_RING_OFFSET = 0.06
 // Whole-item rotation handle — the two-headed curved arrow. `arc-resize`
 // does the angular drag math (raycasts a horizontal plane at the gizmo's
 // Y, measures cursor bearing around the item's local origin, returns the
-// delta). Holding Shift snaps to 15° increments (handled generically in
-// node-arrow-handles for any `shape: 'rotate'`), matching the R/T rotate
-// step for placed items. Item rotation is stored as `[x, y, z]`; only the
-// Y component turns.
+// delta). Rotation snaps to 15° increments by default; holding Shift
+// bypasses that snap (handled generically in node-arrow-handles for any
+// `shape: 'rotate'`), matching the R/T rotate step for placed items. Item
+// rotation is stored as `[x, y, z]`; only the Y component turns.
 function itemRotateHandle(): HandleDescriptor<ItemNodeType> {
   return {
     kind: 'arc-resize',
diff --git a/packages/nodes/src/item/floorplan-move.ts b/packages/nodes/src/item/floorplan-move.ts
index d8747045..49f14faf 100644
--- a/packages/nodes/src/item/floorplan-move.ts
+++ b/packages/nodes/src/item/floorplan-move.ts
@@ -211,16 +211,17 @@ function buildWallItemSession(
 
       // Figma-style along-wall alignment (edge-to-edge with other openings /
       // wall items / wall ends), winning over the 0.5m grid snap; falls back
-      // to grid when nothing aligns. Alt bypasses; Shift drops the grid snap.
-      const neighborX = modifiers.altKey
-        ? null
-        : snapLocalXToNeighbors({
-            wall: hit.wall,
-            localX: hit.localX,
-            width,
-            selfId: node.id as AnyNodeId,
-            nodes,
-          })
+      // to grid when nothing aligns. Alt bypasses alignment; Shift bypasses all snap.
+      const neighborX =
+        modifiers.altKey || modifiers.shiftKey
+          ? null
+          : snapLocalXToNeighbors({
+              wall: hit.wall,
+              localX: hit.localX,
+              width,
+              selfId: node.id as AnyNodeId,
+              nodes,
+            })
       const step = useEditor.getState().gridSnapStep
       const snappedLocalX =
         neighborX ?? (modifiers.shiftKey ? hit.localX : Math.round(hit.localX / step) * step)
@@ -286,7 +287,7 @@ function buildFloorItemSession(
           rotationY,
         ),
         candidates,
-        { bypass: modifiers.altKey },
+        { bypass: modifiers.altKey || modifiers.shiftKey },
       )
 
       const sourceY = node.position[1]
diff --git a/packages/nodes/src/ridge-vent/move-tool.tsx b/packages/nodes/src/ridge-vent/move-tool.tsx
index e72fa2df..62752d6f 100644
--- a/packages/nodes/src/ridge-vent/move-tool.tsx
+++ b/packages/nodes/src/ridge-vent/move-tool.tsx
@@ -80,7 +80,10 @@ export default function MoveRidgeVentTool({ node }: { node: RidgeVentNode }) {
 
       const sx = Math.round(target.localX * 20) / 20
       const sz = Math.round(target.localZ * 20) / 20
-      if (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz) {
+      if (
+        event.nativeEvent?.shiftKey !== true &&
+        (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz)
+      ) {
         triggerSFX('sfx:grid-snap')
         lastSnap = [sx, sz]
       }
diff --git a/packages/nodes/src/ridge-vent/tool.tsx b/packages/nodes/src/ridge-vent/tool.tsx
index 2ef682fc..9a1a08eb 100644
--- a/packages/nodes/src/ridge-vent/tool.tsx
+++ b/packages/nodes/src/ridge-vent/tool.tsx
@@ -88,7 +88,7 @@ const RidgeVentTool = () => {
       const sx = Math.round(ridgeWorld[0] * 20) / 20
       const sz = Math.round(ridgeWorld[2] * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
diff --git a/packages/nodes/src/roof-segment/floorplan-affordances.ts b/packages/nodes/src/roof-segment/floorplan-affordances.ts
index aa50683a..32212306 100644
--- a/packages/nodes/src/roof-segment/floorplan-affordances.ts
+++ b/packages/nodes/src/roof-segment/floorplan-affordances.ts
@@ -79,11 +79,12 @@ export const roofSegmentResizeAffordance: FloorplanAffordance<RoofSegmentNode> =
 
     return {
       affectedIds: [segmentId],
-      apply({ planPoint }) {
+      apply({ planPoint, modifiers }) {
         const currentLocal = projectLocalAxis(planPoint[0], planPoint[1])
         const delta = (currentLocal - initialLocal) * side
         const rawValue = initialValue + 2 * delta
-        const snappedValue = gridSnapStep > 0 ? snapScalar(rawValue, gridSnapStep) : rawValue
+        const snappedValue =
+          !modifiers.shiftKey && gridSnapStep > 0 ? snapScalar(rawValue, gridSnapStep) : rawValue
         const newValue = Math.max(MIN_ROOF_DIM, snappedValue)
         lastValue = newValue
         useScene
diff --git a/packages/nodes/src/shared/floor-placement.ts b/packages/nodes/src/shared/floor-placement.ts
index fa672f7b..5c2abe3d 100644
--- a/packages/nodes/src/shared/floor-placement.ts
+++ b/packages/nodes/src/shared/floor-placement.ts
@@ -36,6 +36,7 @@ type FloorPlacementAlignmentArgs = {
   gridStep: number
   candidates: Parameters<typeof resolveAlignment>[0]['candidates']
   bypassAlignment?: boolean
+  bypassGrid?: boolean
   rotationY?: number
 }
 
@@ -45,18 +46,23 @@ export function getLevelLocalSnappedPosition(
   levelId: string,
   event: FloorPlacementClickTriggerEvent,
   gridStep: number,
+  bypassGrid = false,
 ): [number, number, number] {
   const levelObject = sceneRegistry.nodes.get(levelId)
   if (!levelObject) {
     const rawPoint = 'node' in event ? event.position : event.localPosition
-    const [sx, sz] = snapPointToGrid([rawPoint[0], rawPoint[2]], gridStep)
+    const [sx, sz] = bypassGrid
+      ? [rawPoint[0], rawPoint[2]]
+      : snapPointToGrid([rawPoint[0], rawPoint[2]], gridStep)
     return [sx, 0, sz]
   }
 
   worldVector.set(event.position[0], event.position[1], event.position[2])
   levelObject.updateWorldMatrix(true, false)
   levelObject.worldToLocal(worldVector)
-  const [sx, sz] = snapPointToGrid([worldVector.x, worldVector.z], gridStep)
+  const [sx, sz] = bypassGrid
+    ? [worldVector.x, worldVector.z]
+    : snapPointToGrid([worldVector.x, worldVector.z], gridStep)
   return [sx, 0, sz]
 }
 
@@ -67,9 +73,10 @@ export function resolveAlignedFloorPlacement({
   gridStep,
   candidates,
   bypassAlignment = false,
+  bypassGrid = false,
   rotationY = 0,
 }: FloorPlacementAlignmentArgs) {
-  const [sx, sz] = snapPointToGrid([rawX, rawZ], gridStep)
+  const [sx, sz] = bypassGrid ? [rawX, rawZ] : snapPointToGrid([rawX, rawZ], gridStep)
   let ax = sx
   let az = sz
 
diff --git a/packages/nodes/src/shared/move-roof-tool.tsx b/packages/nodes/src/shared/move-roof-tool.tsx
index 3c95163f..d3c762d6 100644
--- a/packages/nodes/src/shared/move-roof-tool.tsx
+++ b/packages/nodes/src/shared/move-roof-tool.tsx
@@ -293,6 +293,7 @@ export const MoveRoofTool: React.FC<{
         point: [event.localPosition[0], event.localPosition[2]],
         walls: levelWalls,
         fences: levelFences,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
       const [rawGridX, , rawGridZ] = localToWorldPoint(snappedLocal, y)
       const [rawLocalX, rawLocalZ] = computeLocal(
@@ -312,12 +313,17 @@ export const MoveRoofTool: React.FC<{
       let [localX, localZ] = resolved.point
 
       if (alignTopLevel) {
-        const aligned = alignLocalPoint(localX, localZ, event.nativeEvent?.altKey === true)
+        const aligned = alignLocalPoint(
+          localX,
+          localZ,
+          event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        )
         localX = aligned[0]
         localZ = aligned[1]
       }
 
       if (
+        event.nativeEvent?.shiftKey !== true &&
         previousGridPosRef.current &&
         (localX !== previousGridPosRef.current[0] || localZ !== previousGridPosRef.current[1])
       ) {
diff --git a/packages/nodes/src/shared/placeholder-geometry.ts b/packages/nodes/src/shared/placeholder-geometry.ts
index 52ce511c..c3c2cb34 100644
--- a/packages/nodes/src/shared/placeholder-geometry.ts
+++ b/packages/nodes/src/shared/placeholder-geometry.ts
@@ -24,6 +24,7 @@ export function createPlaceholderGeometry(groupCount = 0): BufferGeometry {
   geometry.setAttribute('position', new Float32BufferAttribute(new Float32Array(9), 3))
   geometry.setAttribute('normal', new Float32BufferAttribute(new Float32Array(9), 3))
   geometry.setAttribute('uv', new Float32BufferAttribute(new Float32Array(6), 2))
+  geometry.setAttribute('uv2', new Float32BufferAttribute(new Float32Array(6), 2))
   for (let group = 0; group < groupCount; group++) {
     geometry.addGroup(0, 0, group)
   }
diff --git a/packages/nodes/src/shared/polygon-centroid-move.ts b/packages/nodes/src/shared/polygon-centroid-move.ts
index 9684ea05..c6dd78e0 100644
--- a/packages/nodes/src/shared/polygon-centroid-move.ts
+++ b/packages/nodes/src/shared/polygon-centroid-move.ts
@@ -104,7 +104,7 @@ export function createPolygonCentroidMoveTarget(args: {
       let dx = target[0] - originalCenter[0]
       let dz = target[1] - originalCenter[1]
 
-      if (!modifiers.altKey && candidates.length > 0) {
+      if (!(modifiers.altKey || modifiers.shiftKey) && candidates.length > 0) {
         const result = resolveAlignment({
           moving: polygonAnchors(id, translatePolygon(originalPolygon, dx, dz)),
           candidates,
diff --git a/packages/nodes/src/shared/roof-surface.test.ts b/packages/nodes/src/shared/roof-surface.test.ts
new file mode 100644
index 00000000..1b5157df
--- /dev/null
+++ b/packages/nodes/src/shared/roof-surface.test.ts
@@ -0,0 +1,43 @@
+import { describe, expect, test } from 'bun:test'
+import type { RoofSegmentNode } from '@pascal-app/core'
+import { getDownSlopeYaw } from './roof-surface'
+
+const fixtureSegment = (overrides?: Partial<RoofSegmentNode>): RoofSegmentNode =>
+  ({
+    object: 'node',
+    id: 'rseg_fixture',
+    type: 'roof-segment',
+    parentId: null,
+    visible: true,
+    metadata: {},
+    position: [0, 0, 0],
+    rotation: 0,
+    roofType: 'gable',
+    width: 8,
+    depth: 6,
+    wallHeight: 2.5,
+    pitch: (Math.atan2(2, 3) * 180) / Math.PI,
+    wallThickness: 0.1,
+    deckThickness: 0.1,
+    overhang: 0.3,
+    shingleThickness: 0.05,
+    ...overrides,
+  }) as RoofSegmentNode
+
+describe('getDownSlopeYaw', () => {
+  test('gable +z face: local +z already points down-slope (yaw 0)', () => {
+    expect(getDownSlopeYaw(0, 1, fixtureSegment())).toBeCloseTo(0)
+  })
+  test('gable −z face: half-turn so +z faces the −z eave (yaw π)', () => {
+    expect(getDownSlopeYaw(0, -1, fixtureSegment())).toBeCloseTo(Math.PI)
+  })
+  test('hip +x face yaws +π/2', () => {
+    expect(getDownSlopeYaw(2, 0, fixtureSegment({ roofType: 'hip' }))).toBeCloseTo(Math.PI / 2)
+  })
+  test('hip −x face yaws −π/2', () => {
+    expect(getDownSlopeYaw(-2, 0, fixtureSegment({ roofType: 'hip' }))).toBeCloseTo(-Math.PI / 2)
+  })
+  test('flat segment has no down-slope direction (yaw 0)', () => {
+    expect(getDownSlopeYaw(0, 0, fixtureSegment({ roofType: 'flat' }))).toBe(0)
+  })
+})
diff --git a/packages/nodes/src/shared/roof-surface.ts b/packages/nodes/src/shared/roof-surface.ts
index 9a1368b3..f60278cd 100644
--- a/packages/nodes/src/shared/roof-surface.ts
+++ b/packages/nodes/src/shared/roof-surface.ts
@@ -137,3 +137,15 @@ export function surfaceQuatFromNormal(normal: THREE.Vector3, out: THREE.Quaterni
   const m = new THREE.Matrix4().makeBasis(right, normal, forward)
   return out.setFromRotationMatrix(m)
 }
+
+// Yaw (about the surface normal, composed AFTER `surfaceQuatFromNormal`)
+// that points the node's local +Z down the slope. The analytical normals
+// are axis-aligned (n.x or n.z is 0), and in the +X-projected basis above
+// the down-slope direction decomposes to atan2(n.x · n.y, n.z): +Z face
+// → 0, −Z → π, +X → +π/2, −X → −π/2. Kept next to `surfaceQuatFromNormal`
+// so the two stay in lockstep — the formula is only valid for its basis.
+export function getDownSlopeYaw(lx: number, lz: number, seg: RoofSegmentNode): number {
+  const n = getAnalyticalNormal(lx, lz, seg)
+  if (n.x === 0 && n.z === 0) return 0
+  return Math.atan2(n.x * n.y, n.z)
+}
diff --git a/packages/nodes/src/shared/roof-wall-opening-cut.ts b/packages/nodes/src/shared/roof-wall-opening-cut.ts
index 41f189bf..d8af5cb9 100644
--- a/packages/nodes/src/shared/roof-wall-opening-cut.ts
+++ b/packages/nodes/src/shared/roof-wall-opening-cut.ts
@@ -1,26 +1,22 @@
-import type { RoofSegmentNode, RoofWallFaceId } from '@pascal-app/core'
+import type { DoorNode, RoofSegmentNode, WindowNode } from '@pascal-app/core'
 import { getRoofWallFaceFrame, roofFacePointToSegment } from '@pascal-app/core'
+import { buildOpeningCutoutGeometry, hasFlatOpeningCutoutBottom } from '@pascal-app/viewer'
 import * as THREE from 'three'
 
-type RoofWallOpening = {
-  roofSegmentId?: string
-  roofFace?: RoofWallFaceId
-  position: [number, number, number]
-  width: number
-  height: number
-}
-
 /**
  * CSG cut for a door / window hosted on a roof-segment wall face
- * (`capabilities.roofAccessory.buildCut`). A box through the wall
+ * (`capabilities.roofAccessory.buildCut`). The cut goes through the wall
  * mid-plane, derived from the CURRENT host geometry (the opening stores
  * face-local coords), so the hole follows segment resizes for free.
+ * Plain rectangles cut a box; shaped openings (arch / rounded /
+ * frameless `opening` kind) reuse the wall pipeline's cutout profile so
+ * roof-hosted holes match wall-hosted ones.
  *
  * Returns null for wall-hosted openings: their cut is handled by the
  * wall system's own cutout pipeline.
  */
 export function buildRoofWallOpeningCut(
-  node: RoofWallOpening,
+  node: DoorNode | WindowNode,
   hostSegment: RoofSegmentNode,
 ): THREE.BufferGeometry | null {
   if (!node.roofSegmentId || !node.roofFace) return null
@@ -32,8 +28,10 @@ export function buildRoofWallOpeningCut(
 
   // A door's cut bottom is coplanar with the wall brush base — extend it
   // slightly downward so three-bvh-csg never has to clip coplanar faces.
+  // Only a flat bottom chord may extend; a rounded bottom is never
+  // coplanar and shifting it would distort the profile.
   const bottom = node.position[1] - node.height / 2
-  const bottomPad = bottom < 0.005 ? 0.02 : 0
+  const bottomPad = bottom < 0.005 && hasFlatOpeningCutoutBottom(node) ? 0.02 : 0
 
   const center = roofFacePointToSegment(hostSegment, node.roofFace, [
     node.position[0],
@@ -42,9 +40,35 @@ export function buildRoofWallOpeningCut(
   ])
   const { yaw } = getRoofWallFaceFrame(hostSegment, node.roofFace)
 
-  const geo = new THREE.BoxGeometry(node.width, node.height + bottomPad, depth)
-  geo.translate(0, -bottomPad / 2, 0)
+  const geo = buildCutGeometry(node, wallThickness, depth, bottomPad)
   geo.rotateY(yaw)
   geo.translate(center[0], center[1], center[2])
   return geo
 }
+
+function buildCutGeometry(
+  node: DoorNode | WindowNode,
+  wallThickness: number,
+  depth: number,
+  bottomPad: number,
+): THREE.BufferGeometry {
+  const shaped =
+    node.openingKind === 'opening' ||
+    node.openingShape === 'arch' ||
+    node.openingShape === 'rounded'
+
+  if (!shaped) {
+    const geo = new THREE.BoxGeometry(node.width, node.height + bottomPad, depth)
+    geo.translate(0, -bottomPad / 2, 0)
+    return geo
+  }
+
+  const halfWidth = node.width / 2
+  const halfHeight = node.height / 2
+  return buildOpeningCutoutGeometry(
+    node,
+    { left: -halfWidth, right: halfWidth, bottom: -halfHeight - bottomPad, top: halfHeight },
+    depth,
+    wallThickness,
+  )
+}
diff --git a/packages/nodes/src/shared/wall-opening-alignment.ts b/packages/nodes/src/shared/wall-opening-alignment.ts
index 43af9e46..48f8cc30 100644
--- a/packages/nodes/src/shared/wall-opening-alignment.ts
+++ b/packages/nodes/src/shared/wall-opening-alignment.ts
@@ -21,7 +21,8 @@ const MIN_AXIS_COMPONENT = 0.5
  * runs along and map it to the along-wall coordinate that lands the opening on
  * it. Falls back to the half-metre snap when nothing aligns, and clears the
  * guide on bypass / no-match. Returns the localX to use (X-clamped to the wall
- * given `width`). `bypass` (Alt) disables alignment.
+ * given `width`). `bypass` disables alignment; `bypassSnap` also skips the
+ * half-metre fallback.
  */
 export function resolveWallSlideAlignment(args: {
   wallNode: WallNode
@@ -29,9 +30,10 @@ export function resolveWallSlideAlignment(args: {
   width: number
   candidates: readonly AlignmentAnchor[]
   bypass: boolean
+  bypassSnap?: boolean
 }): number {
-  const { wallNode, rawLocalX, width, candidates, bypass } = args
-  const base = snapToHalf(rawLocalX)
+  const { wallNode, rawLocalX, width, candidates, bypass, bypassSnap = false } = args
+  const base = bypassSnap ? rawLocalX : snapToHalf(rawLocalX)
   if (bypass || candidates.length === 0) {
     useAlignmentGuides.getState().clear()
     return base
diff --git a/packages/nodes/src/shelf/floorplan-move.ts b/packages/nodes/src/shelf/floorplan-move.ts
index 9b5dbe75..c72eabfd 100644
--- a/packages/nodes/src/shelf/floorplan-move.ts
+++ b/packages/nodes/src/shelf/floorplan-move.ts
@@ -66,7 +66,7 @@ export const shelfFloorplanMoveTarget: FloorplanMoveTarget<ShelfNode> = ({ node,
       const gridSnapped = resolveCursor(planPoint, { snap }) as WallPlanPoint
       // Figma-style alignment layered on the grid snap — the shelf footprint
       // edges snap to neighbours / wall faces and a guide is published. Alt
-      // bypasses (matches placement tools' "No snap").
+      // bypasses alignment; Shift bypasses all snap.
       const { point: snapped } = applyFloorplanAlignment(
         gridSnapped,
         movingFootprintAnchors(
@@ -76,7 +76,7 @@ export const shelfFloorplanMoveTarget: FloorplanMoveTarget<ShelfNode> = ({ node,
           originalRotationY,
         ),
         candidates,
-        { bypass: modifiers.altKey },
+        { bypass: modifiers.altKey || modifiers.shiftKey },
       )
       const next: [number, number, number] = [snapped[0], originalPosition[1], snapped[1]]
       lastPosition = next
@@ -85,7 +85,7 @@ export const shelfFloorplanMoveTarget: FloorplanMoveTarget<ShelfNode> = ({ node,
       // and the placement coordinators. Item / slab / wall flows fire
       // the same cue, so the shelf following along is the expected UX.
       const snapKey = `${snapped[0]},${snapped[1]}`
-      if (snapKey !== lastSnapKey) {
+      if (!modifiers.shiftKey && snapKey !== lastSnapKey) {
         triggerSFX('sfx:grid-snap')
         lastSnapKey = snapKey
       }
diff --git a/packages/nodes/src/shelf/tool.tsx b/packages/nodes/src/shelf/tool.tsx
index 4dbc866b..585de70f 100644
--- a/packages/nodes/src/shelf/tool.tsx
+++ b/packages/nodes/src/shelf/tool.tsx
@@ -83,7 +83,8 @@ const ShelfTool = () => {
         rawZ: event.localPosition[2],
         gridStep: useEditor.getState().gridSnapStep,
         candidates: alignmentCandidates,
-        bypassAlignment: event.nativeEvent?.altKey === true,
+        bypassAlignment: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassGrid: event.nativeEvent?.shiftKey === true,
       })
       useAlignmentGuides.getState().set(guides)
 
@@ -97,7 +98,10 @@ const ShelfTool = () => {
       lastCursorRef.current = position
 
       const prev = previousSnapRef.current
-      if (!prev || prev[0] !== position[0] || prev[1] !== position[2]) {
+      if (
+        event.nativeEvent?.shiftKey !== true &&
+        (!prev || prev[0] !== position[0] || prev[1] !== position[2])
+      ) {
         triggerSFX('sfx:grid-snap')
         previousSnapRef.current = [position[0], position[2]]
       }
@@ -110,7 +114,12 @@ const ShelfTool = () => {
       // first). Both paths apply the same grid snap.
       const position =
         lastCursorRef.current ??
-        getLevelLocalSnappedPosition(activeLevelId, event, useEditor.getState().gridSnapStep)
+        getLevelLocalSnappedPosition(
+          activeLevelId,
+          event,
+          useEditor.getState().gridSnapStep,
+          event.nativeEvent?.shiftKey === true,
+        )
       const shelf = ShelfNode.parse({
         ...shelfDefinition.defaults(),
         name: 'Shelf',
diff --git a/packages/nodes/src/skylight/frame-csg.ts b/packages/nodes/src/skylight/frame-csg.ts
index 1dcbd819..da82d81e 100644
--- a/packages/nodes/src/skylight/frame-csg.ts
+++ b/packages/nodes/src/skylight/frame-csg.ts
@@ -67,14 +67,5 @@ export function buildFrameGeometry({
 
   frameGeo.translate(0, -totalDepth / 2 + curbH, 0)
 
-  // WebGPU node renderer requests `uv2` on every geometry for lightmap support.
-  // CSG output only carries position + normal + uv. Copy uv → uv2 so the
-  // AttributeNode lookup doesn't fail and invalidate the render pipeline.
-  // Mirrors `ensureUv2Attribute` in packages/viewer/src/systems/roof/roof-system.tsx.
-  const uv = frameGeo.getAttribute('uv')
-  if (uv) {
-    frameGeo.setAttribute('uv2', new THREE.Float32BufferAttribute(Array.from(uv.array), 2))
-  }
-
   return frameGeo
 }
diff --git a/packages/nodes/src/skylight/move-tool.tsx b/packages/nodes/src/skylight/move-tool.tsx
index b93bfc4c..2255ec08 100644
--- a/packages/nodes/src/skylight/move-tool.tsx
+++ b/packages/nodes/src/skylight/move-tool.tsx
@@ -98,7 +98,7 @@ export default function MoveSkylightTool({ node }: { node: SkylightNode }) {
     const onRoofMove = (event: RoofEvent) => {
       const sx = Math.round(event.position[0] * 20) / 20
       const sz = Math.round(event.position[2] * 20) / 20
-      if (sx !== lastSnapX || sz !== lastSnapZ) {
+      if (event.nativeEvent?.shiftKey !== true && (sx !== lastSnapX || sz !== lastSnapZ)) {
         triggerSFX('sfx:grid-snap')
         lastSnapX = sx
         lastSnapZ = sz
diff --git a/packages/nodes/src/skylight/renderer.tsx b/packages/nodes/src/skylight/renderer.tsx
index 47bc6dd5..4111cd77 100644
--- a/packages/nodes/src/skylight/renderer.tsx
+++ b/packages/nodes/src/skylight/renderer.tsx
@@ -628,8 +628,7 @@ const SkylightRenderer = ({ node: storeNode }: { node: SkylightNode }) => {
 
   const glassMaterial = useMemo(() => {
     // Untextured glass (and textures-off mode) takes the themed 'glazing'
-    // role material — already DoubleSide + semi-transparent, and shared
-    // from the cache, so it must not be mutated.
+    // role material from the shared cache, so it must not be mutated.
     if (!textures || (!node.glassMaterial && !node.glassMaterialPreset)) {
       return createSurfaceRoleMaterial('glazing', colorPreset, undefined, sceneTheme)
     }
@@ -638,7 +637,6 @@ const SkylightRenderer = ({ node: storeNode }: { node: SkylightNode }) => {
       : (createMaterialFromPresetRef(node.glassMaterialPreset, shading) ??
         defaultGlassMaterial.clone())
     if (mat && typeof mat === 'object') {
-      ;(mat as THREE.Material).side = THREE.DoubleSide
       if (mat instanceof THREE.MeshPhysicalMaterial) {
         mat.thickness = glassThickness
       }
diff --git a/packages/nodes/src/skylight/tool.tsx b/packages/nodes/src/skylight/tool.tsx
index cbaadcb4..ffc442c8 100644
--- a/packages/nodes/src/skylight/tool.tsx
+++ b/packages/nodes/src/skylight/tool.tsx
@@ -59,7 +59,7 @@ const SkylightTool = () => {
       const sx = Math.round(wx * 20) / 20
       const sz = Math.round(wz * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
diff --git a/packages/nodes/src/slab/boundary-editor.tsx b/packages/nodes/src/slab/boundary-editor.tsx
index dde74c82..43726dd3 100644
--- a/packages/nodes/src/slab/boundary-editor.tsx
+++ b/packages/nodes/src/slab/boundary-editor.tsx
@@ -73,6 +73,7 @@ export const SlabBoundaryEditor: React.FC<{ slabId: SlabNode['id'] }> = ({ slabI
         levelId: slabLevelId,
         excludeId: slabId,
         altKey: context.nativeEvent?.altKey === true,
+        shiftKey: context.nativeEvent?.shiftKey === true,
       }).point,
     [slabId, slabLevelId],
   )
diff --git a/packages/nodes/src/slab/definition.ts b/packages/nodes/src/slab/definition.ts
index 01d0b971..ecb2ff65 100644
--- a/packages/nodes/src/slab/definition.ts
+++ b/packages/nodes/src/slab/definition.ts
@@ -166,7 +166,7 @@ export const slabDefinition: NodeDefinition<typeof SlabNode> = {
   handles: slabHandles,
 
   // Stage D: kind-owned placement tool. Multi-click polygon drawing
-  // with axis/45° snap (Shift to defeat).
+  // with 15° angle snap (Shift to defeat).
   tool: () => import('./tool'),
 
   // Stage D — all four slab drag-affordances live in this folder.
diff --git a/packages/nodes/src/slab/floorplan-affordances.ts b/packages/nodes/src/slab/floorplan-affordances.ts
index b7554530..dfedcf5c 100644
--- a/packages/nodes/src/slab/floorplan-affordances.ts
+++ b/packages/nodes/src/slab/floorplan-affordances.ts
@@ -37,6 +37,7 @@ const slabSnapOptions = {
       excludeId: node.id,
       nodes: sceneNodes,
       altKey: modifiers.altKey,
+      shiftKey: modifiers.shiftKey,
     }).point
   },
 }
diff --git a/packages/nodes/src/slab/move-tool.tsx b/packages/nodes/src/slab/move-tool.tsx
index 19b36c24..df684b54 100644
--- a/packages/nodes/src/slab/move-tool.tsx
+++ b/packages/nodes/src/slab/move-tool.tsx
@@ -167,14 +167,17 @@ export const MoveSlabTool: React.FC<{ node: SlabNode }> = ({ node }) => {
     const onGridMove = (event: GridEvent) => {
       if (isFloorplanSourcedEvent(event)) return
       const gridStep = getSegmentGridStep()
+      const bypassSnap = event.nativeEvent?.shiftKey === true
       const [localX, localZ] = snapFenceDraftPoint({
         point: [event.localPosition[0], event.localPosition[2]],
         walls: levelWalls,
         fences: levelFences,
+        bypassSnap,
         gridSnap: (p) => snapBuildingLocalToWorldGrid(p, gridStep),
       })
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (localX !== previousGridPosRef.current[0] || localZ !== previousGridPosRef.current[1])
       ) {
@@ -190,8 +193,8 @@ export const MoveSlabTool: React.FC<{ node: SlabNode }> = ({ node }) => {
 
       // Figma-style alignment snap: align the slab's translated polygon
       // vertices to other objects' anchors; fold the snap into the delta and
-      // publish a guide. Alt bypasses.
-      const bypass = event.nativeEvent?.altKey === true
+      // publish a guide. Alt bypasses alignment; Shift bypasses all snap.
+      const bypass = event.nativeEvent?.altKey === true || bypassSnap
       if (!bypass && alignmentCandidates.length > 0) {
         const result = resolveAlignmentForActiveBuilding({
           moving: polygonAnchors(slabId, translatePolygon(originalPolygon, deltaX, deltaZ)),
diff --git a/packages/nodes/src/slab/tool.tsx b/packages/nodes/src/slab/tool.tsx
index 1f734cab..57c95298 100644
--- a/packages/nodes/src/slab/tool.tsx
+++ b/packages/nodes/src/slab/tool.tsx
@@ -1,6 +1,13 @@
 'use client'
 
-import { emitter, type GridEvent, type LevelNode, useScene } from '@pascal-app/core'
+import {
+  DEFAULT_ANGLE_STEP,
+  emitter,
+  type GridEvent,
+  type LevelNode,
+  snapPointAlongAngleRay,
+  useScene,
+} from '@pascal-app/core'
 import {
   CursorSphere,
   clearSlabSnapFeedback,
@@ -20,7 +27,7 @@ import { SlabNode } from './schema'
  *
  * Multi-click polygon drawing: each click adds a vertex; clicking near
  * the first vertex (or double-clicking) closes the polygon and creates
- * the slab. Shift-modifier defeats the axis/45° snap during drag.
+ * the slab. Shift-modifier defeats the 15° angle snap during drag.
  *
  * Not a `DragAction` — same reasoning as `tool.tsx` for fence: this is
  * a stateful sequence of grid:click events with preview state, not a
@@ -29,28 +36,6 @@ import { SlabNode } from './schema'
 
 const Y_OFFSET = 0.02
 
-function calculateSnapPoint(
-  lastPoint: [number, number],
-  currentPoint: [number, number],
-): [number, number] {
-  const [x1, y1] = lastPoint
-  const [x, y] = currentPoint
-  const dx = x - x1
-  const dy = y - y1
-  const absDx = Math.abs(dx)
-  const absDy = Math.abs(dy)
-  const horizontalDist = absDy
-  const verticalDist = absDx
-  const diagonalDist = Math.abs(absDx - absDy)
-  const minDist = Math.min(horizontalDist, verticalDist, diagonalDist)
-  if (minDist === diagonalDist) {
-    const diagonalLength = Math.min(absDx, absDy)
-    return [x1 + Math.sign(dx) * diagonalLength, y1 + Math.sign(dy) * diagonalLength]
-  }
-  if (minDist === horizontalDist) return [x, y1]
-  return [x1, y]
-}
-
 function commitSlabDrawing(levelId: LevelNode['id'], points: Array<[number, number]>): string {
   const { createNode, nodes } = useScene.getState()
   const slabCount = Object.values(nodes).filter((n) => n.type === 'slab').length
@@ -90,24 +75,36 @@ export const SlabTool: React.FC = () => {
     const onGridMove = (event: GridEvent) => {
       if (!cursorRef.current) return
       const rawPoint: [number, number] = [event.localPosition[0], event.localPosition[2]]
+      const bypassSnap = shiftPressed.current || event.nativeEvent?.shiftKey === true
       const gridX = Math.round(rawPoint[0] * 2) / 2
       const gridZ = Math.round(rawPoint[1] * 2) / 2
-      const gridPosition: [number, number] = [gridX, gridZ]
+      const gridPosition: [number, number] = bypassSnap ? rawPoint : [gridX, gridZ]
       setCursorPosition(gridPosition)
       setLevelY(event.localPosition[1])
       const lastPoint = points[points.length - 1]
-      const orthoPoint =
-        shiftPressed.current || !lastPoint
+      // 15° angle snap from the raw cursor (matching the 2D floorplan
+      // pipeline) with the distance snapped along the ray to the grid step.
+      const orthoPoint: [number, number] =
+        bypassSnap || !lastPoint
           ? gridPosition
-          : calculateSnapPoint(lastPoint, gridPosition)
+          : [
+              ...snapPointAlongAngleRay(
+                lastPoint,
+                rawPoint,
+                DEFAULT_ANGLE_STEP,
+                useEditor.getState().gridSnapStep,
+              ),
+            ]
       const displayPoint = resolveSlabPlanPointSnap({
         rawPoint,
         fallbackPoint: orthoPoint,
         levelId: currentLevelId,
         altKey: event.nativeEvent?.altKey === true,
+        shiftKey: bypassSnap,
       }).point
       setSnappedCursorPosition(displayPoint)
       if (
+        !bypassSnap &&
         points.length > 0 &&
         previousSnappedPointRef.current &&
         (displayPoint[0] !== previousSnappedPointRef.current[0] ||
@@ -163,8 +160,12 @@ export const SlabTool: React.FC = () => {
     const onKeyUp = (e: KeyboardEvent) => {
       if (e.key === 'Shift') shiftPressed.current = false
     }
+    const onWindowBlur = () => {
+      shiftPressed.current = false
+    }
     document.addEventListener('keydown', onKeyDown)
     document.addEventListener('keyup', onKeyUp)
+    window.addEventListener('blur', onWindowBlur)
 
     emitter.on('grid:move', onGridMove)
     emitter.on('grid:click', onGridClick)
@@ -174,6 +175,7 @@ export const SlabTool: React.FC = () => {
     return () => {
       document.removeEventListener('keydown', onKeyDown)
       document.removeEventListener('keyup', onKeyUp)
+      window.removeEventListener('blur', onWindowBlur)
       emitter.off('grid:move', onGridMove)
       emitter.off('grid:click', onGridClick)
       emitter.off('grid:double-click', onGridDoubleClick)
diff --git a/packages/nodes/src/solar-panel/move-tool.tsx b/packages/nodes/src/solar-panel/move-tool.tsx
index c17973c7..402a525e 100644
--- a/packages/nodes/src/solar-panel/move-tool.tsx
+++ b/packages/nodes/src/solar-panel/move-tool.tsx
@@ -100,7 +100,7 @@ export default function MoveSolarPanelTool({ node }: { node: SolarPanelNode }) {
 
       const sx = Math.round(target.localX * 20) / 20
       const sz = Math.round(target.localZ * 20) / 20
-      if (sx !== lastSnapX || sz !== lastSnapZ) {
+      if (event.nativeEvent?.shiftKey !== true && (sx !== lastSnapX || sz !== lastSnapZ)) {
         triggerSFX('sfx:grid-snap')
         lastSnapX = sx
         lastSnapZ = sz
diff --git a/packages/nodes/src/solar-panel/tool.tsx b/packages/nodes/src/solar-panel/tool.tsx
index 9289e230..1fd468cc 100644
--- a/packages/nodes/src/solar-panel/tool.tsx
+++ b/packages/nodes/src/solar-panel/tool.tsx
@@ -72,7 +72,7 @@ const SolarPanelTool = () => {
       const sx = Math.round(wx * 20) / 20
       const sz = Math.round(wz * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
diff --git a/packages/nodes/src/spawn/tool.tsx b/packages/nodes/src/spawn/tool.tsx
index fc7b7c8e..69f4475b 100644
--- a/packages/nodes/src/spawn/tool.tsx
+++ b/packages/nodes/src/spawn/tool.tsx
@@ -22,15 +22,23 @@ function getExistingSpawnIds() {
     .sort()
 }
 
-function getLevelLocalPosition(levelId: string, event: GridEvent): [number, number, number] {
+function getLevelLocalPosition(
+  levelId: string,
+  event: GridEvent,
+  bypassSnap: boolean,
+): [number, number, number] {
   const levelObject = sceneRegistry.nodes.get(levelId)
   if (!levelObject) {
-    return [roundToHalf(event.localPosition[0]), 0, roundToHalf(event.localPosition[2])]
+    return bypassSnap
+      ? [event.localPosition[0], 0, event.localPosition[2]]
+      : [roundToHalf(event.localPosition[0]), 0, roundToHalf(event.localPosition[2])]
   }
   worldVector.set(event.position[0], event.position[1], event.position[2])
   levelObject.updateWorldMatrix(true, false)
   levelObject.worldToLocal(worldVector)
-  return [roundToHalf(worldVector.x), 0, roundToHalf(worldVector.z)]
+  return bypassSnap
+    ? [worldVector.x, 0, worldVector.z]
+    : [roundToHalf(worldVector.x), 0, roundToHalf(worldVector.z)]
 }
 
 /**
@@ -52,8 +60,9 @@ const SpawnTool = () => {
       // Cursor lives in the ToolManager's building-local group. Use
       // event.localPosition directly (already building-local) with the
       // same half-meter snap the legacy tool uses.
-      const nextX = roundToHalf(event.localPosition[0])
-      const nextZ = roundToHalf(event.localPosition[2])
+      const bypassSnap = event.nativeEvent?.shiftKey === true
+      const nextX = bypassSnap ? event.localPosition[0] : roundToHalf(event.localPosition[0])
+      const nextZ = bypassSnap ? event.localPosition[2] : roundToHalf(event.localPosition[2])
       const position: [number, number, number] = [nextX, 0, nextZ]
       const previewNode = SpawnNode.parse({
         name: 'Spawn Point',
@@ -72,14 +81,14 @@ const SpawnTool = () => {
       // not every frame the mouse moves within the same cell. Matches the
       // wall / slab / curve tools.
       const prev = previousSnapRef.current
-      if (!prev || prev[0] !== nextX || prev[1] !== nextZ) {
+      if (!bypassSnap && (!prev || prev[0] !== nextX || prev[1] !== nextZ)) {
         triggerSFX('sfx:grid-snap')
         previousSnapRef.current = [nextX, nextZ]
       }
     }
 
     const onGridClick = (event: GridEvent) => {
-      const next = getLevelLocalPosition(activeLevelId, event)
+      const next = getLevelLocalPosition(activeLevelId, event, event.nativeEvent?.shiftKey === true)
       const [existingSpawnId, ...duplicates] = getExistingSpawnIds()
       let placedId: SpawnNode['id']
 
diff --git a/packages/nodes/src/stair/floorplan-move.ts b/packages/nodes/src/stair/floorplan-move.ts
index e7b13a4d..1b86fc96 100644
--- a/packages/nodes/src/stair/floorplan-move.ts
+++ b/packages/nodes/src/stair/floorplan-move.ts
@@ -43,7 +43,7 @@ export const stairFloorplanMoveTarget: FloorplanMoveTarget<StairNode> = ({ node,
       const step = getSegmentGridStep()
       const snap = (value: number) => (modifiers.shiftKey ? value : snapScalar(value, step))
       const [gx, gz] = resolveCursor(planPoint, { snap })
-      // Figma alignment on the actual stair footprint (Alt bypasses),
+      // Figma alignment on the actual stair footprint (Alt bypasses alignment; Shift all snap),
       // matching the 3D move tool. Publishes guides via `useAlignmentGuides`.
       const movingAnchors = movingAlignmentAnchors(node, nodes, gx, gz, node.rotation ?? 0)
       const { point: aligned } = applyFloorplanAlignment(
@@ -52,7 +52,7 @@ export const stairFloorplanMoveTarget: FloorplanMoveTarget<StairNode> = ({ node,
           ? movingAnchors
           : [{ nodeId: node.id, kind: 'corner', x: gx, z: gz }],
         candidates,
-        { bypass: modifiers.altKey },
+        { bypass: modifiers.altKey || modifiers.shiftKey },
       )
       const sx = aligned[0]
       const sz = aligned[1]
diff --git a/packages/nodes/src/turbine-vent/move-tool.tsx b/packages/nodes/src/turbine-vent/move-tool.tsx
index 3f45e9bb..d0f159d9 100644
--- a/packages/nodes/src/turbine-vent/move-tool.tsx
+++ b/packages/nodes/src/turbine-vent/move-tool.tsx
@@ -67,7 +67,10 @@ export default function MoveTurbineVentTool({ node }: { node: TurbineVentNode })
 
       const sx = Math.round(target.localX * 20) / 20
       const sz = Math.round(target.localZ * 20) / 20
-      if (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz) {
+      if (
+        event.nativeEvent?.shiftKey !== true &&
+        (!lastSnap || lastSnap[0] !== sx || lastSnap[1] !== sz)
+      ) {
         triggerSFX('sfx:grid-snap')
         lastSnap = [sx, sz]
       }
diff --git a/packages/nodes/src/turbine-vent/tool.tsx b/packages/nodes/src/turbine-vent/tool.tsx
index 5c88bb93..4a7c2bd2 100644
--- a/packages/nodes/src/turbine-vent/tool.tsx
+++ b/packages/nodes/src/turbine-vent/tool.tsx
@@ -14,7 +14,7 @@ import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useMemo, useRef, useState } from 'react'
 import * as THREE from 'three'
 import { resolveRoofSegmentHit } from '../shared/roof-segment-hit'
-import { getAnalyticalNormal, surfaceQuatFromNormal } from '../shared/roof-surface'
+import { getAnalyticalNormal, getDownSlopeYaw, surfaceQuatFromNormal } from '../shared/roof-surface'
 import { turbineVentDefinition } from './definition'
 import TurbineVentPreview from './preview'
 
@@ -33,6 +33,7 @@ const TurbineVentTool = () => {
   const [previewPos, setPreviewPos] = useState<[number, number, number] | null>(null)
   const [previewSurfaceQuat, setPreviewSurfaceQuat] = useState<THREE.Quaternion | null>(null)
   const [previewYaw, setPreviewYaw] = useState(0)
+  const [previewRotation, setPreviewRotation] = useState(0)
   const lastSnapRef = useRef<[number, number] | null>(null)
 
   const previewNode = useMemo(
@@ -41,9 +42,9 @@ const TurbineVentTool = () => {
         ...turbineVentDefinition.defaults(),
         name: 'Turbine Vent',
         position: [0, 0, 0],
-        rotation: 0,
+        rotation: previewRotation,
       }),
-    [],
+    [previewRotation],
   )
 
   useEffect(() => {
@@ -65,7 +66,7 @@ const TurbineVentTool = () => {
       const sx = Math.round(wx * 20) / 20
       const sz = Math.round(wz * 20) / 20
       const prev = lastSnapRef.current
-      if (!prev || prev[0] !== sx || prev[1] !== sz) {
+      if (event.nativeEvent?.shiftKey !== true && (!prev || prev[0] !== sx || prev[1] !== sz)) {
         triggerSFX('sfx:grid-snap')
         lastSnapRef.current = [sx, sz]
       }
@@ -76,6 +77,7 @@ const TurbineVentTool = () => {
       const normal = getAnalyticalNormal(hit.localX, hit.localZ, hit.segment)
       setPreviewSurfaceQuat(surfaceQuatFromNormal(normal, new THREE.Quaternion()))
       setPreviewYaw((event.node.rotation ?? 0) + (hit.segment.rotation ?? 0))
+      setPreviewRotation(getDownSlopeYaw(hit.localX, hit.localZ, hit.segment))
       setPreviewPos(worldToBuildingLocal(wx, wy, wz))
       event.stopPropagation()
     }
@@ -95,7 +97,7 @@ const TurbineVentTool = () => {
         name: 'Turbine Vent',
         roofSegmentId: hit.segment.id,
         position: [hit.localX, hit.localY, hit.localZ],
-        rotation: 0,
+        rotation: getDownSlopeYaw(hit.localX, hit.localZ, hit.segment),
       })
       state.createNode(vent, hit.segment.id as AnyNodeId)
       state.dirtyNodes.add(hit.segment.id as AnyNodeId)
diff --git a/packages/nodes/src/wall/curve-tool.tsx b/packages/nodes/src/wall/curve-tool.tsx
index 08bce22a..f1cd2e0c 100644
--- a/packages/nodes/src/wall/curve-tool.tsx
+++ b/packages/nodes/src/wall/curve-tool.tsx
@@ -85,11 +85,12 @@ export const CurveWallTool: React.FC<{ node: WallNode }> = ({ node }) => {
     }
 
     const onGridMove = (event: GridEvent) => {
+      const bypassSnap = shiftPressedRef.current || event.nativeEvent?.shiftKey === true
       const snapStep = getSegmentGridStep()
       // Snap the cursor on the WORLD XZ grid (still in building-local
       // coords for the rest of the math) so a rotated building doesn't
       // pull the curve handle off the visible grid lines.
-      const [snappedLocalX, snappedLocalZ] = shiftPressedRef.current
+      const [snappedLocalX, snappedLocalZ] = bypassSnap
         ? [event.localPosition[0], event.localPosition[2]]
         : snapBuildingLocalToWorldGrid([event.localPosition[0], event.localPosition[2]], snapStep)
       const localX = snappedLocalX
@@ -99,7 +100,7 @@ export const CurveWallTool: React.FC<{ node: WallNode }> = ({ node }) => {
         (localX - chord.midpoint.x) * chord.normal.x +
         (localZ - chord.midpoint.y) * chord.normal.y
       )
-      const snappedOffset = shiftPressedRef.current
+      const snappedOffset = bypassSnap
         ? offsetFromMidpoint
         : snapScalarToGrid(offsetFromMidpoint, snapStep)
       const nextCurveOffset = normalizeWallCurveOffset(
@@ -108,6 +109,7 @@ export const CurveWallTool: React.FC<{ node: WallNode }> = ({ node }) => {
       )
 
       if (
+        !bypassSnap &&
         previousCurveOffsetRef.current !== null &&
         nextCurveOffset !== previousCurveOffsetRef.current
       ) {
diff --git a/packages/nodes/src/wall/definition.ts b/packages/nodes/src/wall/definition.ts
index 2462a262..0e0face2 100644
--- a/packages/nodes/src/wall/definition.ts
+++ b/packages/nodes/src/wall/definition.ts
@@ -108,7 +108,7 @@ export const wallDefinition: NodeDefinition<typeof WallNode> = {
 
   toolHints: [
     { key: 'Left click', label: 'Set wall start / end' },
-    { key: 'Shift', label: 'Allow non-45° angles' },
+    { key: 'Shift', label: 'Free angle (no 15° snap)' },
     { key: 'Esc', label: 'Cancel' },
   ],
 
diff --git a/packages/nodes/src/wall/floorplan-affordances.ts b/packages/nodes/src/wall/floorplan-affordances.ts
index 85bad124..ced8ea75 100644
--- a/packages/nodes/src/wall/floorplan-affordances.ts
+++ b/packages/nodes/src/wall/floorplan-affordances.ts
@@ -18,7 +18,6 @@ import {
   snapScalarToGrid,
   snapWallDraftPoint,
   useAlignmentGuides,
-  WALL_FINE_GRID_STEP,
   WALL_GRID_STEP,
   type WallPlanPoint,
 } from '@pascal-app/editor'
@@ -187,23 +186,22 @@ export const wallMoveEndpointAffordance: FloorplanAffordance<WallNode> = {
         // the legacy flow.
         const sceneNodes = useScene.getState().nodes
         const walls = collectLevelWalls(sceneNodes, node.id)
-        // Endpoint move = grid snap, never 45° from the fixed corner —
-        // the angle snap is for initial draft only. Shift switches to
-        // the fine grid step for precision, matching the 3D
-        // `MoveWallEndpointTool`.
-        const worldStep = modifiers.shiftKey ? WALL_FINE_GRID_STEP : WALL_GRID_STEP
+        // Endpoint move = grid snap, never 45° from the fixed corner.
+        // Shift bypasses grid, magnetic, and alignment snap.
         const snapped = snapWallDraftPoint({
           point: planPoint as WallPlanPoint,
           walls,
           ignoreWallIds: [node.id],
-          step: modifiers.shiftKey ? WALL_FINE_GRID_STEP : undefined,
-          gridSnap: (p) => snapBuildingLocalToWorldGrid(p, worldStep),
+          bypassSnap: modifiers.shiftKey,
+          magnetic: !modifiers.shiftKey,
+          gridSnap: (p) => snapBuildingLocalToWorldGrid(p, WALL_GRID_STEP),
         })
         // Figma-style alignment on the dragged corner — snaps it onto another
         // object's edge / wall face and publishes a guide. The dragged wall
         // and its linked siblings (which cascade with the corner) are excluded
         // from the candidate pool. Alt is reserved for detach, NOT bypass.
         const aligned = alignFloorplanDraftPoint(snapped, {
+          bypass: modifiers.shiftKey,
           excludeIds: [node.id, ...linkedWalls.map((w) => w.id)],
         }) as WallPlanPoint
 
diff --git a/packages/nodes/src/wall/move-endpoint-tool.tsx b/packages/nodes/src/wall/move-endpoint-tool.tsx
index 2f5f56e0..02d3ec8c 100644
--- a/packages/nodes/src/wall/move-endpoint-tool.tsx
+++ b/packages/nodes/src/wall/move-endpoint-tool.tsx
@@ -28,7 +28,6 @@ import {
   useAlignmentGuides,
   useEditor,
   useWallSnapIndicator,
-  WALL_FINE_GRID_STEP,
   type WallPlanPoint,
 } from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
@@ -288,16 +287,15 @@ export const MoveWallEndpointTool: React.FC<{ target: MovingWallEndpoint }> = ({
       // drag by warping the endpoint onto the nearest 45° line from
       // the fixed corner.
       //
-      // Shift switches to the *fine* grid step (`WALL_FINE_GRID_STEP`)
-      // for precision placement, so it can land on positions the
-      // active grid would skip (e.g. 0.05m increments when the active
-      // grid is 0.5m). It does NOT bypass snap.
+      // Shift is a hard snap bypass: raw endpoint position, no grid,
+      // no magnetic wall snap, and no alignment guide snap.
+      const bypassSnap = shiftPressedRef.current || event.nativeEvent.shiftKey
       const snapResult = snapWallDraftPointDetailed({
         point: planPoint,
         walls: levelWalls,
         ignoreWallIds: [nodeId],
-        step: shiftPressedRef.current ? WALL_FINE_GRID_STEP : undefined,
-        magnetic: useEditor.getState().magneticSnap,
+        bypassSnap,
+        magnetic: !bypassSnap && useEditor.getState().magneticSnap,
       })
       const snappedPoint = snapResult.point
 
@@ -308,7 +306,7 @@ export const MoveWallEndpointTool: React.FC<{ target: MovingWallEndpoint }> = ({
       // midpoint), never an empty-space bbox corner. Layered on top of the
       // grid + corner snap above; Alt is reserved for corner-detach here.
       let alignedPoint = snappedPoint
-      if (wallAlignmentCandidates.length > 0) {
+      if (!bypassSnap && wallAlignmentCandidates.length > 0) {
         const ar = resolveAlignment({
           moving: [{ nodeId, kind: 'corner', x: snappedPoint[0], z: snappedPoint[1] }],
           candidates: wallAlignmentCandidates,
@@ -318,9 +316,12 @@ export const MoveWallEndpointTool: React.FC<{ target: MovingWallEndpoint }> = ({
           alignedPoint = [snappedPoint[0] + ar.snap.dx, snappedPoint[1] + ar.snap.dz]
         }
         useAlignmentGuides.getState().set(ar.guides)
+      } else {
+        useAlignmentGuides.getState().clear()
       }
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (alignedPoint[0] !== previousGridPosRef.current[0] ||
           alignedPoint[1] !== previousGridPosRef.current[1])
diff --git a/packages/nodes/src/wall/move-tool.tsx b/packages/nodes/src/wall/move-tool.tsx
index 9e4b700f..1b327558 100644
--- a/packages/nodes/src/wall/move-tool.tsx
+++ b/packages/nodes/src/wall/move-tool.tsx
@@ -437,6 +437,7 @@ export const MoveWallTool: React.FC<{ node: WallNode }> = ({ node }) => {
     }
 
     const onGridMove = (event: GridEvent) => {
+      const bypassSnap = shiftPressedRef.current || event.nativeEvent?.shiftKey === true
       const rawX = event.localPosition[0]
       const rawZ = event.localPosition[2]
       const snapStep = getSegmentGridStep()
@@ -467,11 +468,11 @@ export const MoveWallTool: React.FC<{ node: WallNode }> = ({ node }) => {
       if (axis) {
         const originalProj = originalCenter[0] * axis[0] + originalCenter[1] * axis[1]
         const rawProj = originalProj + rawDeltaX * axis[0] + rawDeltaZ * axis[1]
-        const snappedProj = shiftPressedRef.current ? rawProj : snapScalarToGrid(rawProj, snapStep)
+        const snappedProj = bypassSnap ? rawProj : snapScalarToGrid(rawProj, snapStep)
         const perpDelta = snappedProj - originalProj
         deltaX = axis[0] * perpDelta
         deltaZ = axis[1] * perpDelta
-      } else if (shiftPressedRef.current) {
+      } else if (bypassSnap) {
         deltaX = rawDeltaX
         deltaZ = rawDeltaZ
       } else {
@@ -491,6 +492,7 @@ export const MoveWallTool: React.FC<{ node: WallNode }> = ({ node }) => {
       const constrainedGridPos: [number, number] = [anchor[0] + deltaX, anchor[1] + deltaZ]
 
       if (
+        !bypassSnap &&
         previousGridPosRef.current &&
         (constrainedGridPos[0] !== previousGridPosRef.current[0] ||
           constrainedGridPos[1] !== previousGridPosRef.current[1])
diff --git a/packages/nodes/src/wall/tool.tsx b/packages/nodes/src/wall/tool.tsx
index 8d1b0b97..25b02bda 100644
--- a/packages/nodes/src/wall/tool.tsx
+++ b/packages/nodes/src/wall/tool.tsx
@@ -26,8 +26,8 @@ import {
   triggerSFX,
   useAlignmentGuides,
   useEditor,
+  useSegmentDraftChain,
   useWallSnapIndicator,
-  WALL_FINE_GRID_STEP,
   type WallPlanPoint,
 } from '@pascal-app/editor'
 import { getSceneTheme, useViewer } from '@pascal-app/viewer'
@@ -532,6 +532,7 @@ export const WallTool: React.FC = () => {
       setAxisGuide(null)
       useAlignmentGuides.getState().clear()
       useWallSnapIndicator.getState().clear()
+      useSegmentDraftChain.getState().clear('wall')
     }
 
     const onGridMove = (event: GridEvent) => {
@@ -539,20 +540,21 @@ export const WallTool: React.FC = () => {
 
       const walls = getCurrentLevelWalls()
       const localPoint: WallPlanPoint = [event.localPosition[0], event.localPosition[2]]
-      // Default to the active grid step; Shift switches to the fine
-      // step (0.05m) for precision. No 45° angle snap — we want the
-      // cursor to track grid lines in every direction. Orthogonal
-      // walls fall out of grid snap naturally when the start sits on
-      // a grid intersection.
-      const step = shiftPressed.current ? WALL_FINE_GRID_STEP : undefined
-      const bypassAlign = event.nativeEvent?.altKey === true
+      // Default path: grid + magnetic snap, with 15° angle lock while
+      // drafting. Shift is a hard snap bypass: no grid, magnetic, angle,
+      // or alignment snap.
+      const bypassSnap = shiftPressed.current || event.nativeEvent?.shiftKey === true
+      const angleLocked = buildingState.current === 1 && !bypassSnap
+      const bypassAlign = event.nativeEvent?.altKey === true || bypassSnap
       const snapResult = snapWallDraftPointDetailed({
         point: localPoint,
         walls,
-        step,
-        magnetic: useEditor.getState().magneticSnap,
+        start: angleLocked ? [startingPoint.current.x, startingPoint.current.z] : undefined,
+        angleSnap: angleLocked,
+        bypassSnap,
+        magnetic: !bypassSnap && useEditor.getState().magneticSnap,
       })
-      gridPosition = alignPoint(snapResult.point, bypassAlign)
+      gridPosition = alignPoint(snapResult.point, bypassAlign || angleLocked)
       // Stand the magnetic beacon at the endpoint when it locked onto an
       // existing wall corner / wall point; clear it for plain grid/angle moves.
       useWallSnapIndicator
@@ -579,6 +581,7 @@ export const WallTool: React.FC = () => {
 
         const currentWallEnd: [number, number] = [snappedLocal[0], snappedLocal[1]]
         if (
+          !bypassSnap &&
           previousWallEnd &&
           (currentWallEnd[0] !== previousWallEnd[0] || currentWallEnd[1] !== previousWallEnd[1])
         ) {
@@ -611,6 +614,8 @@ export const WallTool: React.FC = () => {
     }
 
     const onGridClick = (event: GridEvent) => {
+      if (!wallPreviewRef.current) return
+
       if (buildingState.current === 1 && event.nativeEvent.detail >= 2) {
         stopDrafting()
         return
@@ -619,16 +624,16 @@ export const WallTool: React.FC = () => {
       const walls = getCurrentLevelWalls()
       const localClick: WallPlanPoint = [event.localPosition[0], event.localPosition[2]]
 
-      const clickStep = shiftPressed.current ? WALL_FINE_GRID_STEP : undefined
-      const bypassAlign = event.nativeEvent?.altKey === true
+      const bypassSnap = shiftPressed.current || event.nativeEvent?.shiftKey === true
+      const bypassAlign = event.nativeEvent?.altKey === true || bypassSnap
 
       if (buildingState.current === 0) {
         const snappedStart = alignPoint(
           snapWallDraftPointDetailed({
             point: localClick,
             walls,
-            step: clickStep,
-            magnetic: useEditor.getState().magneticSnap,
+            bypassSnap,
+            magnetic: !bypassSnap && useEditor.getState().magneticSnap,
           }).point,
           bypassAlign,
         )
@@ -651,14 +656,17 @@ export const WallTool: React.FC = () => {
         // `onGridMove` writes a real BoxGeometry skips that frame.
         setDraftMeasurement(null)
       } else if (buildingState.current === 1) {
+        const angleLocked = !bypassSnap
         const snappedEnd = alignPoint(
           snapWallDraftPointDetailed({
             point: localClick,
             walls,
-            step: clickStep,
-            magnetic: useEditor.getState().magneticSnap,
+            start: angleLocked ? [startingPoint.current.x, startingPoint.current.z] : undefined,
+            angleSnap: angleLocked,
+            bypassSnap,
+            magnetic: !bypassSnap && useEditor.getState().magneticSnap,
           }).point,
-          bypassAlign,
+          bypassAlign || angleLocked,
         )
         const dx = snappedEnd[0] - startingPoint.current.x
         const dz = snappedEnd[1] - startingPoint.current.z
@@ -684,6 +692,10 @@ export const WallTool: React.FC = () => {
         }
 
         const nextStart = createdWall.end
+        // Publish the resolved chain start so the 2D floor-plan draft
+        // chains its next segment from the same point (its own snap
+        // pipeline can resolve a slightly different endpoint).
+        useSegmentDraftChain.getState().setChainStart('wall', [nextStart[0], nextStart[1]])
         startingPoint.current.set(nextStart[0], event.localPosition[1], nextStart[1])
         endingPoint.current.copy(startingPoint.current)
         cursorRef.current?.position.copy(startingPoint.current)
@@ -698,7 +710,9 @@ export const WallTool: React.FC = () => {
         // BoxGeometry stays visible for a frame on top of the
         // freshly-committed real wall, producing a brief
         // double-paint at the new wall's position.
-        wallPreviewRef.current.visible = false
+        if (wallPreviewRef.current) {
+          wallPreviewRef.current.visible = false
+        }
         setDraftMeasurement(null)
       }
     }
@@ -711,6 +725,12 @@ export const WallTool: React.FC = () => {
       if (e.key === 'Shift') shiftPressed.current = false
     }
 
+    // Cmd-tabbing away mid-draft never delivers the keyup — reset so the
+    // angle lock isn't stuck off when focus returns.
+    const onBlur = () => {
+      shiftPressed.current = false
+    }
+
     const onCancel = () => {
       if (buildingState.current === 1) {
         markToolCancelConsumed()
@@ -723,6 +743,7 @@ export const WallTool: React.FC = () => {
     emitter.on('tool:cancel', onCancel)
     window.addEventListener('keydown', onKeyDown)
     window.addEventListener('keyup', onKeyUp)
+    window.addEventListener('blur', onBlur)
 
     return () => {
       emitter.off('grid:move', onGridMove)
@@ -730,8 +751,10 @@ export const WallTool: React.FC = () => {
       emitter.off('tool:cancel', onCancel)
       window.removeEventListener('keydown', onKeyDown)
       window.removeEventListener('keyup', onKeyUp)
+      window.removeEventListener('blur', onBlur)
       useAlignmentGuides.getState().clear()
       useWallSnapIndicator.getState().clear()
+      useSegmentDraftChain.getState().clear('wall')
     }
   }, [unit])
 
diff --git a/packages/nodes/src/window/floorplan-move.ts b/packages/nodes/src/window/floorplan-move.ts
index 24a9c8a0..cfa3c187 100644
--- a/packages/nodes/src/window/floorplan-move.ts
+++ b/packages/nodes/src/window/floorplan-move.ts
@@ -79,16 +79,17 @@ export const windowFloorplanMoveTarget: FloorplanMoveTarget<WindowNode> = ({ nod
 
       // Figma-style along-wall alignment first (edge-to-edge with other
       // openings / wall ends), winning over the 0.5m grid snap; falls back
-      // to grid when nothing aligns. Alt bypasses; Shift drops the grid snap.
-      const neighborX = modifiers.altKey
-        ? null
-        : snapLocalXToNeighbors({
-            wall: hit.wall,
-            localX: hit.localX,
-            width: node.width,
-            selfId: node.id as AnyNodeId,
-            nodes,
-          })
+      // to grid when nothing aligns. Alt bypasses alignment; Shift bypasses all snap.
+      const neighborX =
+        modifiers.altKey || modifiers.shiftKey
+          ? null
+          : snapLocalXToNeighbors({
+              wall: hit.wall,
+              localX: hit.localX,
+              width: node.width,
+              selfId: node.id as AnyNodeId,
+              nodes,
+            })
       const snappedLocalX = neighborX ?? (modifiers.shiftKey ? hit.localX : snapToHalf(hit.localX))
       const { clampedX, clampedY } = clampToWall(
         hit.wall,
diff --git a/packages/nodes/src/window/move-tool.tsx b/packages/nodes/src/window/move-tool.tsx
index 5da0e2fa..352c6e90 100644
--- a/packages/nodes/src/window/move-tool.tsx
+++ b/packages/nodes/src/window/move-tool.tsx
@@ -187,23 +187,31 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
       const rawLocalX = event.localPosition[0]
       const rawLocalY = event.localPosition[1]
       if (!dragAnchor || dragAnchor.wallId !== event.node.id) {
+        const bypassSnap = event.nativeEvent?.shiftKey === true
         dragAnchor = {
           wallId: event.node.id,
           rawX: rawLocalX,
           rawY: rawLocalY,
           startX: event.node.id === original.parentId ? original.position[0] : rawLocalX,
           startY:
-            event.node.id === original.parentId ? original.position[1] : snapToHalf(rawLocalY),
+            event.node.id === original.parentId
+              ? original.position[1]
+              : bypassSnap
+                ? rawLocalY
+                : snapToHalf(rawLocalY),
         }
       }
       const targetLocalX = dragAnchor.startX + (rawLocalX - dragAnchor.rawX)
-      const targetLocalY = snapToHalf(dragAnchor.startY + (rawLocalY - dragAnchor.rawY))
+      const targetRawLocalY = dragAnchor.startY + (rawLocalY - dragAnchor.rawY)
+      const targetLocalY =
+        event.nativeEvent?.shiftKey === true ? targetRawLocalY : snapToHalf(targetRawLocalY)
       const localX = resolveWallSlideAlignment({
         wallNode: event.node,
         rawLocalX: targetLocalX,
         width: movingWindowNode.width,
         candidates: alignmentCandidates,
-        bypass: event.nativeEvent?.altKey === true,
+        bypass: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
       const { clampedX, clampedY } = clampToWall(
         event.node,
@@ -409,7 +417,10 @@ const MoveWindowTool: React.FC<{ node: WindowNode }> = ({ node: movingWindowNode
         width: movingWindowNode.width,
         height: movingWindowNode.height,
         ignoreId: movingWindowNode.id,
-        vertical: { kind: 'free', snap: snapToHalf },
+        vertical: {
+          kind: 'free',
+          snap: event.nativeEvent?.shiftKey === true ? undefined : snapToHalf,
+        },
       })
 
     const updateRoofCursor = (target: RoofWallOpeningTarget, roof: RoofNode) => {
diff --git a/packages/nodes/src/window/tool.tsx b/packages/nodes/src/window/tool.tsx
index 2075d962..c627f7a2 100644
--- a/packages/nodes/src/window/tool.tsx
+++ b/packages/nodes/src/window/tool.tsx
@@ -128,9 +128,13 @@ const WindowTool: React.FC = () => {
         rawLocalX: event.localPosition[0],
         width,
         candidates: alignmentCandidates,
-        bypass: event.nativeEvent?.altKey === true,
+        bypass: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
-      const localY = snapToHalf(event.localPosition[1])
+      const localY =
+        event.nativeEvent?.shiftKey === true
+          ? event.localPosition[1]
+          : snapToHalf(event.localPosition[1])
 
       const { clampedX, clampedY } = clampToWall(event.node, localX, localY, width, height)
 
@@ -183,9 +187,13 @@ const WindowTool: React.FC = () => {
         rawLocalX: event.localPosition[0],
         width,
         candidates: alignmentCandidates,
-        bypass: event.nativeEvent?.altKey === true,
+        bypass: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
-      const localY = snapToHalf(event.localPosition[1])
+      const localY =
+        event.nativeEvent?.shiftKey === true
+          ? event.localPosition[1]
+          : snapToHalf(event.localPosition[1])
 
       const { clampedX, clampedY } = clampToWall(event.node, localX, localY, width, height)
 
@@ -277,9 +285,13 @@ const WindowTool: React.FC = () => {
         rawLocalX: event.localPosition[0],
         width: draftRef.current.width,
         candidates: alignmentCandidates,
-        bypass: event.nativeEvent?.altKey === true,
+        bypass: event.nativeEvent?.altKey === true || event.nativeEvent?.shiftKey === true,
+        bypassSnap: event.nativeEvent?.shiftKey === true,
       })
-      const localY = snapToHalf(event.localPosition[1])
+      const localY =
+        event.nativeEvent?.shiftKey === true
+          ? event.localPosition[1]
+          : snapToHalf(event.localPosition[1])
       const { clampedX, clampedY } = clampToWall(
         event.node,
         localX,
@@ -367,7 +379,10 @@ const WindowTool: React.FC = () => {
         width: draftRef.current?.width ?? 1.5,
         height: draftRef.current?.height ?? 1.5,
         ignoreId: draftRef.current?.id,
-        vertical: { kind: 'free', snap: snapToHalf },
+        vertical: {
+          kind: 'free',
+          snap: event.nativeEvent?.shiftKey === true ? undefined : snapToHalf,
+        },
       })
 
     const updateRoofCursor = (target: RoofWallOpeningTarget, roof: RoofNode) => {
diff --git a/packages/viewer/src/index.ts b/packages/viewer/src/index.ts
index 4624bcb8..158e4036 100644
--- a/packages/viewer/src/index.ts
+++ b/packages/viewer/src/index.ts
@@ -136,6 +136,13 @@ export {
   type StairBodyMaterials,
 } from './systems/stair/stair-materials'
 export { StairSystem } from './systems/stair/stair-system'
+// Pure opening-cutout profile math shared by the wall CSG pipeline and
+// roof-wall opening cuts in `@pascal-app/nodes` — keeps shaped holes
+// (arch / rounded / frameless opening) identical across both hosts.
+export {
+  buildOpeningCutoutGeometry,
+  hasFlatOpeningCutoutBottom,
+} from './systems/wall/opening-cutout-geometry'
 export { WallCutout } from './systems/wall/wall-cutout'
 export { getVisibleWallMaterials } from './systems/wall/wall-materials'
 // Wall internals re-exported so `@pascal-app/nodes`' registry-driven wall
diff --git a/packages/viewer/src/lib/csg-utils.test.ts b/packages/viewer/src/lib/csg-utils.test.ts
new file mode 100644
index 00000000..7063565b
--- /dev/null
+++ b/packages/viewer/src/lib/csg-utils.test.ts
@@ -0,0 +1,73 @@
+// @ts-expect-error — bun:test is provided by the Bun runtime; viewer does not
+// depend on @types/bun so the import type is unresolved at compile time.
+import { describe, expect, test } from 'bun:test'
+import * as THREE from 'three'
+import { ensureRenderableGeometryAttributes } from './csg-utils'
+
+describe('ensureRenderableGeometryAttributes', () => {
+  test('fills missing render attributes to match position count', () => {
+    const geometry = new THREE.BufferGeometry()
+    geometry.setAttribute(
+      'position',
+      new THREE.Float32BufferAttribute(new Float32Array([0, 0, 0, 1, 0, 0, 0, 1, 0]), 3),
+    )
+
+    ensureRenderableGeometryAttributes(geometry)
+
+    expect(geometry.getAttribute('position')?.count).toBe(3)
+    expect(geometry.getAttribute('normal')?.count).toBe(3)
+    expect(geometry.getAttribute('uv')?.count).toBe(3)
+    expect(geometry.getAttribute('uv2')?.count).toBe(3)
+  })
+
+  test('replaces render attributes with the wrong item size', () => {
+    const geometry = new THREE.BufferGeometry()
+    geometry.setAttribute(
+      'position',
+      new THREE.Float32BufferAttribute(new Float32Array([0, 0, 0, 1, 0, 0, 0, 1, 0]), 3),
+    )
+    geometry.setAttribute('uv', new THREE.Float32BufferAttribute(new Float32Array([0, 0, 0]), 1))
+    geometry.setAttribute('uv2', new THREE.Float32BufferAttribute(new Float32Array([0, 0, 0]), 1))
+
+    ensureRenderableGeometryAttributes(geometry)
+
+    expect(geometry.getAttribute('uv')?.itemSize).toBe(2)
+    expect(geometry.getAttribute('uv2')?.itemSize).toBe(2)
+    expect(geometry.getAttribute('uv')?.count).toBe(3)
+    expect(geometry.getAttribute('uv2')?.count).toBe(3)
+  })
+
+  test('copies uv into uv2 without depending on backing array layout', () => {
+    const geometry = new THREE.BufferGeometry()
+    geometry.setAttribute(
+      'position',
+      new THREE.Float32BufferAttribute(new Float32Array([0, 0, 0, 1, 0, 0, 0, 1, 0]), 3),
+    )
+    geometry.setAttribute(
+      'uv',
+      new THREE.InterleavedBufferAttribute(
+        new THREE.InterleavedBuffer(new Float32Array([0, 0, 7, 1, 0, 8, 0, 1, 9]), 3),
+        2,
+        0,
+      ),
+    )
+
+    ensureRenderableGeometryAttributes(geometry)
+
+    const uv2 = geometry.getAttribute('uv2')
+    expect(Array.from(uv2.array)).toEqual([0, 0, 1, 0, 0, 1])
+  })
+
+  test('replaces empty geometries with a degenerate renderable triangle', () => {
+    const geometry = new THREE.BufferGeometry()
+
+    ensureRenderableGeometryAttributes(geometry)
+
+    expect(geometry.getIndex()).toBeNull()
+    expect(geometry.groups).toHaveLength(0)
+    expect(geometry.getAttribute('position')?.count).toBe(3)
+    expect(geometry.getAttribute('normal')?.count).toBe(3)
+    expect(geometry.getAttribute('uv')?.count).toBe(3)
+    expect(geometry.getAttribute('uv2')?.count).toBe(3)
+  })
+})
diff --git a/packages/viewer/src/lib/csg-utils.ts b/packages/viewer/src/lib/csg-utils.ts
index 478eb3be..982b3a02 100644
--- a/packages/viewer/src/lib/csg-utils.ts
+++ b/packages/viewer/src/lib/csg-utils.ts
@@ -1,4 +1,4 @@
-import type * as THREE from 'three'
+import * as THREE from 'three'
 import { type Brush, Evaluator } from 'three-bvh-csg'
 import { computeBoundsTree } from 'three-mesh-bvh'
 
@@ -10,8 +10,81 @@ import { computeBoundsTree } from 'three-mesh-bvh'
  * in `@pascal-app/nodes` import these through the public surface.
  */
 
+function zeroAttribute(count: number, itemSize: number) {
+  return new THREE.Float32BufferAttribute(new Float32Array(count * itemSize), itemSize)
+}
+
+function upNormalAttribute(count: number) {
+  const values = new Float32Array(count * 3)
+  for (let index = 0; index < count; index += 1) {
+    values[index * 3 + 1] = 1
+  }
+  return new THREE.Float32BufferAttribute(values, 3)
+}
+
+function ensureAttributeCount(
+  geometry: THREE.BufferGeometry,
+  name: string,
+  itemSize: number,
+  count: number,
+) {
+  const attribute = geometry.getAttribute(name)
+  if (attribute?.count === count && attribute.itemSize === itemSize) return
+
+  geometry.setAttribute(name, zeroAttribute(count, itemSize))
+}
+
+function copyVec2Attribute(attribute: THREE.BufferAttribute | THREE.InterleavedBufferAttribute) {
+  const values = new Float32Array(attribute.count * 2)
+  for (let index = 0; index < attribute.count; index += 1) {
+    values[index * 2] = attribute.getX(index)
+    values[index * 2 + 1] = attribute.getY(index)
+  }
+  return new THREE.Float32BufferAttribute(values, 2)
+}
+
+export function ensureRenderableGeometryAttributes(
+  geometry: THREE.BufferGeometry,
+): THREE.BufferGeometry {
+  const position = geometry.getAttribute('position')
+  if (!position || position.count === 0 || position.itemSize !== 3) {
+    geometry.setIndex(null)
+    geometry.clearGroups()
+    geometry.setAttribute('position', zeroAttribute(3, 3))
+    geometry.setAttribute('normal', upNormalAttribute(3))
+    geometry.setAttribute('uv', zeroAttribute(3, 2))
+    geometry.setAttribute('uv2', zeroAttribute(3, 2))
+    return geometry
+  }
+
+  const count = position.count
+  const normal = geometry.getAttribute('normal')
+  if (normal?.count !== count || normal.itemSize !== 3) {
+    geometry.deleteAttribute('normal')
+    try {
+      geometry.computeVertexNormals()
+    } catch {
+      geometry.deleteAttribute('normal')
+    }
+  }
+
+  const computedNormal = geometry.getAttribute('normal')
+  if (computedNormal?.count !== count || computedNormal.itemSize !== 3) {
+    geometry.setAttribute('normal', upNormalAttribute(count))
+  }
+  ensureAttributeCount(geometry, 'uv', 2, count)
+
+  const uv = geometry.getAttribute('uv')
+  const uv2 = geometry.getAttribute('uv2')
+  if (uv2?.count !== count || uv2.itemSize !== 2) {
+    geometry.setAttribute('uv2', copyVec2Attribute(uv))
+  }
+
+  return geometry
+}
+
 export function csgGeometry(brush: Brush): THREE.BufferGeometry {
-  return brush.geometry as unknown as THREE.BufferGeometry
+  return ensureRenderableGeometryAttributes(brush.geometry as unknown as THREE.BufferGeometry)
 }
 
 export function csgMaterials(brush: Brush): THREE.Material[] {
@@ -22,7 +95,7 @@ export function csgMaterials(brush: Brush): THREE.Material[] {
 export const csgEvaluator = new Evaluator()
 csgEvaluator.useGroups = true
 ;(csgEvaluator as unknown as { consolidateGroups: boolean }).consolidateGroups = false
-csgEvaluator.attributes = ['position', 'normal', 'uv']
+csgEvaluator.attributes = ['position', 'normal', 'uv', 'uv2']
 
 export function computeGeometryBoundsTree(geometry: THREE.BufferGeometry) {
   ;(geometry as unknown as { computeBoundsTree: typeof computeBoundsTree }).computeBoundsTree =
@@ -33,6 +106,7 @@ export function computeGeometryBoundsTree(geometry: THREE.BufferGeometry) {
 }
 
 export function prepareBrushForCSG(brush: Brush) {
+  ensureRenderableGeometryAttributes(brush.geometry)
   computeGeometryBoundsTree(brush.geometry)
   brush.updateMatrixWorld()
 }
diff --git a/packages/viewer/src/lib/materials.ts b/packages/viewer/src/lib/materials.ts
index 090971fa..5229c603 100644
--- a/packages/viewer/src/lib/materials.ts
+++ b/packages/viewer/src/lib/materials.ts
@@ -86,10 +86,14 @@ export const glassMaterial = new MeshLambertNodeMaterial({
   side: THREE.FrontSide,
 })
 
+function resolveNodeMaterialSide(side: THREE.Side): THREE.Side {
+  return side === THREE.DoubleSide ? THREE.FrontSide : side
+}
+
 const sideMap: Record<MaterialProperties['side'], THREE.Side> = {
   front: THREE.FrontSide,
   back: THREE.BackSide,
-  double: THREE.DoubleSide,
+  double: THREE.FrontSide,
 }
 
 const materialCache = new Map<string, THREE.Material>()
@@ -366,12 +370,13 @@ function applyMaterialMapProperties(
   }
   material.transparent = mapProperties.transparent
   material.opacity = mapProperties.opacity
-  material.side =
+  material.side = resolveNodeMaterialSide(
     mapProperties.side === 0
       ? THREE.FrontSide
       : mapProperties.side === 1
         ? THREE.BackSide
-        : THREE.DoubleSide
+        : THREE.DoubleSide,
+  )
   applyTexturePropertiesToMaterial(material, mapProperties)
   material.needsUpdate = true
 }
@@ -487,10 +492,11 @@ export function createDefaultMaterial(
   shading: RenderShading = 'rendered',
   side: THREE.Side = THREE.FrontSide,
 ): THREE.Material {
+  const resolvedSide = resolveNodeMaterialSide(side)
   if (shading === 'solid') {
     return new MeshLambertNodeMaterial({
       color,
-      side,
+      side: resolvedSide,
     })
   }
 
@@ -498,7 +504,7 @@ export function createDefaultMaterial(
     color,
     roughness,
     metalness: 0,
-    side,
+    side: resolvedSide,
   })
 }
 
@@ -532,7 +538,8 @@ export function createSurfaceRoleMaterial(
   // on both gable faces on the first frame). Callers that need both sides
   // visible (e.g. dormer back gable) must rotate the host mesh 180° so the
   // FrontSide faces the viewer.
-  const resolvedSide = role === 'glazing' ? THREE.FrontSide : side
+  const resolvedSide =
+    role === 'glazing' ? THREE.FrontSide : resolveNodeMaterialSide(side ?? THREE.FrontSide)
   const cacheKey = `${role}-${preset}-${resolvedSide}-${sceneThemeId ?? 'base'}`
   const cached = surfaceRoleMaterialCache.get(cacheKey)
   if (cached) return cached
diff --git a/packages/viewer/src/systems/ceiling/ceiling-system.tsx b/packages/viewer/src/systems/ceiling/ceiling-system.tsx
index 93615032..3b5fd63c 100644
--- a/packages/viewer/src/systems/ceiling/ceiling-system.tsx
+++ b/packages/viewer/src/systems/ceiling/ceiling-system.tsx
@@ -135,6 +135,7 @@ export function generateCeilingGeometry(
     degenerate.setAttribute('position', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
     degenerate.setAttribute('normal', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
     degenerate.setAttribute('uv', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
+    degenerate.setAttribute('uv2', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
     return degenerate
   }
 
diff --git a/packages/viewer/src/systems/roof/roof-system.tsx b/packages/viewer/src/systems/roof/roof-system.tsx
index 323cca7a..3df1ad1d 100644
--- a/packages/viewer/src/systems/roof/roof-system.tsx
+++ b/packages/viewer/src/systems/roof/roof-system.tsx
@@ -17,6 +17,7 @@ import * as THREE from 'three'
 import { mergeVertices } from 'three/examples/jsm/utils/BufferGeometryUtils.js'
 import { ADDITION, Brush, Evaluator, SUBTRACTION } from 'three-bvh-csg'
 import { computeBoundsTree } from 'three-mesh-bvh'
+import { ensureRenderableGeometryAttributes } from '../../lib/csg-utils'
 
 function csgGeometry(brush: Brush): THREE.BufferGeometry {
   return brush.geometry as unknown as THREE.BufferGeometry
@@ -30,7 +31,7 @@ function csgMaterials(brush: Brush): THREE.Material[] {
 const csgEvaluator = new Evaluator()
 csgEvaluator.useGroups = true
 ;(csgEvaluator as any).consolidateGroups = false // shared dummyMats across brushes causes consolidation to misalign groupIndices vs groupOrder indices → crash
-csgEvaluator.attributes = ['position', 'normal', 'uv']
+csgEvaluator.attributes = ['position', 'normal', 'uv', 'uv2']
 
 function computeGeometryBoundsTree(geometry: THREE.BufferGeometry) {
   ;(geometry as any).computeBoundsTree = computeBoundsTree
@@ -38,6 +39,7 @@ function computeGeometryBoundsTree(geometry: THREE.BufferGeometry) {
 }
 
 function prepareBrushForCSG(brush: Brush) {
+  ensureRenderableGeometryAttributes(brush.geometry)
   computeGeometryBoundsTree(brush.geometry)
   brush.updateMatrixWorld()
 }
@@ -176,6 +178,10 @@ export const RoofSystem = () => {
                 'uv',
                 new THREE.Float32BufferAttribute(new Float32Array(6), 2),
               )
+              placeholder.setAttribute(
+                'uv2',
+                new THREE.Float32BufferAttribute(new Float32Array(6), 2),
+              )
               computeGeometryBoundsTree(placeholder)
               mesh.geometry = placeholder
             }
@@ -299,6 +305,7 @@ function subtractAccessoryCuts(
     welded.clearGroups()
     welded.addGroup(0, idxCount, 0)
     welded.computeVertexNormals()
+    ensureRenderableGeometryAttributes(welded)
     computeGeometryBoundsTree(welded)
     const cut = new Brush(welded, dummyMats[0])
     cut.updateMatrixWorld()
@@ -434,11 +441,16 @@ function updateMergedRoofGeometry(
   if (totalShinSlab && totalDeckSlab && totalWall && totalInner) {
     try {
       const finalShinTrimmed = csgEvaluator.evaluate(totalShinSlab, totalInner, SUBTRACTION)
+      prepareBrushForCSG(finalShinTrimmed)
       const finalDeckTrimmed = csgEvaluator.evaluate(totalDeckSlab, totalInner, SUBTRACTION)
+      prepareBrushForCSG(finalDeckTrimmed)
       const finalWallTrimmed = csgEvaluator.evaluate(totalWall, totalInner, SUBTRACTION)
+      prepareBrushForCSG(finalWallTrimmed)
 
       const shinDeck = csgEvaluator.evaluate(finalShinTrimmed, finalDeckTrimmed, ADDITION)
+      prepareBrushForCSG(shinDeck)
       const combined = csgEvaluator.evaluate(shinDeck, finalWallTrimmed, ADDITION)
+      prepareBrushForCSG(combined)
 
       const resultGeo = csgGeometry(combined)
       if (geometryHasNaNPositions(resultGeo)) {
@@ -472,7 +484,7 @@ function updateMergedRoofGeometry(
       }
 
       resultGeo.computeVertexNormals()
-      ensureUv2Attribute(resultGeo)
+      ensureRenderableGeometryAttributes(resultGeo)
       mergedMesh.geometry.dispose()
       mergedMesh.geometry = resultGeo
 
@@ -765,6 +777,7 @@ export function getRoofSegmentBrushes(
     // when a group exists but covers no triangles (can happen after mergeVertices)
     geo.groups = geo.groups.filter((g) => g.count > 0)
     if (geo.groups.length === 0) return null
+    ensureRenderableGeometryAttributes(geo)
     computeGeometryBoundsTree(geo)
     const brush = new Brush(geo, dummyMats)
     brush.updateMatrixWorld()
@@ -810,7 +823,9 @@ export function getRoofSegmentBrushes(
   if (deckTopBrush && deckBotBrush && wallBrush && innerBrush && shinTopBrush && shinBotBrush) {
     try {
       const deckSlab = csgEvaluator.evaluate(deckTopBrush, deckBotBrush, SUBTRACTION)
+      prepareBrushForCSG(deckSlab)
       const shinSlab = csgEvaluator.evaluate(shinTopBrush, shinBotBrush, SUBTRACTION)
+      prepareBrushForCSG(shinSlab)
 
       deckTopBrush.geometry.dispose()
       deckBotBrush.geometry.dispose()
@@ -852,8 +867,11 @@ export function generateRoofSegmentGeometry(
 
   try {
     const hollowWall = csgEvaluator.evaluate(wallBrush, innerBrush, SUBTRACTION)
+    prepareBrushForCSG(hollowWall)
     const shinDeck = csgEvaluator.evaluate(shinSlab, deckSlab, ADDITION)
+    prepareBrushForCSG(shinDeck)
     const combined = csgEvaluator.evaluate(shinDeck, hollowWall, ADDITION)
+    prepareBrushForCSG(combined)
 
     resultGeo = csgGeometry(combined)
 
@@ -889,7 +907,7 @@ export function generateRoofSegmentGeometry(
   innerBrush.geometry.dispose()
 
   resultGeo.computeVertexNormals()
-  ensureUv2Attribute(resultGeo)
+  ensureRenderableGeometryAttributes(resultGeo)
   return resultGeo
 }
 
@@ -1296,7 +1314,7 @@ function createGeometryFromFaces(
   const mergedGeo = mergeVertices(geometry, 1e-4)
   geometry.dispose()
 
-  ensureUv2Attribute(mergedGeo)
+  ensureRenderableGeometryAttributes(mergedGeo)
   return mergedGeo
 }
 
@@ -1330,13 +1348,6 @@ function pushRoofUv(uvs: number[], point: THREE.Vector3, normal: THREE.Vector3)
   uvs.push(_uvFaceNormal.z >= 0 ? point.x : -point.x, -point.y)
 }
 
-function ensureUv2Attribute(geometry: THREE.BufferGeometry) {
-  const uv = geometry.getAttribute('uv')
-  if (!uv) return
-
-  geometry.setAttribute('uv2', new THREE.Float32BufferAttribute(Array.from(uv.array), 2))
-}
-
 // ─── Skylight cutout ─────────────────────────────────────────────────
 export type SurfaceFrame = {
   point: THREE.Vector3
diff --git a/packages/viewer/src/systems/stair/stair-system.tsx b/packages/viewer/src/systems/stair/stair-system.tsx
index f5d09f7c..19bd62a2 100644
--- a/packages/viewer/src/systems/stair/stair-system.tsx
+++ b/packages/viewer/src/systems/stair/stair-system.tsx
@@ -533,6 +533,7 @@ function createEmptyGeometry(): THREE.BufferGeometry {
   geometry.setAttribute('position', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
   geometry.setAttribute('normal', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
   geometry.setAttribute('uv', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
+  geometry.setAttribute('uv2', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
   geometry.addGroup(0, 0, STAIR_TREAD_MATERIAL_INDEX)
   geometry.addGroup(0, 0, STAIR_SIDE_MATERIAL_INDEX)
   return geometry
diff --git a/packages/viewer/src/systems/wall/opening-cutout-geometry.test.ts b/packages/viewer/src/systems/wall/opening-cutout-geometry.test.ts
new file mode 100644
index 00000000..dc25c38b
--- /dev/null
+++ b/packages/viewer/src/systems/wall/opening-cutout-geometry.test.ts
@@ -0,0 +1,210 @@
+// @ts-expect-error — bun:test is provided by the Bun runtime; viewer does not
+// depend on @types/bun so the import type is unresolved at compile time.
+import { describe, expect, test } from 'bun:test'
+import { DoorNode, WindowNode } from '@pascal-app/core'
+import type * as THREE from 'three'
+import {
+  buildOpeningCutoutGeometry,
+  buildOpeningCutoutShape,
+  hasFlatOpeningCutoutBottom,
+} from './opening-cutout-geometry'
+
+function containsPoint(points: THREE.Vector2[], x: number, y: number) {
+  return points.some((point) => Math.abs(point.x - x) < 1e-6 && Math.abs(point.y - y) < 1e-6)
+}
+
+function getBounds(points: THREE.Vector2[]) {
+  let minX = Number.POSITIVE_INFINITY
+  let maxX = Number.NEGATIVE_INFINITY
+  let minY = Number.POSITIVE_INFINITY
+  let maxY = Number.NEGATIVE_INFINITY
+  for (const point of points) {
+    minX = Math.min(minX, point.x)
+    maxX = Math.max(maxX, point.x)
+    minY = Math.min(minY, point.y)
+    maxY = Math.max(maxY, point.y)
+  }
+  return { minX, maxX, minY, maxY }
+}
+
+describe('buildOpeningCutoutShape', () => {
+  test('rectangle profile passes the rect through unchanged', () => {
+    const door = DoorNode.parse({})
+    const rect = { left: 1.2, right: 2.1, bottom: 0, top: 2.1 }
+
+    const points = buildOpeningCutoutShape(door, rect).getPoints()
+
+    expect(containsPoint(points, rect.left, rect.bottom)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.bottom)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.top)).toBe(true)
+    expect(containsPoint(points, rect.left, rect.top)).toBe(true)
+
+    const bounds = getBounds(points)
+    expect(bounds.minX).toBeCloseTo(rect.left, 9)
+    expect(bounds.maxX).toBeCloseTo(rect.right, 9)
+    expect(bounds.minY).toBeCloseTo(rect.bottom, 9)
+    expect(bounds.maxY).toBeCloseTo(rect.top, 9)
+  })
+
+  test('door rounded profile rounds only the top corners', () => {
+    const door = DoorNode.parse({ openingShape: 'rounded', cornerRadius: 0.2 })
+    const rect = { left: -0.45, right: 0.45, bottom: 0, top: 2.1 }
+
+    const points = buildOpeningCutoutShape(door, rect).getPoints()
+
+    expect(containsPoint(points, rect.left, rect.bottom)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.bottom)).toBe(true)
+    expect(containsPoint(points, rect.left, rect.top)).toBe(false)
+    expect(containsPoint(points, rect.right, rect.top)).toBe(false)
+    expect(containsPoint(points, rect.left, rect.top - 0.2)).toBe(true)
+    expect(containsPoint(points, rect.left + 0.2, rect.top)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.top - 0.2)).toBe(true)
+    expect(containsPoint(points, rect.right - 0.2, rect.top)).toBe(true)
+  })
+
+  test('window rounded profile rounds all four corners', () => {
+    const window = WindowNode.parse({ openingShape: 'rounded', cornerRadius: 0.2 })
+    const rect = { left: -0.75, right: 0.75, bottom: 0.9, top: 2.4 }
+
+    const points = buildOpeningCutoutShape(window, rect).getPoints()
+
+    expect(containsPoint(points, rect.left, rect.bottom)).toBe(false)
+    expect(containsPoint(points, rect.right, rect.bottom)).toBe(false)
+    expect(containsPoint(points, rect.left, rect.top)).toBe(false)
+    expect(containsPoint(points, rect.right, rect.top)).toBe(false)
+    expect(containsPoint(points, rect.left + 0.2, rect.bottom)).toBe(true)
+    expect(containsPoint(points, rect.left, rect.bottom + 0.2)).toBe(true)
+    expect(containsPoint(points, rect.right - 0.2, rect.top)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.top - 0.2)).toBe(true)
+
+    const bounds = getBounds(points)
+    expect(bounds.minX).toBeCloseTo(rect.left, 9)
+    expect(bounds.maxX).toBeCloseTo(rect.right, 9)
+    expect(bounds.minY).toBeCloseTo(rect.bottom, 9)
+    expect(bounds.maxY).toBeCloseTo(rect.top, 9)
+  })
+
+  test('shared corner radius is clamped to the opening half-extent', () => {
+    const window = WindowNode.parse({ openingShape: 'rounded', cornerRadius: 10 })
+    const rect = { left: -0.75, right: 0.75, bottom: 0.9, top: 2.4 }
+
+    const points = buildOpeningCutoutShape(window, rect).getPoints()
+
+    // 1.5 × 1.5 opening → radius clamps to 0.75; arcs meet at edge midpoints.
+    expect(containsPoint(points, rect.left, rect.bottom + 0.75)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.top - 0.75)).toBe(true)
+
+    const bounds = getBounds(points)
+    expect(bounds.minX).toBeCloseTo(rect.left, 9)
+    expect(bounds.maxX).toBeCloseTo(rect.right, 9)
+  })
+
+  test('individual radii normalize when their sum exceeds the opening width', () => {
+    const window = WindowNode.parse({
+      openingShape: 'rounded',
+      openingRadiusMode: 'individual',
+      openingCornerRadii: [4, 4, 0, 0],
+    })
+    const rect = { left: -0.5, right: 0.5, bottom: 0, top: 2 }
+
+    const points = buildOpeningCutoutShape(window, rect).getPoints()
+
+    // Width 1 with top radii summing to 8 → scaled down to 0.5 each.
+    expect(containsPoint(points, rect.left, rect.top - 0.5)).toBe(true)
+    expect(containsPoint(points, rect.left + 0.5, rect.top)).toBe(true)
+    expect(containsPoint(points, rect.left, rect.bottom)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.bottom)).toBe(true)
+  })
+
+  test('arch profile springs at top - archHeight and peaks at the rect top', () => {
+    const door = DoorNode.parse({ openingShape: 'arch', archHeight: 0.45 })
+    const rect = { left: -0.45, right: 0.45, bottom: 0, top: 2.1 }
+
+    const points = buildOpeningCutoutShape(door, rect).getPoints()
+
+    expect(containsPoint(points, rect.left, rect.bottom)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.bottom)).toBe(true)
+    expect(containsPoint(points, rect.right, rect.top - 0.45)).toBe(true)
+    expect(containsPoint(points, 0, rect.top)).toBe(true)
+    expect(containsPoint(points, rect.left, rect.top)).toBe(false)
+    expect(containsPoint(points, rect.right, rect.top)).toBe(false)
+  })
+
+  test('profiles are origin-agnostic — offset rects yield translated points', () => {
+    const window = WindowNode.parse({ openingShape: 'rounded', cornerRadius: 0.2 })
+    const centered = buildOpeningCutoutShape(window, {
+      left: -0.75,
+      right: 0.75,
+      bottom: -0.75,
+      top: 0.75,
+    }).getPoints()
+    const offset = buildOpeningCutoutShape(window, {
+      left: 2.25,
+      right: 3.75,
+      bottom: 0.9,
+      top: 2.4,
+    }).getPoints()
+
+    for (const point of centered) {
+      expect(containsPoint(offset, point.x + 3, point.y + 1.65)).toBe(true)
+    }
+    for (const point of offset) {
+      expect(containsPoint(centered, point.x - 3, point.y - 1.65)).toBe(true)
+    }
+  })
+})
+
+describe('buildOpeningCutoutGeometry', () => {
+  test('extrudes the rect through the depth, centered on the mid-plane', () => {
+    const door = DoorNode.parse({})
+    const geometry = buildOpeningCutoutGeometry(
+      door,
+      { left: -0.45, right: 0.45, bottom: -1.05, top: 1.05 },
+      0.24,
+      0.1,
+    )
+
+    geometry.computeBoundingBox()
+    // Float32 position buffer → ~1e-7 relative precision.
+    const box = geometry.boundingBox!
+    expect(box.min.x).toBeCloseTo(-0.45, 6)
+    expect(box.max.x).toBeCloseTo(0.45, 6)
+    expect(box.min.y).toBeCloseTo(-1.05, 6)
+    expect(box.max.y).toBeCloseTo(1.05, 6)
+    expect(box.min.z).toBeCloseTo(-0.12, 6)
+    expect(box.max.z).toBeCloseTo(0.12, 6)
+  })
+})
+
+describe('hasFlatOpeningCutoutBottom', () => {
+  test('flat for rectangles, arches, and door rounded (top-only radii)', () => {
+    expect(hasFlatOpeningCutoutBottom(DoorNode.parse({}))).toBe(true)
+    expect(hasFlatOpeningCutoutBottom(WindowNode.parse({ openingShape: 'arch' }))).toBe(true)
+    expect(hasFlatOpeningCutoutBottom(DoorNode.parse({ openingShape: 'rounded' }))).toBe(true)
+  })
+
+  test('rounded windows depend on their bottom radii', () => {
+    expect(hasFlatOpeningCutoutBottom(WindowNode.parse({ openingShape: 'rounded' }))).toBe(false)
+    expect(
+      hasFlatOpeningCutoutBottom(WindowNode.parse({ openingShape: 'rounded', cornerRadius: 0 })),
+    ).toBe(true)
+    expect(
+      hasFlatOpeningCutoutBottom(
+        WindowNode.parse({
+          openingShape: 'rounded',
+          openingRadiusMode: 'individual',
+          openingCornerRadii: [0.2, 0.2, 0, 0],
+        }),
+      ),
+    ).toBe(true)
+    expect(
+      hasFlatOpeningCutoutBottom(
+        WindowNode.parse({
+          openingShape: 'rounded',
+          openingRadiusMode: 'individual',
+          openingCornerRadii: [0.2, 0.2, 0.2, 0.2],
+        }),
+      ),
+    ).toBe(false)
+  })
+})
diff --git a/packages/viewer/src/systems/wall/opening-cutout-geometry.ts b/packages/viewer/src/systems/wall/opening-cutout-geometry.ts
new file mode 100644
index 00000000..ea2e8c01
--- /dev/null
+++ b/packages/viewer/src/systems/wall/opening-cutout-geometry.ts
@@ -0,0 +1,224 @@
+import type { DoorNode, WindowNode } from '@pascal-app/core'
+import * as THREE from 'three'
+
+export type OpeningCutoutNode = DoorNode | WindowNode
+
+export type OpeningCutoutRect = {
+  left: number
+  right: number
+  bottom: number
+  top: number
+}
+
+type CornerRadii = {
+  topLeft: number
+  topRight: number
+  bottomRight: number
+  bottomLeft: number
+}
+
+/**
+ * Pure cutout profile for a shaped door / window opening. `rect` is in
+ * the caller's coordinate frame — the wall CSG pipeline passes wall-local
+ * coords, the roof-wall pipeline an origin-centered rect — so the same
+ * radii / arch math serves both hosts.
+ */
+export function buildOpeningCutoutShape(
+  opening: OpeningCutoutNode,
+  rect: OpeningCutoutRect,
+): THREE.Shape {
+  const { left, right, bottom, top } = rect
+  const width = Math.max(right - left, 1e-6)
+  const height = Math.max(top - bottom, 1e-6)
+  const shape = new THREE.Shape()
+
+  if (opening.openingShape === 'arch') {
+    const halfWidth = width / 2
+    const centerX = (left + right) / 2
+    const archHeight = Math.min(Math.max(opening.archHeight ?? width / 2, 0.01), height)
+    const springY = top - archHeight
+    const segments = 32
+
+    shape.moveTo(left, bottom)
+    shape.lineTo(right, bottom)
+    shape.lineTo(right, springY)
+    for (let index = 1; index <= segments; index += 1) {
+      const x = right + (left - right) * (index / segments)
+      const normalizedX = Math.min(Math.abs((x - centerX) / halfWidth), 1)
+      const y = springY + archHeight * Math.sqrt(Math.max(1 - normalizedX * normalizedX, 0))
+      shape.lineTo(x, y)
+    }
+    shape.lineTo(left, bottom)
+    shape.closePath()
+    return shape
+  }
+
+  if (opening.openingShape === 'rounded') {
+    const radii = getRoundedOpeningRadii(opening, width, height)
+    applyRoundedOpeningShape(shape, left, right, bottom, top, radii)
+    return shape
+  }
+
+  shape.moveTo(left, bottom)
+  shape.lineTo(right, bottom)
+  shape.lineTo(right, top)
+  shape.lineTo(left, top)
+  shape.closePath()
+  return shape
+}
+
+export function buildOpeningCutoutGeometry(
+  opening: OpeningCutoutNode,
+  rect: OpeningCutoutRect,
+  depth: number,
+  wallThickness: number,
+): THREE.BufferGeometry {
+  const shape = buildOpeningCutoutShape(opening, rect)
+  const bevelSize =
+    opening.openingShape === 'rounded'
+      ? Math.min(
+          Math.max(opening.openingRevealRadius ?? 0.025, 0),
+          Math.max(wallThickness * 0.45, 0.001),
+          Math.max((opening.cornerRadius ?? 0.15) * 0.45, 0.001),
+        )
+      : 0
+  const geometry = new THREE.ExtrudeGeometry(shape, {
+    depth,
+    bevelEnabled: bevelSize > 0,
+    bevelSegments: bevelSize > 0 ? 8 : 0,
+    bevelSize,
+    bevelThickness: bevelSize,
+    curveSegments: 24,
+  })
+
+  geometry.translate(0, 0, -depth / 2)
+  return geometry
+}
+
+/**
+ * Whether the cutout profile's bottom edge is a flat chord. Cuts whose
+ * bottom sits coplanar with the host wall base get extended slightly
+ * downward to keep CSG away from coplanar faces — but only a flat chord
+ * may extend; shifting a rounded bottom would distort the profile.
+ */
+export function hasFlatOpeningCutoutBottom(opening: OpeningCutoutNode): boolean {
+  if (opening.openingShape !== 'rounded' || opening.type !== 'window') return true
+
+  if (opening.openingRadiusMode === 'individual') {
+    const [, , bottomRight = 0, bottomLeft = 0] = opening.openingCornerRadii ?? [
+      0.15, 0.15, 0.15, 0.15,
+    ]
+    return bottomRight <= 1e-6 && bottomLeft <= 1e-6
+  }
+
+  return Math.max(opening.cornerRadius ?? 0.15, 0) <= 1e-6
+}
+
+function getRoundedOpeningRadii(
+  opening: OpeningCutoutNode,
+  width: number,
+  height: number,
+): CornerRadii {
+  if (opening.type !== 'window') {
+    if (opening.openingRadiusMode === 'individual') {
+      const [topLeft = 0, topRight = 0] = opening.openingTopRadii ?? [0.15, 0.15]
+
+      return normalizeCornerRadii(
+        {
+          topLeft: Math.max(topLeft, 0),
+          topRight: Math.max(topRight, 0),
+          bottomRight: 0,
+          bottomLeft: 0,
+        },
+        width,
+        height,
+      )
+    }
+
+    const maxRadius = Math.min(width / 2, height)
+    const radius = Math.min(Math.max(opening.cornerRadius ?? 0.15, 0), maxRadius)
+    return { topLeft: radius, topRight: radius, bottomRight: 0, bottomLeft: 0 }
+  }
+
+  if (opening.openingRadiusMode === 'individual') {
+    const [topLeft = 0, topRight = 0, bottomRight = 0, bottomLeft = 0] =
+      opening.openingCornerRadii ?? [0.15, 0.15, 0.15, 0.15]
+
+    return normalizeCornerRadii(
+      {
+        topLeft: Math.max(topLeft, 0),
+        topRight: Math.max(topRight, 0),
+        bottomRight: Math.max(bottomRight, 0),
+        bottomLeft: Math.max(bottomLeft, 0),
+      },
+      width,
+      height,
+    )
+  }
+
+  const maxRadius = Math.min(width / 2, height / 2)
+  const radius = Math.min(Math.max(opening.cornerRadius ?? 0.15, 0), maxRadius)
+  return { topLeft: radius, topRight: radius, bottomRight: radius, bottomLeft: radius }
+}
+
+function normalizeCornerRadii(radii: CornerRadii, width: number, height: number): CornerRadii {
+  const next = { ...radii }
+  const maxScale = Math.min(
+    1,
+    width / Math.max(next.topLeft + next.topRight, 1e-6),
+    width / Math.max(next.bottomLeft + next.bottomRight, 1e-6),
+    height / Math.max(next.topLeft + next.bottomLeft, 1e-6),
+    height / Math.max(next.topRight + next.bottomRight, 1e-6),
+  )
+
+  if (maxScale < 1) {
+    next.topLeft *= maxScale
+    next.topRight *= maxScale
+    next.bottomRight *= maxScale
+    next.bottomLeft *= maxScale
+  }
+
+  return next
+}
+
+function applyRoundedOpeningShape(
+  shape: THREE.Shape,
+  left: number,
+  right: number,
+  bottom: number,
+  top: number,
+  radii: CornerRadii,
+) {
+  const { topLeft, topRight, bottomRight, bottomLeft } = radii
+
+  shape.moveTo(left + bottomLeft, bottom)
+  shape.lineTo(right - bottomRight, bottom)
+  if (bottomRight > 1e-6) {
+    shape.absarc(right - bottomRight, bottom + bottomRight, bottomRight, -Math.PI / 2, 0, false)
+  } else {
+    shape.lineTo(right, bottom)
+  }
+
+  shape.lineTo(right, top - topRight)
+  if (topRight > 1e-6) {
+    shape.absarc(right - topRight, top - topRight, topRight, 0, Math.PI / 2, false)
+  } else {
+    shape.lineTo(right, top)
+  }
+
+  shape.lineTo(left + topLeft, top)
+  if (topLeft > 1e-6) {
+    shape.absarc(left + topLeft, top - topLeft, topLeft, Math.PI / 2, Math.PI, false)
+  } else {
+    shape.lineTo(left, top)
+  }
+
+  shape.lineTo(left, bottom + bottomLeft)
+  if (bottomLeft > 1e-6) {
+    shape.absarc(left + bottomLeft, bottom + bottomLeft, bottomLeft, Math.PI, Math.PI * 1.5, false)
+  } else {
+    shape.lineTo(left, bottom)
+  }
+
+  shape.closePath()
+}
diff --git a/packages/viewer/src/systems/wall/wall-system.tsx b/packages/viewer/src/systems/wall/wall-system.tsx
index 10d58413..840075a0 100644
--- a/packages/viewer/src/systems/wall/wall-system.tsx
+++ b/packages/viewer/src/systems/wall/wall-system.tsx
@@ -28,9 +28,12 @@ import { useFrame } from '@react-three/fiber'
 import * as THREE from 'three'
 import { Brush, Evaluator, SUBTRACTION } from 'three-bvh-csg'
 import { computeBoundsTree } from 'three-mesh-bvh'
+import { ensureRenderableGeometryAttributes, prepareBrushForCSG } from '../../lib/csg-utils'
+import { buildOpeningCutoutGeometry } from './opening-cutout-geometry'
 
 // Reusable CSG evaluator for better performance
 const csgEvaluator = new Evaluator()
+csgEvaluator.attributes = ['position', 'normal', 'uv', 'uv2']
 const CURVED_WALL_3D_ENDPOINT_INSET = 0.0015
 const WALL_FACE_NORMAL_Y_EPSILON = 0.6
 const WALL_FACE_EDGE_DISTANCE_EPSILON = 0.003
@@ -52,13 +55,6 @@ type TaggedWallBoundaryEdge = {
   tag: WallBoundaryEdgeTag
 }
 
-function ensureUv2Attribute(geometry: THREE.BufferGeometry) {
-  const uv = geometry.getAttribute('uv')
-  if (!uv) return
-
-  geometry.setAttribute('uv2', new THREE.Float32BufferAttribute(Array.from(uv.array), 2))
-}
-
 function insetCurvedWallBoundaryPointsFor3D(
   wall: WallNode,
   boundaryPoints: ReturnType<typeof getWallMiterBoundaryPoints>,
@@ -671,7 +667,7 @@ export function generateExtrudedWall(
   geometry.rotateX(-Math.PI / 2)
   geometry.computeVertexNormals()
   assignWallMaterialGroups(geometry, wallNode, boundaryEdges)
-  ensureUv2Attribute(geometry)
+  ensureRenderableGeometryAttributes(geometry)
 
   // Apply CSG subtraction for cutouts (doors/windows)
   const cutoutBrushes = collectCutoutBrushes(wallNode, childrenNodes, thickness)
@@ -681,6 +677,7 @@ export function generateExtrudedWall(
 
   // Create wall brush from geometry
   // Pre-compute BVH with new API to avoid deprecation warning
+  ensureRenderableGeometryAttributes(geometry)
   computeGeometryBoundsTree(geometry)
 
   const wallBrush = new Brush(geometry)
@@ -689,8 +686,9 @@ export function generateExtrudedWall(
   // Subtract each cutout from the wall
   let resultBrush = wallBrush
   for (const cutoutBrush of cutoutBrushes) {
-    cutoutBrush.updateMatrixWorld()
+    prepareBrushForCSG(cutoutBrush)
     const newResult = csgEvaluator.evaluate(resultBrush, cutoutBrush, SUBTRACTION)
+    prepareBrushForCSG(newResult)
     if (resultBrush !== wallBrush) {
       csgGeometry(resultBrush).dispose()
     }
@@ -706,7 +704,7 @@ export function generateExtrudedWall(
   const resultGeometry = csgGeometry(resultBrush)
   resultGeometry.computeVertexNormals()
   assignWallMaterialGroups(resultGeometry, wallNode, boundaryEdges)
-  ensureUv2Attribute(resultGeometry)
+  ensureRenderableGeometryAttributes(resultGeometry)
 
   return resultGeometry
 }
@@ -799,189 +797,23 @@ function collectCutoutBrushes(
   return brushes
 }
 
-type ShapedOpeningNode = DoorNode | WindowNode
-type CornerRadii = {
-  topLeft: number
-  topRight: number
-  bottomRight: number
-  bottomLeft: number
-}
-
-function createShapedOpeningCutoutBrush(opening: ShapedOpeningNode, wallThickness: number): Brush {
-  const shape = createShapedOpeningCutoutShape(opening)
-  const depth = wallThickness * 2
-  const bevelSize =
-    opening.openingShape === 'rounded'
-      ? Math.min(
-          Math.max(opening.openingRevealRadius ?? 0.025, 0),
-          Math.max(wallThickness * 0.45, 0.001),
-          Math.max((opening.cornerRadius ?? 0.15) * 0.45, 0.001),
-        )
-      : 0
-  const geometry = new THREE.ExtrudeGeometry(shape, {
-    depth,
-    bevelEnabled: bevelSize > 0,
-    bevelSegments: bevelSize > 0 ? 8 : 0,
-    bevelSize,
-    bevelThickness: bevelSize,
-    curveSegments: 24,
-  })
-
-  geometry.translate(0, 0, -depth / 2)
+function createShapedOpeningCutoutBrush(
+  opening: DoorNode | WindowNode,
+  wallThickness: number,
+): Brush {
+  const halfWidth = opening.width / 2
+  const geometry = buildOpeningCutoutGeometry(
+    opening,
+    {
+      left: opening.position[0] - halfWidth,
+      right: opening.position[0] + halfWidth,
+      bottom: opening.position[1] - opening.height / 2,
+      top: opening.position[1] + opening.height / 2,
+    },
+    wallThickness * 2,
+    wallThickness,
+  )
   computeGeometryBoundsTree(geometry)
 
   return new Brush(geometry)
 }
-
-function createShapedOpeningCutoutShape(opening: ShapedOpeningNode): THREE.Shape {
-  const halfWidth = opening.width / 2
-  const bottom = opening.position[1] - opening.height / 2
-  const top = opening.position[1] + opening.height / 2
-  const centerX = opening.position[0]
-  const left = centerX - halfWidth
-  const right = centerX + halfWidth
-  const width = Math.max(opening.width, 1e-6)
-  const height = Math.max(opening.height, 1e-6)
-  const shape = new THREE.Shape()
-
-  if (opening.openingShape === 'arch') {
-    const archHeight = Math.min(Math.max(opening.archHeight ?? width / 2, 0.01), height)
-    const springY = top - archHeight
-    const segments = 32
-
-    shape.moveTo(left, bottom)
-    shape.lineTo(right, bottom)
-    shape.lineTo(right, springY)
-    for (let index = 1; index <= segments; index += 1) {
-      const x = right + (left - right) * (index / segments)
-      const normalizedX = Math.min(Math.abs((x - centerX) / halfWidth), 1)
-      const y = springY + archHeight * Math.sqrt(Math.max(1 - normalizedX * normalizedX, 0))
-      shape.lineTo(x, y)
-    }
-    shape.lineTo(left, bottom)
-    shape.closePath()
-    return shape
-  }
-
-  if (opening.openingShape === 'rounded') {
-    const radii = getRoundedOpeningRadii(opening, width, height)
-    applyRoundedOpeningShape(shape, left, right, bottom, top, radii)
-    return shape
-  }
-
-  shape.moveTo(left, bottom)
-  shape.lineTo(right, bottom)
-  shape.lineTo(right, top)
-  shape.lineTo(left, top)
-  shape.closePath()
-  return shape
-}
-
-function getRoundedOpeningRadii(
-  opening: ShapedOpeningNode,
-  width: number,
-  height: number,
-): CornerRadii {
-  if (opening.type !== 'window') {
-    if (opening.openingRadiusMode === 'individual') {
-      const [topLeft = 0, topRight = 0] = opening.openingTopRadii ?? [0.15, 0.15]
-
-      return normalizeCornerRadii(
-        {
-          topLeft: Math.max(topLeft, 0),
-          topRight: Math.max(topRight, 0),
-          bottomRight: 0,
-          bottomLeft: 0,
-        },
-        width,
-        height,
-      )
-    }
-
-    const maxRadius = Math.min(width / 2, height)
-    const radius = Math.min(Math.max(opening.cornerRadius ?? 0.15, 0), maxRadius)
-    return { topLeft: radius, topRight: radius, bottomRight: 0, bottomLeft: 0 }
-  }
-
-  if (opening.openingRadiusMode === 'individual') {
-    const [topLeft = 0, topRight = 0, bottomRight = 0, bottomLeft = 0] =
-      opening.openingCornerRadii ?? [0.15, 0.15, 0.15, 0.15]
-
-    return normalizeCornerRadii(
-      {
-        topLeft: Math.max(topLeft, 0),
-        topRight: Math.max(topRight, 0),
-        bottomRight: Math.max(bottomRight, 0),
-        bottomLeft: Math.max(bottomLeft, 0),
-      },
-      width,
-      height,
-    )
-  }
-
-  const maxRadius = Math.min(width / 2, height / 2)
-  const radius = Math.min(Math.max(opening.cornerRadius ?? 0.15, 0), maxRadius)
-  return { topLeft: radius, topRight: radius, bottomRight: radius, bottomLeft: radius }
-}
-
-function normalizeCornerRadii(radii: CornerRadii, width: number, height: number): CornerRadii {
-  const next = { ...radii }
-  const maxScale = Math.min(
-    1,
-    width / Math.max(next.topLeft + next.topRight, 1e-6),
-    width / Math.max(next.bottomLeft + next.bottomRight, 1e-6),
-    height / Math.max(next.topLeft + next.bottomLeft, 1e-6),
-    height / Math.max(next.topRight + next.bottomRight, 1e-6),
-  )
-
-  if (maxScale < 1) {
-    next.topLeft *= maxScale
-    next.topRight *= maxScale
-    next.bottomRight *= maxScale
-    next.bottomLeft *= maxScale
-  }
-
-  return next
-}
-
-function applyRoundedOpeningShape(
-  shape: THREE.Shape,
-  left: number,
-  right: number,
-  bottom: number,
-  top: number,
-  radii: CornerRadii,
-) {
-  const { topLeft, topRight, bottomRight, bottomLeft } = radii
-
-  shape.moveTo(left + bottomLeft, bottom)
-  shape.lineTo(right - bottomRight, bottom)
-  if (bottomRight > 1e-6) {
-    shape.absarc(right - bottomRight, bottom + bottomRight, bottomRight, -Math.PI / 2, 0, false)
-  } else {
-    shape.lineTo(right, bottom)
-  }
-
-  shape.lineTo(right, top - topRight)
-  if (topRight > 1e-6) {
-    shape.absarc(right - topRight, top - topRight, topRight, 0, Math.PI / 2, false)
-  } else {
-    shape.lineTo(right, top)
-  }
-
-  shape.lineTo(left + topLeft, top)
-  if (topLeft > 1e-6) {
-    shape.absarc(left + topLeft, top - topLeft, topLeft, Math.PI / 2, Math.PI, false)
-  } else {
-    shape.lineTo(left, top)
-  }
-
-  shape.lineTo(left, bottom + bottomLeft)
-  if (bottomLeft > 1e-6) {
-    shape.absarc(left + bottomLeft, bottom + bottomLeft, bottomLeft, Math.PI, Math.PI * 1.5, false)
-  } else {
-    shape.lineTo(left, bottom)
-  }
-
-  shape.closePath()
-}