feat(editor): live floor-stacking, unified handle system, slab-hole editing + interaction polish (#375)

- Live slab-stacking Y previews for all floor-placed kinds (item/shelf/spawn/column/stair) during placement + both move pathways, via a shared core resolver; canonical positions unchanged.
- Unified 3D handle system (one drag pipeline + one visual primitive) with forgiving invisible hit-areas on every handle, kept on EDITOR_LAYER so they don't poison the MRT scene pass.
- Hover + click-to-edit slab holes in 3D (manual hole -> hole editor; stair/elevator hole -> select owner); generic cross-arrow polygon-move grip; normalized handle interaction colors.
- NaN-safe node mutations + non-finite shadow-light bounds guard.
- Built on #373 (level-scoped alignment / registry slab tool); #373 owns X/Z alignment, this owns Y floor-stacking.

packages/core/src/hooks/spatial-grid/floor-placed-elevation.test.ts

@@ -0,0 +1,365 @@
+import { beforeEach, describe, expect, test } from 'bun:test'
+import { z } from 'zod'
+import { nodeRegistry, registerNode } from '../../registry'
+import type { AnyNodeDefinition } from '../../registry/types'
+import type { AnyNode, SlabNode } from '../../schema'
+import { getFloorPlacedElevation, getFloorStackedPosition } from './floor-placed-elevation'
+import { spatialGridManager } from './spatial-grid-manager'
+
+const LEVEL_ID = 'level_test'
+
+function makeDefinition(
+  kind: AnyNode['type'],
+  capabilities: AnyNodeDefinition['capabilities'] = {},
+): AnyNodeDefinition {
+  return {
+    kind,
+    schemaVersion: 1,
+    schema: z.object({ type: z.literal(kind) }) as never,
+    category: 'utility',
+    defaults: () => ({}) as never,
+    capabilities,
+  }
+}
+
+function makeLevel(): AnyNode {
+  return {
+    id: LEVEL_ID,
+    type: 'level',
+    object: 'node',
+    parentId: null,
+    visible: true,
+    metadata: {},
+    children: [],
+    level: 0,
+  } as AnyNode
+}
+
+function makeFloorNode(overrides: Partial<AnyNode> = {}): AnyNode {
+  return {
+    id: 'item_test',
+    type: 'item',
+    object: 'node',
+    parentId: LEVEL_ID,
+    visible: true,
+    metadata: {},
+    children: [],
+    position: [0, 0, 0],
+    rotation: [0, 0, 0],
+    scale: [1, 1, 1],
+    asset: {
+      id: 'asset_test',
+      category: 'test',
+      name: 'Test',
+      thumbnail: '',
+      src: 'asset:test',
+      dimensions: [1, 1, 1],
+      source: 'library',
+    },
+    ...overrides,
+  } as AnyNode
+}
+
+function addSlab(polygon: Array<[number, number]>, elevation: number, id = `slab_${elevation}`) {
+  const slab = {
+    id,
+    type: 'slab',
+    object: 'node',
+    parentId: LEVEL_ID,
+    visible: true,
+    metadata: {},
+    children: [],
+    polygon,
+    holes: [],
+    holeMetadata: [],
+    elevation,
+    autoFromWalls: false,
+  } as SlabNode
+  spatialGridManager.handleNodeCreated(slab as AnyNode, LEVEL_ID)
+}
+
+function nodesFor(...nodes: AnyNode[]): Record<string, AnyNode> {
+  return Object.fromEntries(nodes.map((node) => [node.id, node]))
+}
+
+describe('floor-placed elevation resolver', () => {
+  beforeEach(() => {
+    nodeRegistry._reset()
+    spatialGridManager.clear()
+  })
+
+  test('returns 0 without a floorPlaced capability', () => {
+    registerNode(makeDefinition('item'))
+    addSlab(
+      [
+        [-1, -1],
+        [1, -1],
+        [1, 1],
+        [-1, 1],
+      ],
+      0.4,
+    )
+
+    const level = makeLevel()
+    const node = makeFloorNode()
+
+    expect(
+      getFloorPlacedElevation({
+        node,
+        nodes: nodesFor(level, node),
+        position: [0, 0, 0],
+        rotation: [0, 0, 0],
+      }),
+    ).toBe(0)
+  })
+
+  test('returns 0 when applies returns false', () => {
+    registerNode(
+      makeDefinition('item', {
+        floorPlaced: {
+          footprint: () => ({ dimensions: [1, 1, 1], rotation: [0, 0, 0] }),
+          applies: () => false,
+        },
+      }),
+    )
+    addSlab(
+      [
+        [-1, -1],
+        [1, -1],
+        [1, 1],
+        [-1, 1],
+      ],
+      0.4,
+    )
+
+    const level = makeLevel()
+    const node = makeFloorNode()
+
+    expect(
+      getFloorPlacedElevation({
+        node,
+        nodes: nodesFor(level, node),
+        position: [0, 0, 0],
+        rotation: [0, 0, 0],
+      }),
+    ).toBe(0)
+  })
+
+  test('clamps non-finite slab elevation to 0', () => {
+    registerNode(
+      makeDefinition('item', {
+        floorPlaced: {
+          footprint: () => ({ dimensions: [1, 1, 1], rotation: [0, 0, 0] }),
+        },
+      }),
+    )
+
+    const original = spatialGridManager.getSlabElevationForItem
+    spatialGridManager.getSlabElevationForItem = (() => Number.NaN) as typeof original
+
+    try {
+      const level = makeLevel()
+      const node = makeFloorNode()
+
+      expect(
+        getFloorPlacedElevation({
+          node,
+          nodes: nodesFor(level, node),
+          position: [0, 0, 0],
+          rotation: [0, 0, 0],
+        }),
+      ).toBe(0)
+    } finally {
+      spatialGridManager.getSlabElevationForItem = original
+    }
+  })
+
+  test('returns 0 for a non-level direct parent', () => {
+    registerNode(
+      makeDefinition('item', {
+        floorPlaced: {
+          footprint: () => ({ dimensions: [1, 1, 1], rotation: [0, 0, 0] }),
+        },
+      }),
+    )
+    addSlab(
+      [
+        [-1, -1],
+        [1, -1],
+        [1, 1],
+        [-1, 1],
+      ],
+      0.4,
+    )
+
+    const level = makeLevel()
+    const shelf = {
+      id: 'shelf_test',
+      type: 'shelf',
+      parentId: LEVEL_ID,
+    } as unknown as AnyNode
+    const node = makeFloorNode({ parentId: shelf.id })
+
+    expect(
+      getFloorPlacedElevation({
+        node,
+        nodes: nodesFor(level, shelf, node),
+        position: [0, 0, 0],
+        rotation: [0, 0, 0],
+      }),
+    ).toBe(0)
+  })
+
+  test('returns 0 when the declared parent is missing', () => {
+    registerNode(
+      makeDefinition('item', {
+        floorPlaced: {
+          footprint: () => ({ dimensions: [1, 1, 1], rotation: [0, 0, 0] }),
+        },
+      }),
+    )
+    addSlab(
+      [
+        [-1, -1],
+        [1, -1],
+        [1, 1],
+        [-1, 1],
+      ],
+      0.4,
+    )
+
+    const node = makeFloorNode({ parentId: 'missing_level' })
+
+    expect(
+      getFloorPlacedElevation({
+        node,
+        nodes: nodesFor(node),
+        position: [0, 0, 0],
+        rotation: [0, 0, 0],
+        levelId: LEVEL_ID,
+      }),
+    ).toBe(0)
+  })
+
+  test('uses the pending rotated footprint', () => {
+    registerNode(
+      makeDefinition('item', {
+        floorPlaced: {
+          footprint: (node) => ({
+            dimensions: [4, 1, 1],
+            rotation: (node as { rotation: [number, number, number] }).rotation,
+          }),
+        },
+      }),
+    )
+    addSlab(
+      [
+        [-0.2, 1.2],
+        [0.2, 1.2],
+        [0.2, 1.8],
+        [-0.2, 1.8],
+      ],
+      0.45,
+    )
+
+    const level = makeLevel()
+    const node = makeFloorNode()
+
+    expect(
+      getFloorPlacedElevation({
+        node,
+        nodes: nodesFor(level, node),
+        position: [0, 0, 0],
+        rotation: [0, Math.PI / 2, 0],
+      }),
+    ).toBeCloseTo(0.45)
+  })
+
+  test('returns slab overlap elevation and stacks Y onto canonical position', () => {
+    registerNode(
+      makeDefinition('item', {
+        floorPlaced: {
+          footprint: (node) => ({
+            dimensions: [1, 1, 1],
+            rotation: (node as { rotation: [number, number, number] }).rotation,
+          }),
+        },
+      }),
+    )
+    addSlab(
+      [
+        [-1, -1],
+        [1, -1],
+        [1, 1],
+        [-1, 1],
+      ],
+      0.35,
+    )
+
+    const level = makeLevel()
+    const node = makeFloorNode()
+
+    expect(
+      getFloorPlacedElevation({
+        node,
+        nodes: nodesFor(level, node),
+        position: [0, 0.1, 0],
+        rotation: [0, 0, 0],
+      }),
+    ).toBeCloseTo(0.35)
+    const stacked = getFloorStackedPosition({
+      node,
+      nodes: nodesFor(level, node),
+      position: [0, 0.1, 0],
+      rotation: [0, 0, 0],
+    })
+    expect(stacked[0]).toBe(0)
+    expect(stacked[1]).toBeCloseTo(0.45)
+    expect(stacked[2]).toBe(0)
+  })
+
+  test('takes the max elevation across composite footprints', () => {
+    registerNode(
+      makeDefinition('item', {
+        floorPlaced: {
+          footprints: () => [
+            { position: [0, 0, 0], dimensions: [1, 1, 1], rotation: [0, 0, 0] },
+            { position: [3, 0, 0], dimensions: [1, 1, 1], rotation: [0, 0, 0] },
+          ],
+        },
+      }),
+    )
+    addSlab(
+      [
+        [-1, -1],
+        [1, -1],
+        [1, 1],
+        [-1, 1],
+      ],
+      0.2,
+      'slab_low',
+    )
+    addSlab(
+      [
+        [2.5, -0.5],
+        [3.5, -0.5],
+        [3.5, 0.5],
+        [2.5, 0.5],
+      ],
+      0.8,
+      'slab_high',
+    )
+
+    const level = makeLevel()
+    const node = makeFloorNode()
+
+    expect(
+      getFloorPlacedElevation({
+        node,
+        nodes: nodesFor(level, node),
+        position: [0, 0, 0],
+        rotation: [0, 0, 0],
+      }),
+    ).toBeCloseTo(0.8)
+  })
+})

packages/core/src/hooks/spatial-grid/floor-placed-elevation.ts

@@ -0,0 +1,93 @@
+import { nodeRegistry } from '../../registry'
+import type {
+  FloorPlacedConfig,
+  FloorPlacedFootprint,
+  FloorPlacedFootprintContext,
+  FloorPlacedFootprintsResolver,
+} from '../../registry/types'
+import type { AnyNode, AnyNodeId } from '../../schema'
+import { spatialGridManager } from './spatial-grid-manager'
+
+export type FloorPlacedElevationArgs = {
+  node: AnyNode
+  nodes: Record<string, AnyNode>
+  position: [number, number, number]
+  rotation?: unknown
+  levelId?: string | null
+}
+
+function finiteSlabElevation(elevation: number): number {
+  return Number.isFinite(elevation) ? elevation : 0
+}
+
+function withPositionAndRotation({
+  node,
+  position,
+  rotation,
+}: Pick<FloorPlacedElevationArgs, 'node' | 'position' | 'rotation'>): AnyNode {
+  return {
+    ...(node as Record<string, unknown>),
+    position,
+    ...(rotation !== undefined ? { rotation } : {}),
+  } as AnyNode
+}
+
+export function getFloorPlacedFootprints(
+  floorPlaced: FloorPlacedConfig,
+  node: AnyNode,
+  ctx?: FloorPlacedFootprintContext,
+): FloorPlacedFootprint[] {
+  const rawFootprints = floorPlaced.footprints?.(node, ctx)
+  if (rawFootprints) return [...rawFootprints]
+
+  const footprint = floorPlaced.footprint?.(node, ctx)
+  return footprint ? [footprint] : []
+}
+
+export function getFloorPlacedElevation({
+  node,
+  nodes,
+  position,
+  rotation,
+  levelId,
+}: FloorPlacedElevationArgs): number {
+  const floorPlaced = nodeRegistry.get(node.type)?.capabilities?.floorPlaced
+  if (!floorPlaced) return 0
+
+  const effectiveNode = withPositionAndRotation({ node, position, rotation })
+  if (floorPlaced.applies && !floorPlaced.applies(effectiveNode)) return 0
+
+  const parentId = (effectiveNode as { parentId?: AnyNodeId | null }).parentId ?? null
+  const parent = parentId ? nodes[parentId] : null
+  if (parentId && !parent) return 0
+  if (parent && parent.type !== 'level') return 0
+  if (!parent && !levelId) return 0
+
+  const resolvedLevelId = parent?.type === 'level' ? parent.id : levelId
+  if (!resolvedLevelId) return 0
+
+  let maxElevation = Number.NEGATIVE_INFINITY
+  for (const footprint of getFloorPlacedFootprints(floorPlaced, effectiveNode, { nodes })) {
+    const footprintPosition = footprint.position ?? position
+    const elevation = finiteSlabElevation(
+      spatialGridManager.getSlabElevationForItem(
+        resolvedLevelId,
+        footprintPosition,
+        footprint.dimensions,
+        footprint.rotation,
+      ),
+    )
+    if (elevation > maxElevation) {
+      maxElevation = elevation
+    }
+  }
+
+  return maxElevation === Number.NEGATIVE_INFINITY ? 0 : maxElevation
+}
+
+export function getFloorStackedPosition(args: FloorPlacedElevationArgs): [number, number, number] {
+  const [x, y, z] = args.position
+  return [x, y + getFloorPlacedElevation(args), z]
+}
+
+export type { FloorPlacedFootprint, FloorPlacedFootprintContext, FloorPlacedFootprintsResolver }

packages/core/src/hooks/spatial-grid/spatial-grid-sync.ts

@@ -1,6 +1,7 @@
 import { nodeRegistry } from '../../registry'
 import type { AnyNode, AnyNodeId, SlabNode, WallNode } from '../../schema'
 import useScene from '../../store/use-scene'
+import { getFloorPlacedFootprints } from './floor-placed-elevation'
 import {
   itemOverlapsPolygon,
   spatialGridManager,
@@ -152,7 +153,7 @@ function arraysEqual(a: number[], b: number[]): boolean {
 }
 
 /**
- * Mark all floor items, walls, and stairs that may be affected by a slab change as dirty.
+ * Mark all floor items and walls that may be affected by a slab change as dirty.
  */
 function markNodesOverlappingSlab(
   slab: SlabNode,
@@ -181,12 +182,6 @@ function markNodesOverlappingSlab(
       }
       continue
     }
-    if (node.type === 'stair') {
-      if (resolveLevelId(node, nodes) !== slabLevelId) continue
-      markDirty(node.id)
-      continue
-    }
-
     // Generic floor-placed sweep: any registry kind that opts in via
     // `capabilities.floorPlaced` (item / shelf / column / spawn / …)
     // re-elevates through `<FloorElevationSystem>` when a slab below
@@ -196,12 +191,25 @@ function markNodesOverlappingSlab(
     const floorPlaced = def?.capabilities?.floorPlaced
     if (!floorPlaced) continue
     if (floorPlaced.applies && !floorPlaced.applies(node)) continue
+    const parentId = node.parentId as AnyNodeId | null
+    const parent = parentId ? nodes[parentId] : null
+    if (parent && parent.type !== 'level') continue
     if (resolveLevelId(node, nodes) !== slabLevelId) continue
     const position = (node as { position?: [number, number, number] }).position
     if (!position) continue
-    const { dimensions, rotation } = floorPlaced.footprint(node)
-    if (itemOverlapsPolygon(position, dimensions, rotation, slab.polygon, 0.01)) {
+    for (const footprint of getFloorPlacedFootprints(floorPlaced, node, { nodes })) {
+      if (
+        itemOverlapsPolygon(
+          footprint.position ?? position,
+          footprint.dimensions,
+          footprint.rotation,
+          slab.polygon,
+          0.01,
+        )
+      ) {
         markDirty(node.id)
+        break
+      }
     }
   }
 }

packages/core/src/index.ts

@@ -38,6 +38,12 @@ export {
   sceneRegistry,
   useRegistry,
 } from './hooks/scene-registry/scene-registry'
+export {
+  type FloorPlacedElevationArgs,
+  getFloorPlacedElevation,
+  getFloorPlacedFootprints,
+  getFloorStackedPosition,
+} from './hooks/spatial-grid/floor-placed-elevation'
 export { pointInPolygon, spatialGridManager } from './hooks/spatial-grid/spatial-grid-manager'
 export {
   initSpatialGridSync,
@@ -79,6 +85,12 @@ export {
   type MaterialCategory,
   toLibraryMaterialRef,
 } from './material-library'
+export type {
+  FloorPlacedFootprint,
+  FloorPlacedFootprintContext,
+  FloorPlacedFootprintResolver,
+  FloorPlacedFootprintsResolver,
+} from './registry'
 export * from './registry'
 export * from './schema'
 export * from './services'

packages/core/src/registry/handles.ts

@@ -346,8 +346,10 @@ export type TranslateHandle<N = any> = {
    * `[alongX, alongOther]` — `alongOther` is Z for the 'horizontal' plane and
    * Y for 'node-normal'. Used to align the node's edges to the grid (rotation-
    * aware: swap the pair at 90°). Omit / return null for free movement.
+   * `sceneApi` is supplied for composite nodes whose footprint depends on
+   * children, such as straight stairs.
    */
-  snapExtents?: (node: N) => readonly [number, number] | null
+  snapExtents?: (node: N, sceneApi: SceneApi) => readonly [number, number] | null
   portal?: HandlePortal
 }
 

packages/core/src/registry/index.ts

@@ -57,6 +57,11 @@ export type {
   CuttableConfig,
   DragAction,
   EditorCtx,
+  FloorPlacedConfig,
+  FloorPlacedFootprint,
+  FloorPlacedFootprintContext,
+  FloorPlacedFootprintResolver,
+  FloorPlacedFootprintsResolver,
   FloorplanAffordance,
   FloorplanAffordanceModifiers,
   FloorplanAffordancePoint,

packages/core/src/registry/types.ts

@@ -1235,20 +1235,40 @@ export type SelectableConfig = {
   override?: (ctx: CapabilityCtx) => SelectableConfig | null
 }
 
+export type FloorPlacedFootprint = {
+  dimensions: [number, number, number]
+  rotation: [number, number, number]
+  position?: [number, number, number]
+}
+
+export type FloorPlacedFootprintContext = {
+  nodes: Readonly<Record<AnyNodeId, AnyNode>>
+}
+
+export type FloorPlacedFootprintResolver = (
+  node: AnyNode,
+  ctx?: FloorPlacedFootprintContext,
+) => FloorPlacedFootprint
+
+export type FloorPlacedFootprintsResolver = (
+  node: AnyNode,
+  ctx?: FloorPlacedFootprintContext,
+) => readonly FloorPlacedFootprint[]
+
 /**
  * Floor-placed kinds rest directly on a level and need their Y lifted by
  * any slab the footprint overlaps. The generic `<FloorElevationSystem>`
  * computes `slabElevation + node.position[1]` and writes it onto the
- * registered mesh on every dirty mark. `footprint` returns the world-space
- * footprint the spatial-grid manager uses to find overlapping slabs;
+ * registered mesh on every dirty mark. `footprint` returns the default
+ * world-space footprint the spatial-grid manager uses to find overlapping
+ * slabs; `footprints` lets composite kinds expose multiple footprint
+ * segments, with the canonical resolver taking the max slab elevation;
  * `applies` is an optional predicate to skip nodes that share a kind but
  * are mounted off-floor (items attached to a wall / ceiling).
  */
 export type FloorPlacedConfig = {
-  footprint: (node: AnyNode) => {
-    dimensions: [number, number, number]
-    rotation: [number, number, number]
-  }
+  footprint?: FloorPlacedFootprintResolver
+  footprints?: FloorPlacedFootprintsResolver
   applies?: (node: AnyNode) => boolean
 }
 

packages/core/src/services/alignment-anchors.ts

@@ -74,7 +74,10 @@ function floorFootprint(
 ): { dimensions: [number, number, number]; rotation: [number, number, number] } | null {
   const capabilities = nodeRegistry.get(node.type)?.capabilities
   const floorPlaced = capabilities?.floorPlaced
-  if (floorPlaced) {
+  // `footprint` is optional now that floor-placed kinds may instead declare
+  // composite `footprints` (e.g. stairs); those have no single centred box
+  // here, so fall through to `alignmentFootprint`.
+  if (floorPlaced?.footprint) {
     if (floorPlaced.applies && !floorPlaced.applies(node)) return null
     return floorPlaced.footprint(node)
   }

packages/core/src/store/actions/node-actions.ts

@@ -1,6 +1,7 @@
 import {
   type AnyNode,
   type AnyNodeId,
+  AnyNode as AnyNodeSchema,
   getEffectiveWallSurfaceMaterial,
   getWallSurfaceMaterialSignature,
   type WallNode,
@@ -22,6 +23,478 @@ type WallMergePlan = {
   attachmentUpdates: WallAttachmentUpdate[]
 }
 
+type ZodCheckLike = {
+  _zod?: {
+    def?: {
+      check?: string
+      value?: unknown
+      inclusive?: boolean
+      format?: string
+    }
+  }
+}
+
+type ZodSchemaDefLike = {
+  type?: string
+  innerType?: ZodSchemaLike
+  shape?: Record<string, ZodSchemaLike>
+  options?: readonly ZodSchemaLike[]
+  items?: readonly ZodSchemaLike[]
+  rest?: ZodSchemaLike | null
+  element?: ZodSchemaLike
+  checks?: readonly ZodCheckLike[]
+  defaultValue?: unknown
+  values?: readonly unknown[]
+  entries?: Record<string, unknown>
+}
+
+type ZodSchemaLike = {
+  _zod?: {
+    def?: ZodSchemaDefLike
+    bag?: {
+      minimum?: number
+      maximum?: number
+      exclusiveMinimum?: number
+      exclusiveMaximum?: number
+    }
+    values?: Set<unknown>
+  }
+  def?: ZodSchemaDefLike
+  shape?: Record<string, ZodSchemaLike>
+  minValue?: number | null
+  maxValue?: number | null
+}
+
+type NumericLimit = {
+  value: number
+  inclusive: boolean
+}
+
+type NumericConstraints = {
+  min?: NumericLimit
+  max?: NumericLimit
+  integer: boolean
+}
+
+type NumericSanitizeIssue = {
+  path: PropertyKey[]
+  from: number
+  to?: number
+  action: 'clamped' | 'dropped' | 'rounded'
+}
+
+type NumericSanitizeResult = {
+  value: unknown
+  issues: NumericSanitizeIssue[]
+  omit?: boolean
+}
+
+const NUMBER_FORMAT_BOUNDS: Record<string, [number, number] | undefined> = {
+  safeint: [Number.MIN_SAFE_INTEGER, Number.MAX_SAFE_INTEGER],
+  int32: [-2147483648, 2147483647],
+  uint32: [0, 4294967295],
+  float32: [-3.4028234663852886e38, 3.4028234663852886e38],
+}
+
+const INTEGER_NUMBER_FORMATS = new Set(['safeint', 'int32', 'uint32'])
+
+function getSchemaDef(schema: ZodSchemaLike | null | undefined): ZodSchemaDefLike | undefined {
+  return schema?._zod?.def ?? schema?.def
+}
+
+function getSchemaDefault(schema: ZodSchemaLike): unknown {
+  const def = getSchemaDef(schema)
+  if (!(def?.type === 'default' || def?.type === 'prefault')) return undefined
+  return def.defaultValue
+}
+
+function unwrapSchema(schema: ZodSchemaLike | null | undefined): ZodSchemaLike | null {
+  let current = schema ?? null
+  while (current) {
+    const def = getSchemaDef(current)
+    if (
+      !(
+        def?.type === 'default' ||
+        def?.type === 'prefault' ||
+        def?.type === 'optional' ||
+        def?.type === 'nullable' ||
+        def?.type === 'catch' ||
+        def?.type === 'readonly' ||
+        def?.type === 'nonoptional'
+      )
+    ) {
+      return current
+    }
+    current = def.innerType ?? null
+  }
+
+  return null
+}
+
+function getObjectShape(schema: ZodSchemaLike | null | undefined) {
+  const unwrapped = unwrapSchema(schema)
+  const def = getSchemaDef(unwrapped)
+  if (def?.type !== 'object') return null
+
+  return unwrapped?.shape ?? def.shape ?? null
+}
+
+function schemaAllowsValue(schema: ZodSchemaLike | null | undefined, value: unknown): boolean {
+  const unwrapped = unwrapSchema(schema)
+  if (!unwrapped) return false
+
+  const def = getSchemaDef(unwrapped)
+  if (unwrapped._zod?.values?.has(value)) return true
+  if (Array.isArray(def?.values) && def.values.includes(value)) return true
+  if (def?.entries && Object.values(def.entries).includes(value)) return true
+
+  return false
+}
+
+function getNodeSchemaForType(type: unknown): ZodSchemaLike | null {
+  const schema = AnyNodeSchema as unknown as ZodSchemaLike
+  const options = getSchemaDef(schema)?.options
+  if (!options) return null
+
+  for (const option of options) {
+    const shape = getObjectShape(option)
+    if (shape?.type && schemaAllowsValue(shape.type, type)) {
+      return option
+    }
+  }
+
+  return null
+}
+
+function applyLowerLimit(current: NumericLimit | undefined, candidate: NumericLimit): NumericLimit {
+  if (!current) return candidate
+  if (candidate.value > current.value) return candidate
+  if (candidate.value === current.value && !candidate.inclusive) return candidate
+  return current
+}
+
+function applyUpperLimit(current: NumericLimit | undefined, candidate: NumericLimit): NumericLimit {
+  if (!current) return candidate
+  if (candidate.value < current.value) return candidate
+  if (candidate.value === current.value && !candidate.inclusive) return candidate
+  return current
+}
+
+function getNumberConstraints(schema: ZodSchemaLike): NumericConstraints {
+  const unwrapped = unwrapSchema(schema) ?? schema
+  const def = getSchemaDef(unwrapped)
+  const constraints: NumericConstraints = { integer: false }
+
+  const minValue = unwrapped.minValue
+  if (typeof minValue === 'number') {
+    constraints.min = applyLowerLimit(constraints.min, { value: minValue, inclusive: true })
+  }
+
+  const maxValue = unwrapped.maxValue
+  if (typeof maxValue === 'number') {
+    constraints.max = applyUpperLimit(constraints.max, { value: maxValue, inclusive: true })
+  }
+
+  for (const check of def?.checks ?? []) {
+    const checkDef = check._zod?.def
+    if (!checkDef) continue
+
+    if (checkDef.check === 'greater_than' && typeof checkDef.value === 'number') {
+      constraints.min = applyLowerLimit(constraints.min, {
+        value: checkDef.value,
+        inclusive: checkDef.inclusive !== false,
+      })
+    } else if (checkDef.check === 'less_than' && typeof checkDef.value === 'number') {
+      constraints.max = applyUpperLimit(constraints.max, {
+        value: checkDef.value,
+        inclusive: checkDef.inclusive !== false,
+      })
+    } else if (checkDef.check === 'number_format' && checkDef.format) {
+      constraints.integer ||= INTEGER_NUMBER_FORMATS.has(checkDef.format)
+      const bounds = NUMBER_FORMAT_BOUNDS[checkDef.format]
+      if (bounds) {
+        constraints.min = applyLowerLimit(constraints.min, {
+          value: bounds[0],
+          inclusive: true,
+        })
+        constraints.max = applyUpperLimit(constraints.max, {
+          value: bounds[1],
+          inclusive: true,
+        })
+      }
+    }
+  }
+
+  const bag = unwrapped._zod?.bag
+  if (typeof bag?.minimum === 'number') {
+    constraints.min = applyLowerLimit(constraints.min, { value: bag.minimum, inclusive: true })
+  }
+  if (typeof bag?.exclusiveMinimum === 'number') {
+    constraints.min = applyLowerLimit(constraints.min, {
+      value: bag.exclusiveMinimum,
+      inclusive: false,
+    })
+  }
+  if (typeof bag?.maximum === 'number') {
+    constraints.max = applyUpperLimit(constraints.max, { value: bag.maximum, inclusive: true })
+  }
+  if (typeof bag?.exclusiveMaximum === 'number') {
+    constraints.max = applyUpperLimit(constraints.max, {
+      value: bag.exclusiveMaximum,
+      inclusive: false,
+    })
+  }
+
+  return constraints
+}
+
+function nextAbove(value: number) {
+  return value === 0 ? Number.EPSILON : value + Math.abs(value) * Number.EPSILON
+}
+
+function nextBelow(value: number) {
+  return value === 0 ? -Number.EPSILON : value - Math.abs(value) * Number.EPSILON
+}
+
+function clampNumber(value: number, constraints: NumericConstraints) {
+  let next = value
+  let rounded = false
+  let clamped = false
+
+  if (constraints.integer && !Number.isInteger(next)) {
+    next = Math.round(next)
+    rounded = true
+  }
+
+  if (constraints.min) {
+    const min = constraints.min.inclusive ? constraints.min.value : nextAbove(constraints.min.value)
+    if (next < min) {
+      next = min
+      clamped = true
+    }
+  }
+
+  if (constraints.max) {
+    const max = constraints.max.inclusive ? constraints.max.value : nextBelow(constraints.max.value)
+    if (next > max) {
+      next = max
+      clamped = true
+    }
+  }
+
+  return {
+    value: next,
+    action: clamped ? 'clamped' : rounded ? 'rounded' : undefined,
+  } satisfies { value: number; action?: NumericSanitizeIssue['action'] }
+}
+
+function getFiniteFallbackNumber(fallback: unknown, constraints: NumericConstraints) {
+  if (typeof fallback !== 'number' || !Number.isFinite(fallback)) return undefined
+  return clampNumber(fallback, constraints).value
+}
+
+function sanitizeNumber(
+  schema: ZodSchemaLike | null,
+  value: number,
+  fallback: unknown,
+  path: PropertyKey[],
+): NumericSanitizeResult {
+  const constraints = schema ? getNumberConstraints(schema) : { integer: false }
+
+  if (!Number.isFinite(value)) {
+    const replacement = getFiniteFallbackNumber(fallback, constraints)
+    if (replacement === undefined) {
+      return {
+        value,
+        omit: true,
+        issues: [{ path, from: value, action: 'dropped' }],
+      }
+    }
+
+    return {
+      value: replacement,
+      issues: [{ path, from: value, to: replacement, action: 'dropped' }],
+    }
+  }
+
+  const clamped = clampNumber(value, constraints)
+  if (!Object.is(clamped.value, value)) {
+    return {
+      value: clamped.value,
+      issues: [
+        {
+          path,
+          from: value,
+          to: clamped.value,
+          action: clamped.action ?? 'clamped',
+        },
+      ],
+    }
+  }
+
+  return { value, issues: [] }
+}
+
+function sanitizeNumericValue(
+  schema: ZodSchemaLike | null,
+  value: unknown,
+  fallback: unknown,
+  path: PropertyKey[],
+): NumericSanitizeResult {
+  const defaultFallback = schema ? getSchemaDefault(schema) : undefined
+  const effectiveFallback = fallback === undefined ? defaultFallback : fallback
+  const unwrapped = unwrapSchema(schema)
+  const def = getSchemaDef(unwrapped)
+
+  if (def?.type === 'number') {
+    if (typeof value !== 'number') return { value, issues: [] }
+    return sanitizeNumber(unwrapped, value, effectiveFallback, path)
+  }
+
+  if (typeof value === 'number') {
+    return sanitizeNumber(null, value, effectiveFallback, path)
+  }
+
+  if (def?.type === 'tuple' && Array.isArray(value)) {
+    const fallbackItems = Array.isArray(effectiveFallback) ? effectiveFallback : []
+    const next = [...value]
+    const issues: NumericSanitizeIssue[] = []
+
+    for (let index = 0; index < next.length; index += 1) {
+      const itemSchema = def.items?.[index] ?? def.rest ?? null
+      const child = sanitizeNumericValue(itemSchema, next[index], fallbackItems[index], [
+        ...path,
+        index,
+      ])
+      issues.push(...child.issues)
+
+      if (child.omit) {
+        return { value, omit: true, issues }
+      }
+
+      next[index] = child.value
+    }
+
+    return { value: issues.length > 0 ? next : value, issues }
+  }
+
+  if (def?.type === 'array' && Array.isArray(value)) {
+    const fallbackItems = Array.isArray(effectiveFallback) ? effectiveFallback : []
+    const next: unknown[] = []
+    const issues: NumericSanitizeIssue[] = []
+    let omitted = false
+
+    for (let index = 0; index < value.length; index += 1) {
+      const child = sanitizeNumericValue(def.element ?? null, value[index], fallbackItems[index], [
+        ...path,
+        index,
+      ])
+      issues.push(...child.issues)
+      if (child.omit) {
+        omitted = true
+        continue
+      }
+      next.push(child.value)
+    }
+
+    return { value: issues.length > 0 || omitted ? next : value, issues }
+  }
+
+  if (value && typeof value === 'object' && !Array.isArray(value)) {
+    const shape = def?.type === 'object' ? (unwrapped?.shape ?? def.shape ?? {}) : {}
+    const fallbackObject =
+      effectiveFallback &&
+      typeof effectiveFallback === 'object' &&
+      !Array.isArray(effectiveFallback)
+        ? (effectiveFallback as Record<string, unknown>)
+        : {}
+    const input = value as Record<string, unknown>
+    const next: Record<string, unknown> = { ...input }
+    const issues: NumericSanitizeIssue[] = []
+
+    for (const key of Object.keys(input)) {
+      const child = sanitizeNumericValue(shape[key] ?? null, input[key], fallbackObject[key], [
+        ...path,
+        key,
+      ])
+      issues.push(...child.issues)
+
+      if (child.omit) {
+        delete next[key]
+      } else {
+        next[key] = child.value
+      }
+    }
+
+    return { value: issues.length > 0 ? next : value, issues }
+  }
+
+  return { value, issues: [] }
+}
+
+function formatNumericValue(value: number) {
+  if (Number.isNaN(value)) return 'NaN'
+  if (value === Infinity) return 'Infinity'
+  if (value === -Infinity) return '-Infinity'
+  return String(value)
+}
+
+function numericSanitizeIssuesToMessage(issues: NumericSanitizeIssue[]): string {
+  return issues
+    .map((issue) => {
+      const path = issue.path.map(String).join('.') || '<root>'
+      const to = issue.to === undefined ? '' : ` -> ${formatNumericValue(issue.to)}`
+      return `${path}: ${formatNumericValue(issue.from)} ${issue.action}${to}`
+    })
+    .join('; ')
+}
+
+function warnSanitizedNodeMutation(
+  mutation: 'create' | 'update',
+  nodeId: AnyNodeId,
+  issues: NumericSanitizeIssue[],
+) {
+  console.warn(
+    `[Scene] Sanitized invalid numeric node ${mutation}`,
+    nodeId,
+    numericSanitizeIssuesToMessage(issues),
+  )
+}
+
+function parseCreatedNode(node: AnyNode, parentId: AnyNodeId | null): AnyNode {
+  const candidate = { ...node, parentId }
+  const parsed = AnyNodeSchema.safeParse(candidate)
+  if (parsed.success) return parsed.data
+
+  const schema = getNodeSchemaForType(candidate.type)
+  const sanitized = sanitizeNumericValue(schema, candidate, undefined, [])
+
+  if (sanitized.issues.length === 0) {
+    return candidate as AnyNode
+  }
+
+  warnSanitizedNodeMutation('create', node.id, sanitized.issues)
+
+  return sanitized.value as AnyNode
+}
+
+function parseUpdatedNode(currentNode: AnyNode, data: Partial<AnyNode>): AnyNode {
+  const candidate = { ...currentNode, ...data }
+  const parsed = AnyNodeSchema.safeParse(candidate)
+  if (parsed.success) return parsed.data
+
+  const schema = getNodeSchemaForType(candidate.type)
+  const sanitized = sanitizeNumericValue(schema, data, currentNode, [])
+
+  if (sanitized.issues.length === 0) {
+    return candidate as AnyNode
+  }
+
+  warnSanitizedNodeMutation('update', currentNode.id, sanitized.issues)
+
+  return { ...currentNode, ...(sanitized.value as Partial<AnyNode>) } as AnyNode
+}
+
 // Track pending RAF for updateNodesAction to prevent multiple queued callbacks
 let pendingRafId: number | null = null
 let pendingUpdates: Set<AnyNodeId> = new Set()
@@ -245,11 +718,7 @@ export const createNodesAction = (
     for (const { node, parentId } of ops) {
       const effectiveParentId = parentId ?? (node.parentId as AnyNodeId | null) ?? null
 
-      // 1. Assign parentId to the child (Safe because BaseNode has parentId)
-      const newNode = {
-        ...node,
-        parentId: effectiveParentId,
-      }
+      const newNode = parseCreatedNode(node, effectiveParentId)
 
       nextNodes[newNode.id] = newNode
 
@@ -313,6 +782,7 @@ export const applyNodeChangesAction = (
     for (const { id, data } of updateOps) {
       const currentNode = nextNodes[id]
       if (!currentNode) continue
+      const updatedNode = parseUpdatedNode(currentNode, data)
 
       if (data.parentId !== undefined && data.parentId !== currentNode.parentId) {
         const oldParentId = currentNode.parentId as AnyNodeId | null
@@ -336,16 +806,13 @@ export const applyNodeChangesAction = (
         }
       }
 
-      nextNodes[id] = { ...currentNode, ...data } as AnyNode
+      nextNodes[id] = updatedNode
       nodesToMarkDirty.add(id)
     }
 
     for (const { node, parentId } of createOps) {
       const effectiveParentId = parentId ?? (node.parentId as AnyNodeId | null) ?? null
-      const newNode = {
-        ...node,
-        parentId: effectiveParentId,
-      } as AnyNode
+      const newNode = parseCreatedNode(node, effectiveParentId)
 
       nextNodes[newNode.id as AnyNodeId] = newNode
       nodesToMarkDirty.add(newNode.id as AnyNodeId)
@@ -442,6 +909,7 @@ export const updateNodesAction = (
     for (const { id, data } of updates) {
       const currentNode = nextNodes[id]
       if (!currentNode) continue
+      const updatedNode = parseUpdatedNode(currentNode, data)
 
       // Handle Reparenting Logic
       if (data.parentId !== undefined && data.parentId !== currentNode.parentId) {
@@ -480,7 +948,7 @@ export const updateNodesAction = (
       }
 
       // Apply the update
-      nextNodes[id] = { ...nextNodes[id], ...data } as AnyNode
+      nextNodes[id] = updatedNode
     }
 
     return { nodes: nextNodes }

packages/core/src/store/actions/node-mutation-sanitize.test.ts

@@ -0,0 +1,175 @@
+import { beforeEach, describe, expect, test } from 'bun:test'
+import type { AnyNode, AnyNodeId } from '../../schema/types'
+import useScene from '../use-scene'
+
+type RafFn = (cb: (t: number) => void) => number
+;(globalThis as unknown as { requestAnimationFrame?: RafFn }).requestAnimationFrame ??= ((
+  cb: (t: number) => void,
+) => {
+  cb(0)
+  return 0
+}) as RafFn
+;(globalThis as unknown as { cancelAnimationFrame?: (id: number) => void }).cancelAnimationFrame ??=
+  () => {}
+
+const SHELF_ID = 'shelf_sanitize' as AnyNodeId
+const SOLAR_PANEL_ID = 'sp_x' as AnyNodeId
+
+function makeShelf(overrides: Partial<AnyNode> = {}): AnyNode {
+  return {
+    id: SHELF_ID,
+    type: 'shelf',
+    parentId: null,
+    object: 'node',
+    visible: true,
+    name: 'Shelf',
+    metadata: {},
+    children: [],
+    position: [0, 0, 0],
+    rotation: [0, 0, 0],
+    width: 1.2,
+    depth: 0.3,
+    thickness: 0.04,
+    height: 0.9,
+    style: 'wall-shelf',
+    rows: 1,
+    columns: 1,
+    withBack: false,
+    withSides: true,
+    withBottom: false,
+    bracketStyle: 'minimal',
+    ...overrides,
+  } as unknown as AnyNode
+}
+
+function makeSolarPanel(): AnyNode {
+  return {
+    id: SOLAR_PANEL_ID,
+    type: 'solar-panel',
+    parentId: null,
+    object: 'node',
+    visible: true,
+    name: 'Panel',
+    metadata: {},
+    position: [0, 0, 0],
+    rotation: 0,
+    rows: 2,
+    columns: 3,
+    panelWidth: 1,
+    panelHeight: 1.65,
+    gapX: 0.02,
+    gapY: 0.02,
+    mountingType: 'flush',
+    tiltAngle: 15,
+    standoffHeight: 0.05,
+    frameThickness: 0.04,
+    frameDepth: 0.04,
+  } as unknown as AnyNode
+}
+
+function shelf() {
+  return useScene.getState().nodes[SHELF_ID] as Extract<AnyNode, { type: 'shelf' }>
+}
+
+describe('node mutation numeric sanitization', () => {
+  beforeEach(() => {
+    useScene.setState({
+      nodes: {
+        [SHELF_ID]: makeShelf(),
+        [SOLAR_PANEL_ID]: makeSolarPanel(),
+      },
+      rootNodeIds: [SHELF_ID, SOLAR_PANEL_ID],
+      dirtyNodes: new Set(),
+      collections: {},
+      readOnly: false,
+    } as never)
+    useScene.temporal.getState().clear()
+  })
+
+  test('drops NaN numeric updates while preserving other fields in the patch', () => {
+    useScene.getState().updateNode(SHELF_ID, {
+      thickness: Number.NaN,
+      name: 'Renamed after NaN',
+    } as Partial<AnyNode>)
+
+    expect(shelf().thickness).toBe(0.04)
+    expect(Number.isFinite(shelf().thickness)).toBe(true)
+    expect(shelf().name).toBe('Renamed after NaN')
+  })
+
+  test('drops Infinity numeric updates while preserving later normal updates', () => {
+    useScene.getState().updateNode(SHELF_ID, {
+      width: Infinity,
+      name: 'Renamed after Infinity',
+    } as Partial<AnyNode>)
+
+    expect(shelf().width).toBe(1.2)
+    expect(Number.isFinite(shelf().width)).toBe(true)
+    expect(shelf().name).toBe('Renamed after Infinity')
+
+    useScene.getState().updateNode(SHELF_ID, {
+      name: 'Clean rename',
+    } as Partial<AnyNode>)
+
+    expect(shelf().name).toBe('Clean rename')
+  })
+
+  test('clamps out-of-range numeric updates to the node schema bounds', () => {
+    useScene.getState().updateNode(SHELF_ID, {
+      width: 99,
+      thickness: -1,
+    } as Partial<AnyNode>)
+
+    expect(shelf().width).toBe(3)
+    expect(shelf().thickness).toBe(0.01)
+  })
+
+  test('preserves extra fields while sanitizing numeric updates', () => {
+    useScene.setState({
+      nodes: {
+        [SHELF_ID]: {
+          ...makeShelf(),
+          legacyField: 'current',
+        } as unknown as AnyNode,
+      },
+      rootNodeIds: [SHELF_ID],
+    } as never)
+
+    useScene.getState().updateNode(SHELF_ID, {
+      width: Infinity,
+      legacyPatch: 'patch',
+    } as Partial<AnyNode>)
+
+    const node = useScene.getState().nodes[SHELF_ID] as Record<string, unknown>
+    expect(node.width).toBe(1.2)
+    expect(node.legacyField).toBe('current')
+    expect(node.legacyPatch).toBe('patch')
+  })
+
+  test('allows non-canonical ids to receive updates', () => {
+    useScene.getState().updateNode(SOLAR_PANEL_ID, {
+      name: 'Updated panel',
+    } as Partial<AnyNode>)
+
+    const panel = useScene.getState().nodes[SOLAR_PANEL_ID] as { name?: string }
+    expect(panel.name).toBe('Updated panel')
+  })
+
+  test('sanitizes non-finite numeric values during create', () => {
+    const createdId = 'shelf_created' as AnyNodeId
+
+    useScene.getState().createNode(
+      makeShelf({
+        id: createdId,
+        width: Infinity,
+        thickness: Number.NaN,
+      } as Partial<AnyNode>),
+    )
+
+    const created = useScene.getState().nodes[createdId] as Extract<AnyNode, { type: 'shelf' }>
+    expect(created.width).toBe(1.2)
+    expect(created.thickness).toBe(0.04)
+    expect(Number.isFinite(created.width)).toBe(true)
+    expect(Number.isFinite(created.thickness)).toBe(true)
+  })
+})

packages/core/src/store/use-scene.ts

@@ -13,6 +13,7 @@ import {
   type RoofSegmentNode,
   type RoofType,
 } from '../schema/nodes/roof-segment'
+import { ShelfNode as ShelfNodeSchema } from '../schema/nodes/shelf'
 import { SiteNode } from '../schema/nodes/site'
 import { StairNode as StairNodeSchema } from '../schema/nodes/stair'
 import { StairSegmentNode as StairSegmentNodeSchema } from '../schema/nodes/stair-segment'
@@ -24,6 +25,11 @@ function getFiniteNumber(value: unknown, fallback: number) {
   return typeof value === 'number' && Number.isFinite(value) ? value : fallback
 }
 
+function getFiniteNumberInRange(value: unknown, fallback: number, min: number, max: number) {
+  const finite = getFiniteNumber(value, fallback)
+  return Math.min(Math.max(finite, min), max)
+}
+
 function getBoolean(value: unknown, fallback: boolean) {
   return typeof value === 'boolean' ? value : fallback
 }
@@ -112,6 +118,37 @@ function normalizeDoorNode(node: Record<string, unknown>) {
   return parsed.success ? { ...node, ...parsed.data } : null
 }
 
+function normalizeShelfNode(node: Record<string, unknown>) {
+  const sanitized = {
+    ...node,
+    children: getStringArray(node.children),
+    position: getVector3(node.position, [0, 0, 0]),
+    rotation: getVector3(node.rotation, [0, 0, 0]),
+    width: getFiniteNumberInRange(node.width, 1.2, 0.3, 3.0),
+    depth: getFiniteNumberInRange(node.depth, 0.3, 0.1, 1.0),
+    thickness: getFiniteNumberInRange(node.thickness, 0.04, 0.01, 0.1),
+    height: getFiniteNumberInRange(node.height, 0.9, 0.05, 2.5),
+    rows: Math.round(getFiniteNumberInRange(node.rows, 1, 1, 8)),
+    columns: Math.round(getFiniteNumberInRange(node.columns, 1, 1, 6)),
+    style: getEnumValue(
+      node.style,
+      ['wall-shelf', 'bookshelf', 'open-rack', 'cubby'] as const,
+      'wall-shelf',
+    ),
+    withBack: getBoolean(node.withBack, false),
+    withSides: getBoolean(node.withSides, true),
+    withBottom: getBoolean(node.withBottom, false),
+    bracketStyle: getEnumValue(
+      node.bracketStyle,
+      ['minimal', 'industrial', 'hidden'] as const,
+      'minimal',
+    ),
+  }
+
+  const parsed = ShelfNodeSchema.safeParse(sanitized)
+  return parsed.success ? parsed.data : null
+}
+
 function migrateWallSurfaceMaterials(node: Record<string, any>) {
   const hasInterior =
     node.interiorMaterial !== undefined || typeof node.interiorMaterialPreset === 'string'
@@ -396,14 +433,11 @@ function migrateNodes(nodes: Record<string, any>): Record<string, AnyNode> {
       patchedNodes[id] = migrateWallSurfaceMaterials(patchedNodes[id])
     }
 
-    // Shelf v2: hosting was added in this migration cycle. Older shelves
-    // (saved before the schema gained `children`) need the field
-    // initialised so `createNode(item, shelfId)` finds an array to
-    // append the child id to — without this the host item ends up
-    // orphaned (parented in scene state but not in the shelf's
-    // children list, so the renderer doesn't mount it).
-    if (node.type === 'shelf' && !Array.isArray(node.children)) {
-      patchedNodes[id] = { ...node, children: [] }
+    if (node.type === 'shelf') {
+      const normalized = normalizeShelfNode(node)
+      if (normalized) {
+        patchedNodes[id] = normalized
+      }
     }
 
     // Roof-segment hosting was added in this migration cycle (the same

packages/editor/src/components/editor-2d/renderers/floorplan-registry-layer.tsx

@@ -287,39 +287,16 @@ export const FloorplanRegistryLayer = memo(function FloorplanRegistryLayer() {
         //
         // The live-transform contract varies per kind (see
         // wiki/architecture/tools.md "useLiveTransforms contract is
-        // per-kind, not generic"); we narrow per kind here:
-        //   - item: world-plan position frame. Override `position` +
-        //     `rotation` and force `parentId: null` so the resolver
-        //     treats them as world coords directly.
-        //   - slab / ceiling: position is a translation **delta**
-        //     (`[Δx, 0, Δz]`). Translate the polygon + holes by the
-        //     delta — the floor-plan builder draws the polygon at its
-        //     new location, mirroring the 3D `<group position={delta}>`
-        //     visual without forcing per-tick CSG scene writes.
+        // per-kind, not generic"); position-carrying floor-placed kinds
+        // publish canonical X/Z, while slab / ceiling publish a polygon
+        // translation delta.
         const live = liveTransforms.get(id)
         let effectiveNode: AnyNode = node
         if (live) {
-          if (node.type === 'item' || node.type === 'shelf') {
-            // World-plan position kinds: the live transform carries the
-            // node's intended position/rotation in level-local coords.
-            // Override both and force `parentId: null` so the floor-plan
-            // resolver treats `position` as world plan coords directly
-            // (skipping the parent-chain transform composition).
-            effectiveNode = {
-              ...node,
-              position: live.position,
-              rotation: [0, live.rotation, 0] as [number, number, number],
-              parentId: null,
-            } as AnyNode
-          } else if (node.type === 'column') {
-            // Same world-plan override as item/shelf, but column stores its
-            // Y rotation as a scalar (not a tuple).
-            effectiveNode = {
-              ...node,
-              position: live.position,
-              rotation: live.rotation,
-              parentId: null,
-            } as AnyNode
+          const floorPlaced = def?.capabilities?.floorPlaced
+          const hasPosition = Array.isArray((node as { position?: unknown }).position)
+          if (floorPlaced && hasPosition) {
+            effectiveNode = applyPositionLiveTransform(node, live)
           } else if (node.type === 'slab' || node.type === 'ceiling' || node.type === 'zone') {
             const dx = live.position[0]
             const dz = live.position[2]
@@ -1591,6 +1568,29 @@ function InteractiveGeometry({
 
 // ── Helpers ──────────────────────────────────────────────────────────
 
+function applyPositionLiveTransform(
+  node: AnyNode,
+  live: { position: [number, number, number]; rotation: number },
+): AnyNode {
+  const currentRotation = (node as { rotation?: unknown }).rotation
+  const rotation = Array.isArray(currentRotation)
+    ? ([
+        (currentRotation[0] as number) ?? 0,
+        live.rotation,
+        (currentRotation[2] as number) ?? 0,
+      ] as [number, number, number])
+    : typeof currentRotation === 'number'
+      ? live.rotation
+      : currentRotation
+
+  return {
+    ...node,
+    position: live.position,
+    ...(rotation !== undefined ? { rotation } : {}),
+    parentId: null,
+  } as AnyNode
+}
+
 function buildContext(
   node: AnyNode,
   nodes: Record<string, AnyNode>,

packages/editor/src/components/editor/group-move-handle.tsx

@@ -8,10 +8,10 @@ import { OrthographicCamera, Plane, Vector2, Vector3 } from 'three'
 import { sfxEmitter } from '../../lib/sfx-bus'
 import useEditor from '../../store/use-editor'
 import {
+  CORNER_OFFSET,
   classifyParticipant,
   collectParticipants,
   computeGroupBox,
-  CORNER_OFFSET,
   expandToComponent,
   type Vec2,
 } from './group-transform-shared'

packages/editor/src/components/editor/group-rotate-handle.tsx

@@ -21,11 +21,15 @@ import {
   ARROW_HOVER_COLOR,
   ARROW_SCALE,
   createRotateArrowHandleGeometry,
+  createRotateArrowHitAreaGeometry,
   GuideRing,
+  InvisibleHandleHitArea,
+  NO_RAYCAST,
   RotationGuide,
   type RotationGuideData,
   swallowNextClick,
   useArrowMaterial,
+  useInvisibleHitAreaMaterial,
 } from './node-arrow-handles'
 
 const ROTATE_SNAP = Math.PI / 12 // 15°
@@ -74,7 +78,9 @@ export function GroupRotateHandle() {
 function GroupRotateHandleInner({ ids }: { ids: string[] }) {
   const { camera, raycaster, gl, scene } = useThree()
   const arrowGeometry = useMemo(() => createRotateArrowHandleGeometry(), [])
+  const hitGeometry = useMemo(() => createRotateArrowHitAreaGeometry(), [])
   const arrowMaterial = useArrowMaterial()
+  const hitMaterial = useInvisibleHitAreaMaterial()
   const [isHovered, setIsHovered] = useState(false)
   const [isDragging, setIsDragging] = useState(false)
   const [guide, setGuide] = useState<RotationGuideData | null>(null)
@@ -85,11 +91,13 @@ function GroupRotateHandleInner({ ids }: { ids: string[] }) {
     arrowMaterial.color.set(isHovered ? ARROW_HOVER_COLOR : ARROW_COLOR)
   }, [arrowMaterial, isHovered])
   useEffect(() => () => arrowGeometry.dispose(), [arrowGeometry])
+  useEffect(() => () => hitGeometry.dispose(), [hitGeometry])
   useEffect(() => () => arrowMaterial.dispose(), [arrowMaterial])
   useEffect(() => () => dragCleanupRef.current?.(), [])
 
   const zoom = camera instanceof OrthographicCamera ? 1 / camera.zoom : 1
-  const scale = (isHovered ? 1.12 : 1) * zoom * ARROW_SCALE * 1.05
+  const baseScale = zoom * ARROW_SCALE * 1.05
+  const scale = (isHovered ? 1.12 : 1) * baseScale
 
   // World-space bounding box of the selected meshes. Levels are axis-aligned in
   // XZ, so world XZ coincides with each node's level-local placement — letting
@@ -100,11 +108,7 @@ function GroupRotateHandleInner({ ids }: { ids: string[] }) {
   const rest = useMemo(() => {
     const box = computeGroupBox(ids)
     if (!box) return null
-    const pivot = new Vector3(
-      (box.min.x + box.max.x) / 2,
-      box.min.y,
-      (box.min.z + box.max.z) / 2,
-    )
+    const pivot = new Vector3((box.min.x + box.max.x) / 2, box.min.y, (box.min.z + box.max.z) / 2)
     const corner = new Vector3(
       box.max.x + CORNER_OFFSET,
       (box.min.y + box.max.y) / 2,
@@ -307,11 +311,10 @@ function GroupRotateHandleInner({ ids }: { ids: string[] }) {
           <GuideRing radius={0.2 * scale} y={0} />
         </group>
       )}
-      <group position={[corner.x, corner.y, corner.z]} scale={scale}>
-        <mesh
-          frustumCulled={false}
-          geometry={arrowGeometry}
-          material={arrowMaterial}
+      <group position={[corner.x, corner.y, corner.z]}>
+        <InvisibleHandleHitArea
+          geometry={hitGeometry}
+          material={hitMaterial}
           onPointerDown={activate}
           onPointerEnter={(event) => {
             event.stopPropagation()
@@ -323,7 +326,15 @@ function GroupRotateHandleInner({ ids }: { ids: string[] }) {
             setIsHovered(false)
             if (document.body.style.cursor === 'grab') document.body.style.cursor = ''
           }}
+          scale={baseScale}
+        />
+        <mesh
+          frustumCulled={false}
+          geometry={arrowGeometry}
+          material={arrowMaterial}
+          raycast={NO_RAYCAST}
           renderOrder={1010}
+          scale={scale}
         />
       </group>
       {guide ? <RotationGuide data={guide} /> : null}

packages/editor/src/components/editor/handles/handle-arrow.tsx

@@ -0,0 +1,523 @@
+'use client'
+
+import { type Cursor, emitter } from '@pascal-app/core'
+import type { ThreeEvent } from '@react-three/fiber'
+import { type ReactNode, useEffect, useMemo, useRef } from 'react'
+import {
+  BoxGeometry,
+  type BufferGeometry,
+  CircleGeometry,
+  Color,
+  CylinderGeometry,
+  DoubleSide,
+  ExtrudeGeometry,
+  type Group,
+  Shape,
+  TorusGeometry,
+} from 'three'
+import { mergeGeometries } from 'three/examples/jsm/utils/BufferGeometryUtils.js'
+import { MeshBasicNodeMaterial } from 'three/webgpu'
+import { EDITOR_LAYER } from '../../../lib/constants'
+
+export const ARROW_SCALE = 0.65
+export const ARROW_COLOR = '#8381ed'
+export const ARROW_HOVER_COLOR = '#a5b4fc'
+export const NO_RAYCAST = () => null
+export const HIT_AREA_MARGIN = 0.035
+
+const HIT_AREA_RENDER_ORDER = 1011
+const HIT_AREA_THICKNESS = 0.08
+const CHEVRON_MIN_X = -0.2
+const CHEVRON_MAX_X = 0.22
+const CHEVRON_HALF_WIDTH = 0.12
+const CHEVRON_NOTCH_X = -0.04
+const CHEVRON_SHAFT_HALF_WIDTH = 0.035
+const CHEVRON_DEPTH = 0.08
+const CHEVRON_BEVEL_THICKNESS = 0.035
+const CHEVRON_BEVEL_SIZE = 0.03
+const CHEVRON_BEVEL_SEGMENTS = 10
+const MOVE_CROSS_HALF_LENGTH = 0.36
+const MOVE_CROSS_SHAFT_HALF_WIDTH = 0.03
+const MOVE_CROSS_HEAD_HALF_WIDTH = 0.12
+const MOVE_CROSS_HEAD_INSET = 0.2
+const MOVE_CROSS_DEPTH = 0.06
+const MOVE_CROSS_BEVEL_THICKNESS = 0.018
+const MOVE_CROSS_BEVEL_SIZE = 0.012
+const MOVE_CROSS_BEVEL_SEGMENTS = 6
+const ROTATE_HANDLE_RADIUS = 0.2
+const ROTATE_HANDLE_HALF_SWEEP = Math.PI / 3
+const ROTATE_RIBBON_HALF_WIDTH = 0.02
+const ROTATE_HEAD_HALF_WIDTH = 0.045
+const TRACKER_CUBE_SIZE = 0.16
+export const CORNER_HEX_RADIUS = 0.16
+
+export type HandleArrowShape = 'chevron' | 'cross' | 'curved-arrow' | 'tracker' | 'corner-picker'
+export type HandleArrowInputShape = HandleArrowShape | 'arrow' | 'move-cross'
+
+export type HandleArrowPlacement = {
+  position: readonly [number, number, number]
+  rotation?: readonly [number, number, number]
+  baseScale: number
+}
+
+type PointerHandler = (event: ThreeEvent<PointerEvent>) => void
+
+export type HandleArrowProps = {
+  shape: HandleArrowInputShape
+  placement: HandleArrowPlacement
+  hover: boolean
+  cursor: Cursor
+  onHoverChange: (hovered: boolean) => void
+  onPointerDown: PointerHandler
+  activeCursor?: Cursor
+  children?: ReactNode
+  hoverScale?: number
+  indicatorRotation?: readonly [number, number, number]
+  onPointerEnter?: PointerHandler
+  onPointerLeave?: PointerHandler
+}
+
+function normalizeHandleArrowShape(shape: HandleArrowInputShape, cursor: Cursor): HandleArrowShape {
+  if (shape === 'arrow') return 'chevron'
+  if (shape === 'move-cross') return 'cross'
+  if (shape === 'chevron' && cursor === 'move') return 'cross'
+  return shape
+}
+
+// Two-headed curved-arrow silhouette for whole-node rotation handles
+// (today: the elevator's corner rotate gizmo). Symmetric arc centred on
+// +X with sweeps to +/-halfSweep, arrowhead wings + tangentially-extended
+// tips at each end. Drawn in 2D then extruded and rotated to lie in the
+// XZ plane - same final-orientation contract as the chevron, so the
+// outer rotation Y and inner-rotation chain in the renderer are reused
+// unchanged.
+export function createRotateArrowHandleGeometry() {
+  const R = 0.2
+  const ribbonHalfWidth = 0.02
+  const halfSweep = Math.PI / 3
+  const headHalfWidth = 0.045
+  const headOvershoot = 0.075
+  const rIn = R - ribbonHalfWidth
+  const rOut = R + ribbonHalfWidth
+  const a1 = halfSweep
+  const a2 = -halfSweep
+
+  const tip1: [number, number] = [
+    R * Math.cos(a1) - headOvershoot * Math.sin(a1),
+    R * Math.sin(a1) + headOvershoot * Math.cos(a1),
+  ]
+  const tip2: [number, number] = [
+    R * Math.cos(a2) + headOvershoot * Math.sin(a2),
+    R * Math.sin(a2) - headOvershoot * Math.cos(a2),
+  ]
+  const innerWing1: [number, number] = [
+    (rIn - headHalfWidth) * Math.cos(a1),
+    (rIn - headHalfWidth) * Math.sin(a1),
+  ]
+  const outerWing1: [number, number] = [
+    (rOut + headHalfWidth) * Math.cos(a1),
+    (rOut + headHalfWidth) * Math.sin(a1),
+  ]
+  const innerWing2: [number, number] = [
+    (rIn - headHalfWidth) * Math.cos(a2),
+    (rIn - headHalfWidth) * Math.sin(a2),
+  ]
+  const outerWing2: [number, number] = [
+    (rOut + headHalfWidth) * Math.cos(a2),
+    (rOut + headHalfWidth) * Math.sin(a2),
+  ]
+  const innerCorner1: [number, number] = [rIn * Math.cos(a1), rIn * Math.sin(a1)]
+  const outerCorner1: [number, number] = [rOut * Math.cos(a1), rOut * Math.sin(a1)]
+  const innerCorner2: [number, number] = [rIn * Math.cos(a2), rIn * Math.sin(a2)]
+  const outerCorner2: [number, number] = [rOut * Math.cos(a2), rOut * Math.sin(a2)]
+
+  const shape = new Shape()
+  shape.moveTo(innerCorner1[0], innerCorner1[1])
+  shape.lineTo(innerWing1[0], innerWing1[1])
+  shape.lineTo(tip1[0], tip1[1])
+  shape.lineTo(outerWing1[0], outerWing1[1])
+  shape.lineTo(outerCorner1[0], outerCorner1[1])
+  shape.absarc(0, 0, rOut, a1, a2, true)
+  shape.lineTo(outerWing2[0], outerWing2[1])
+  shape.lineTo(tip2[0], tip2[1])
+  shape.lineTo(innerWing2[0], innerWing2[1])
+  shape.lineTo(innerCorner2[0], innerCorner2[1])
+  shape.absarc(0, 0, rIn, a2, a1, false)
+  shape.closePath()
+
+  const geometry = new ExtrudeGeometry(shape, {
+    depth: 0.06,
+    bevelEnabled: true,
+    bevelThickness: 0.018,
+    bevelSize: 0.012,
+    bevelOffset: 0,
+    bevelSegments: 6,
+    curveSegments: 24,
+    steps: 1,
+  })
+  geometry.translate(0, 0, -0.03)
+  geometry.rotateX(-Math.PI / 2)
+  geometry.computeVertexNormals()
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+// Reused chevron+shaft silhouette. The chevron points along +X by default;
+// callers rotate it around Y for Z-axis handles and into a vertical frame for
+// Y-axis handles.
+export function createArrowHandleGeometry() {
+  const shape = new Shape()
+  shape.moveTo(CHEVRON_MAX_X, 0)
+  shape.lineTo(CHEVRON_NOTCH_X, CHEVRON_HALF_WIDTH)
+  shape.lineTo(CHEVRON_NOTCH_X, CHEVRON_SHAFT_HALF_WIDTH)
+  shape.lineTo(CHEVRON_MIN_X, CHEVRON_SHAFT_HALF_WIDTH)
+  shape.lineTo(CHEVRON_MIN_X, -CHEVRON_SHAFT_HALF_WIDTH)
+  shape.lineTo(CHEVRON_NOTCH_X, -CHEVRON_SHAFT_HALF_WIDTH)
+  shape.lineTo(CHEVRON_NOTCH_X, -CHEVRON_HALF_WIDTH)
+  shape.lineTo(CHEVRON_MAX_X, 0)
+  const geometry = new ExtrudeGeometry(shape, {
+    depth: CHEVRON_DEPTH,
+    bevelEnabled: true,
+    bevelThickness: CHEVRON_BEVEL_THICKNESS,
+    bevelSize: CHEVRON_BEVEL_SIZE,
+    bevelOffset: 0,
+    bevelSegments: CHEVRON_BEVEL_SEGMENTS,
+    curveSegments: 16,
+    steps: 1,
+  })
+  geometry.translate(0, 0, -CHEVRON_DEPTH / 2)
+  geometry.rotateX(-Math.PI / 2)
+  geometry.computeVertexNormals()
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+function createDoubleArrowShape(): Shape {
+  const shape = new Shape()
+  shape.moveTo(MOVE_CROSS_HALF_LENGTH, 0)
+  shape.lineTo(MOVE_CROSS_HEAD_INSET, MOVE_CROSS_HEAD_HALF_WIDTH)
+  shape.lineTo(MOVE_CROSS_HEAD_INSET, MOVE_CROSS_SHAFT_HALF_WIDTH)
+  shape.lineTo(-MOVE_CROSS_HEAD_INSET, MOVE_CROSS_SHAFT_HALF_WIDTH)
+  shape.lineTo(-MOVE_CROSS_HEAD_INSET, MOVE_CROSS_HEAD_HALF_WIDTH)
+  shape.lineTo(-MOVE_CROSS_HALF_LENGTH, 0)
+  shape.lineTo(-MOVE_CROSS_HEAD_INSET, -MOVE_CROSS_HEAD_HALF_WIDTH)
+  shape.lineTo(-MOVE_CROSS_HEAD_INSET, -MOVE_CROSS_SHAFT_HALF_WIDTH)
+  shape.lineTo(MOVE_CROSS_HEAD_INSET, -MOVE_CROSS_SHAFT_HALF_WIDTH)
+  shape.lineTo(MOVE_CROSS_HEAD_INSET, -MOVE_CROSS_HEAD_HALF_WIDTH)
+  shape.closePath()
+  return shape
+}
+
+export function createMoveCrossHandleGeometry() {
+  const shape = createDoubleArrowShape()
+  const extrudeOpts = {
+    depth: MOVE_CROSS_DEPTH,
+    bevelEnabled: true,
+    bevelThickness: MOVE_CROSS_BEVEL_THICKNESS,
+    bevelSize: MOVE_CROSS_BEVEL_SIZE,
+    bevelOffset: 0,
+    bevelSegments: MOVE_CROSS_BEVEL_SEGMENTS,
+    curveSegments: 8,
+    steps: 1,
+  }
+  const armX = new ExtrudeGeometry(shape, extrudeOpts)
+  armX.translate(0, 0, -MOVE_CROSS_DEPTH / 2)
+  armX.rotateX(-Math.PI / 2)
+  const armZ = armX.clone()
+  armZ.rotateY(Math.PI / 2)
+  const merged = mergeGeometries([armX, armZ], false)
+  if (!merged) {
+    armZ.dispose()
+    armX.computeVertexNormals()
+    armX.computeBoundingSphere()
+    return armX
+  }
+  armX.dispose()
+  armZ.dispose()
+  merged.computeVertexNormals()
+  merged.computeBoundingSphere()
+  return merged
+}
+
+export function createArrowHitAreaGeometry() {
+  const length = CHEVRON_MAX_X - CHEVRON_MIN_X + HIT_AREA_MARGIN * 2
+  const centerX = (CHEVRON_MIN_X + CHEVRON_MAX_X) / 2
+  const geometry = new CylinderGeometry(
+    CHEVRON_HALF_WIDTH + HIT_AREA_MARGIN,
+    CHEVRON_HALF_WIDTH + HIT_AREA_MARGIN,
+    length,
+    16,
+  )
+  geometry.rotateZ(-Math.PI / 2)
+  geometry.translate(centerX, 0, 0)
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+function createMoveCrossHitAreaGeometry() {
+  const geometry = new CylinderGeometry(
+    MOVE_CROSS_HALF_LENGTH + HIT_AREA_MARGIN,
+    MOVE_CROSS_HALF_LENGTH + HIT_AREA_MARGIN,
+    HIT_AREA_THICKNESS,
+    32,
+  )
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+export function createRotateArrowHitAreaGeometry() {
+  const halfSweep = ROTATE_HANDLE_HALF_SWEEP + HIT_AREA_MARGIN / ROTATE_HANDLE_RADIUS
+  const geometry = new TorusGeometry(
+    ROTATE_HANDLE_RADIUS,
+    ROTATE_RIBBON_HALF_WIDTH + ROTATE_HEAD_HALF_WIDTH + HIT_AREA_MARGIN,
+    10,
+    64,
+    halfSweep * 2,
+  )
+  geometry.rotateZ(-halfSweep)
+  geometry.rotateX(-Math.PI / 2)
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+function createTrackerHitAreaGeometry() {
+  const size = TRACKER_CUBE_SIZE + HIT_AREA_MARGIN * 2
+  const geometry = new BoxGeometry(size, size, size)
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+export function createEndpointHitAreaGeometry(radius: number) {
+  const geometry = new CylinderGeometry(
+    radius + HIT_AREA_MARGIN,
+    radius + HIT_AREA_MARGIN,
+    HIT_AREA_THICKNESS,
+    24,
+  )
+  geometry.rotateX(Math.PI / 2)
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+function createHandleArrowGeometry(shape: HandleArrowShape) {
+  if (shape === 'chevron') return createArrowHandleGeometry()
+  if (shape === 'cross') return createMoveCrossHandleGeometry()
+  if (shape === 'curved-arrow') return createRotateArrowHandleGeometry()
+  if (shape === 'tracker') {
+    const geometry = new BoxGeometry(TRACKER_CUBE_SIZE, TRACKER_CUBE_SIZE, TRACKER_CUBE_SIZE)
+    geometry.computeBoundingSphere()
+    return geometry
+  }
+  const geometry = new CircleGeometry(CORNER_HEX_RADIUS, 6)
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+function createHandleArrowHitGeometry(shape: HandleArrowShape) {
+  if (shape === 'chevron') return createArrowHitAreaGeometry()
+  if (shape === 'cross') return createMoveCrossHitAreaGeometry()
+  if (shape === 'curved-arrow') return createRotateArrowHitAreaGeometry()
+  if (shape === 'tracker') return createTrackerHitAreaGeometry()
+  const geometry = new CircleGeometry(CORNER_HEX_RADIUS, 6)
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+let sharedHitAreaMaterial: MeshBasicNodeMaterial | null = null
+let sharedHitAreaMaterialRefs = 0
+
+function createInvisibleHitAreaMaterial() {
+  return new MeshBasicNodeMaterial({
+    color: new Color('#ffffff'),
+    colorWrite: false,
+    depthTest: false,
+    depthWrite: false,
+    opacity: 0,
+    side: DoubleSide,
+    transparent: true,
+  })
+}
+
+export function useInvisibleHitAreaMaterial(): MeshBasicNodeMaterial {
+  const materialRef = useRef<MeshBasicNodeMaterial | null>(null)
+  if (!materialRef.current) {
+    sharedHitAreaMaterial ??= createInvisibleHitAreaMaterial()
+    materialRef.current = sharedHitAreaMaterial
+  }
+  useEffect(() => {
+    sharedHitAreaMaterialRefs += 1
+    return () => {
+      sharedHitAreaMaterialRefs -= 1
+      if (sharedHitAreaMaterialRefs <= 0 && sharedHitAreaMaterial) {
+        sharedHitAreaMaterial.dispose()
+        sharedHitAreaMaterial = null
+        sharedHitAreaMaterialRefs = 0
+      }
+    }
+  }, [])
+  return materialRef.current
+}
+
+export function InvisibleHandleHitArea({
+  geometry,
+  material,
+  onPointerDown,
+  onPointerEnter,
+  onPointerLeave,
+  scale,
+}: {
+  geometry: BufferGeometry
+  material: MeshBasicNodeMaterial
+  onPointerDown: PointerHandler
+  onPointerEnter: PointerHandler
+  onPointerLeave: PointerHandler
+  scale: number
+}) {
+  return (
+    <mesh
+      frustumCulled={false}
+      geometry={geometry}
+      layers={EDITOR_LAYER}
+      material={material}
+      onPointerDown={onPointerDown}
+      onPointerEnter={onPointerEnter}
+      onPointerLeave={onPointerLeave}
+      renderOrder={HIT_AREA_RENDER_ORDER}
+      scale={scale}
+    />
+  )
+}
+
+export function useArrowMaterial(): MeshBasicNodeMaterial {
+  return useMemo(
+    () =>
+      new MeshBasicNodeMaterial({
+        color: new Color(ARROW_COLOR),
+        side: DoubleSide,
+        // `depthTest: false` keeps the chevron drawing on top of any
+        // geometry under it; `depthWrite: true` puts the chevron's depth
+        // into the scenePass buffer so the ink-edge shader's depth
+        // Laplacian fires on its silhouette from every angle. Without
+        // depthWrite, only the normal-discontinuity branch can detect
+        // the chevron, and that signal collapses when the arrow's faces
+        // happen to align with whatever sits behind them in screen space
+        // - which is why the lines used to drop out depending on the view.
+        depthTest: false,
+        depthWrite: true,
+        transparent: true,
+        opacity: 1,
+      }),
+    [],
+  )
+}
+
+function useHandleArrowMaterial(shape: HandleArrowShape): MeshBasicNodeMaterial {
+  return useMemo(
+    () =>
+      new MeshBasicNodeMaterial({
+        color: new Color(ARROW_COLOR),
+        side: DoubleSide,
+        transparent: true,
+        opacity: shape === 'corner-picker' ? 0.95 : 1,
+        depthTest: false,
+        depthWrite: shape !== 'corner-picker',
+      }),
+    [shape],
+  )
+}
+
+function indicatorRenderOrder(shape: HandleArrowShape) {
+  return shape === 'tracker' || shape === 'corner-picker' ? 1003 : 1010
+}
+
+export function HandleArrow({
+  shape,
+  placement,
+  hover,
+  cursor,
+  activeCursor,
+  children,
+  hoverScale = 1.12,
+  indicatorRotation,
+  onHoverChange,
+  onPointerDown,
+  onPointerEnter,
+  onPointerLeave,
+}: HandleArrowProps) {
+  const visualShape = normalizeHandleArrowShape(shape, cursor)
+  const geometry = useMemo(() => createHandleArrowGeometry(visualShape), [visualShape])
+  const hitGeometry = useMemo(() => createHandleArrowHitGeometry(visualShape), [visualShape])
+  const indicatorMaterial = useHandleArrowMaterial(visualShape)
+  const hitMaterial = useInvisibleHitAreaMaterial()
+  const rootRef = useRef<Group>(null)
+  const rotation: [number, number, number] = placement.rotation
+    ? [placement.rotation[0], placement.rotation[1], placement.rotation[2]]
+    : [0, 0, 0]
+  const localRotation: [number, number, number] = indicatorRotation
+    ? [indicatorRotation[0], indicatorRotation[1], indicatorRotation[2]]
+    : [0, 0, 0]
+  const scale = (hover ? hoverScale : 1) * placement.baseScale
+  const hitScale = visualShape === 'corner-picker' ? scale : placement.baseScale
+
+  useEffect(() => {
+    indicatorMaterial.color.set(hover ? ARROW_HOVER_COLOR : ARROW_COLOR)
+  }, [indicatorMaterial, hover])
+  useEffect(() => {
+    const hideForCapture = () => {
+      if (rootRef.current) rootRef.current.visible = false
+    }
+    const restoreAfterCapture = () => {
+      if (rootRef.current) rootRef.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(() => () => geometry.dispose(), [geometry])
+  useEffect(() => () => hitGeometry.dispose(), [hitGeometry])
+  useEffect(() => () => indicatorMaterial.dispose(), [indicatorMaterial])
+
+  const handleEnter: PointerHandler = (event) => {
+    event.stopPropagation()
+    onHoverChange(true)
+    if (!activeCursor || document.body.style.cursor !== activeCursor) {
+      document.body.style.cursor = cursor
+    }
+    onPointerEnter?.(event)
+  }
+  const handleLeave: PointerHandler = (event) => {
+    event.stopPropagation()
+    onHoverChange(false)
+    if (document.body.style.cursor === cursor) {
+      document.body.style.cursor = ''
+    }
+    onPointerLeave?.(event)
+  }
+
+  return (
+    <group position={placement.position} ref={rootRef} rotation={rotation}>
+      {children}
+      <group rotation={localRotation}>
+        <InvisibleHandleHitArea
+          geometry={hitGeometry}
+          material={hitMaterial}
+          onPointerDown={onPointerDown}
+          onPointerEnter={handleEnter}
+          onPointerLeave={handleLeave}
+          scale={hitScale}
+        />
+        <mesh
+          frustumCulled={false}
+          geometry={geometry}
+          material={indicatorMaterial}
+          raycast={NO_RAYCAST}
+          renderOrder={indicatorRenderOrder(visualShape)}
+          scale={scale}
+        />
+      </group>
+    </group>
+  )
+}

packages/editor/src/components/editor/handles/use-handle-drag.ts

@@ -0,0 +1,183 @@
+'use client'
+
+import {
+  type AnyNode,
+  type AnyNodeId,
+  type Cursor,
+  createSceneApi,
+  useLiveNodeOverrides,
+  useScene,
+} from '@pascal-app/core'
+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 { sfxEmitter } from '../../../lib/sfx-bus'
+
+export type HandleDragControls = {
+  onStart: (index: number, snapshot: AnyNode) => void
+  onEnd: () => void
+}
+
+type IntersectPlane = (
+  clientX: number,
+  clientY: number,
+  plane: Plane,
+  target: Vector3,
+) => Vector3 | null
+
+export type HandleDragStartContext = {
+  event: ThreeEvent<PointerEvent>
+  camera: Camera
+  intersectPlane: IntersectPlane
+  initialNode: AnyNode
+  node: AnyNode
+  nodeId: AnyNodeId
+  rideObject: Object3D
+  sceneApi: ReturnType<typeof createSceneApi>
+}
+
+export type HandleDragMoveContext = {
+  event: PointerEvent
+  intersectPlane: IntersectPlane
+}
+
+type HandleDragSession = {
+  move: (context: HandleDragMoveContext) => Partial<AnyNode> | null
+  onBegin?: () => void
+  onEnd?: () => void
+  overrideId?: AnyNodeId
+}
+
+type UseHandleDragArgs =
+  | {
+      kind: 'drag'
+      cursor: Cursor
+      dragControls: HandleDragControls
+      handleIndex: number
+      node: AnyNode
+      onStart: (context: HandleDragStartContext) => HandleDragSession | null
+      rideObject: Object3D
+      setIsDragging: (dragging: boolean) => void
+    }
+  | {
+      kind: 'tap'
+      onTap: (event: ThreeEvent<PointerEvent>) => void
+    }
+
+export function swallowNextClick() {
+  const swallow = (clickEvent: Event) => {
+    clickEvent.stopPropagation()
+    clickEvent.preventDefault()
+  }
+  window.addEventListener('click', swallow, { capture: true, once: true })
+  setTimeout(() => {
+    window.removeEventListener('click', swallow, { capture: true })
+  }, 300)
+}
+
+export function useHandleDrag(args: UseHandleDragArgs) {
+  const { camera, raycaster, gl } = useThree()
+  const dragCleanupRef = useRef<(() => void) | null>(null)
+
+  useEffect(() => () => dragCleanupRef.current?.(), [])
+
+  return (event: ThreeEvent<PointerEvent>) => {
+    event.stopPropagation()
+
+    if (args.kind === 'tap') {
+      sfxEmitter.emit('sfx:item-pick')
+      document.body.style.cursor = ''
+      args.onTap(event)
+      return
+    }
+
+    const { cursor, dragControls, handleIndex, node, rideObject, setIsDragging } = args
+    rideObject.updateMatrixWorld()
+
+    const ndc = new Vector2()
+    const intersectPlane: IntersectPlane = (clientX, clientY, plane, target) => {
+      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)
+      return raycaster.ray.intersectPlane(plane, target)
+    }
+
+    const nodeId = node.id as AnyNodeId
+    const sceneApi = createSceneApi(useScene)
+    const initialNode = (sceneApi.get(nodeId) ?? node) as AnyNode
+    const session = args.onStart({
+      event,
+      camera,
+      intersectPlane,
+      initialNode,
+      node,
+      nodeId,
+      rideObject,
+      sceneApi,
+    })
+    if (!session) return
+
+    const overrideId = session.overrideId ?? nodeId
+    document.body.style.cursor = cursor
+    sfxEmitter.emit('sfx:item-pick')
+    useViewer.getState().setInputDragging(true)
+    useScene.temporal.getState().pause()
+    setIsDragging(true)
+    dragControls.onStart(handleIndex, initialNode)
+    session.onBegin?.()
+
+    let lastPatch: Partial<AnyNode> | null = null
+
+    const onMove = (moveEvent: PointerEvent) => {
+      const patch = session.move({ event: moveEvent, intersectPlane })
+      if (!patch) return
+      lastPatch = patch
+      useLiveNodeOverrides.getState().set(overrideId, patch as Record<string, unknown>)
+      useScene.getState().markDirty(overrideId)
+    }
+
+    const cleanup = () => {
+      window.removeEventListener('pointermove', onMove)
+      window.removeEventListener('pointerup', onUp)
+      window.removeEventListener('pointercancel', onCancel)
+      if (document.body.style.cursor === cursor) {
+        document.body.style.cursor = ''
+      }
+      useScene.temporal.getState().resume()
+      useViewer.getState().setInputDragging(false)
+      setIsDragging(false)
+      session.onEnd?.()
+      dragControls.onEnd()
+      dragCleanupRef.current = null
+    }
+
+    const clearOverride = () => {
+      useLiveNodeOverrides.getState().clear(overrideId)
+      useScene.getState().markDirty(overrideId)
+    }
+
+    const onUp = () => {
+      swallowNextClick()
+      sfxEmitter.emit('sfx:item-place')
+      if (lastPatch) {
+        sceneApi.update(overrideId, lastPatch)
+      }
+      clearOverride()
+      cleanup()
+    }
+
+    const onCancel = () => {
+      clearOverride()
+      cleanup()
+    }
+
+    dragCleanupRef.current = cleanup
+    window.addEventListener('pointermove', onMove)
+    window.addEventListener('pointerup', onUp)
+    window.addEventListener('pointercancel', onCancel)
+  }
+}

packages/editor/src/components/editor/index.tsx

@@ -65,6 +65,7 @@ import { GroupRotateHandle } from './group-rotate-handle'
 import { NodeArrowHandles } from './node-arrow-handles'
 import { SelectionManager } from './selection-manager'
 import { SiteEdgeLabels } from './site-edge-labels'
+import { SlabHoleHighlights } from './slab-hole-highlights'
 import { SnapshotCaptureOverlay } from './snapshot-capture-overlay'
 import { type SnapshotCameraData, ThumbnailGenerator } from './thumbnail-generator'
 import { WallMeasurementLabel } from './wall-measurement-label'
@@ -610,6 +611,7 @@ const ViewerSceneContent = memo(function ViewerSceneContent({
       {!noEditing && <GroupRotateHandle />}
       {!noEditing && <GroupMoveHandle />}
       {!noEditing && <WallOpeningHighlights />}
+      {!noEditing && <SlabHoleHighlights />}
       {!noEditing && <WallMoveSideHandles />}
       {!noEditing && <FloatingActionMenu />}
       {!noEditing && <FloatingBuildingActionMenu />}

packages/editor/src/components/editor/selection-manager.tsx

@@ -1263,6 +1263,13 @@ export const SelectionManager = () => {
           }
         }
 
+        // Clicking any node (e.g. the slab surface outside a hole) exits slab
+        // hole-edit mode. The hole handles + hit mesh stopPropagation, so a
+        // click reaching here means the user clicked outside the hole.
+        if (useEditor.getState().editingHole) {
+          useEditor.getState().setEditingHole(null)
+        }
+
         activeStrategy.handleSelect(nodeToSelect, event.nativeEvent, modifierKeysRef.current)
 
         let nextMaterialTargetHandled = false

packages/editor/src/components/editor/slab-hole-highlights.tsx

@@ -0,0 +1,456 @@
+'use client'
+
+import {
+  type AnyNodeId,
+  type BuildingNode,
+  type LevelNode,
+  resolveBuildingForLevel,
+  resolveLevelId,
+  type SlabNode,
+  type SurfaceHoleMetadata,
+  sceneRegistry,
+  useLiveNodeOverrides,
+  useScene,
+} from '@pascal-app/core'
+import { useViewer } from '@pascal-app/viewer'
+import { createPortal, type ThreeEvent } from '@react-three/fiber'
+import { useCallback, useEffect, useMemo, useState } from 'react'
+import {
+  BoxGeometry,
+  BufferGeometry,
+  DoubleSide,
+  Float32BufferAttribute,
+  type Object3D,
+  ShapeUtils,
+  Vector2,
+} from 'three'
+import { LineBasicNodeMaterial, MeshBasicNodeMaterial } from 'three/webgpu'
+import { EDITOR_LAYER } from '../../lib/constants'
+import useEditor from '../../store/use-editor'
+import { swallowNextClick } from './handles/use-handle-drag'
+
+const ACCENT = 0x83_81_ed
+const SURFACE_OFFSET = 0.01
+const HIT_PADDING = 0.08
+const MIN_HIT_HEIGHT = 0.16
+
+const NO_RAYCAST = () => null
+let restoreNodeClickSuppression: (() => void) | null = null
+
+const outlineMaterial = new LineBasicNodeMaterial({
+  color: ACCENT,
+  depthTest: false,
+  depthWrite: false,
+})
+
+const fillMaterial = new MeshBasicNodeMaterial({
+  color: ACCENT,
+  transparent: true,
+  opacity: 0.5,
+  depthTest: false,
+  depthWrite: false,
+  side: DoubleSide,
+})
+
+// Invisible hit targets must stay out of the scene MRT pass; keep them on
+// EDITOR_LAYER even though they never write color.
+const hitMaterial = new MeshBasicNodeMaterial({
+  color: ACCENT,
+  colorWrite: false,
+  depthTest: false,
+  depthWrite: false,
+  opacity: 0,
+  side: DoubleSide,
+  transparent: true,
+})
+
+type HolePolygon = Array<[number, number]>
+
+function makeFillGeometry(hole: HolePolygon, y: number): BufferGeometry {
+  const contour2d = hole.map(([x, z]) => new Vector2(x, z))
+  const positions: number[] = []
+  const indices: number[] = []
+
+  for (const point of contour2d) {
+    positions.push(point.x, y, point.y)
+  }
+
+  const triangles = ShapeUtils.triangulateShape(contour2d, [])
+  for (const tri of triangles) {
+    indices.push(tri[0]!, tri[2]!, tri[1]!)
+  }
+
+  const geometry = new BufferGeometry()
+  geometry.setAttribute('position', new Float32BufferAttribute(positions, 3))
+  geometry.setIndex(indices)
+  geometry.computeVertexNormals()
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+function makeOutlineGeometry(hole: HolePolygon, y: number): BufferGeometry {
+  const positions: number[] = []
+
+  for (let index = 0; index < hole.length; index += 1) {
+    const [ax, az] = hole[index]!
+    const [bx, bz] = hole[(index + 1) % hole.length]!
+    positions.push(ax, y, az, bx, y, bz)
+  }
+
+  const geometry = new BufferGeometry()
+  geometry.setAttribute('position', new Float32BufferAttribute(positions, 3))
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+function makeHitGeometry(hole: HolePolygon, centerY: number, height: number): BufferGeometry {
+  let minX = Number.POSITIVE_INFINITY
+  let maxX = Number.NEGATIVE_INFINITY
+  let minZ = Number.POSITIVE_INFINITY
+  let maxZ = Number.NEGATIVE_INFINITY
+
+  for (const [x, z] of hole) {
+    minX = Math.min(minX, x)
+    maxX = Math.max(maxX, x)
+    minZ = Math.min(minZ, z)
+    maxZ = Math.max(maxZ, z)
+  }
+
+  const width = Math.max(maxX - minX + HIT_PADDING * 2, HIT_PADDING * 2)
+  const depth = Math.max(maxZ - minZ + HIT_PADDING * 2, HIT_PADDING * 2)
+  const centerX = (minX + maxX) / 2
+  const centerZ = (minZ + maxZ) / 2
+  const geometry = new BoxGeometry(width, height, depth)
+  geometry.translate(centerX, centerY, centerZ)
+  geometry.computeBoundingSphere()
+  return geometry
+}
+
+function getSurfaceY(slab: SlabNode): number {
+  const elevation = slab.elevation ?? 0.05
+  return (elevation > 0 ? elevation : 0) + SURFACE_OFFSET
+}
+
+function getHitCenterY(slab: SlabNode): number {
+  const elevation = slab.elevation ?? 0.05
+  const surfaceTop = elevation > 0 ? elevation : 0
+  // Keep the hit box's TOP at the slab surface (never poke above it) so the
+  // slab's centre thickness/height handle, which sits on top, always wins the
+  // raycast over the hole's selectable area.
+  return surfaceTop - getHitHeight(slab) / 2
+}
+
+function getHitHeight(slab: SlabNode): number {
+  return Math.max(Math.abs(slab.elevation ?? 0.05), MIN_HIT_HEIGHT)
+}
+
+function clearHoveredHoleIfMatches(nodeId: string, holeIndex: number) {
+  const { hoveredHole, setHoveredHole } = useEditor.getState()
+  if (hoveredHole?.nodeId === nodeId && hoveredHole.holeIndex === holeIndex) {
+    setHoveredHole(null)
+  }
+}
+
+function selectOwnedNode(ownerId: string, expectedType: 'stair' | 'elevator') {
+  const nodes = useScene.getState().nodes
+  const owner = nodes[ownerId as AnyNodeId]
+  if (owner?.type !== expectedType) return
+
+  const selectedId = owner.id as AnyNodeId
+
+  if (owner.type === 'elevator') {
+    const buildingId =
+      owner.parentId && nodes[owner.parentId as AnyNodeId]?.type === 'building'
+        ? (owner.parentId as BuildingNode['id'])
+        : null
+
+    useViewer
+      .getState()
+      .setSelection(
+        buildingId ? { buildingId, selectedIds: [selectedId] } : { selectedIds: [selectedId] },
+      )
+    return
+  }
+
+  const levelId = resolveLevelId(owner, nodes)
+  const buildingId =
+    levelId && levelId !== 'default' ? resolveBuildingForLevel(levelId as AnyNodeId, nodes) : null
+
+  useViewer.getState().setSelection({
+    ...(buildingId ? { buildingId: buildingId as BuildingNode['id'] } : {}),
+    ...(levelId && levelId !== 'default' ? { levelId: levelId as LevelNode['id'] } : {}),
+    selectedIds: [selectedId],
+  })
+}
+
+function resetPointerCursor() {
+  if (document.body.style.cursor === 'pointer') {
+    document.body.style.cursor = ''
+  }
+}
+
+function stopPointerPropagation(event: ThreeEvent<PointerEvent>) {
+  event.stopPropagation()
+  event.nativeEvent.stopPropagation()
+  event.nativeEvent.stopImmediatePropagation()
+}
+
+function suppressNodeClickUntilPointerUp() {
+  restoreNodeClickSuppression?.()
+  const previousInputDragging = useViewer.getState().inputDragging
+  useViewer.getState().setInputDragging(true)
+  swallowNextClick()
+
+  const restore = () => {
+    if (restoreNodeClickSuppression !== restore) return
+    useViewer.getState().setInputDragging(previousInputDragging)
+    window.removeEventListener('pointerup', restore)
+    window.removeEventListener('pointercancel', restore)
+    restoreNodeClickSuppression = null
+  }
+
+  restoreNodeClickSuppression = restore
+  window.addEventListener('pointerup', restore, { once: true })
+  window.addEventListener('pointercancel', restore, { once: true })
+}
+
+function releaseNodeClickSuppression() {
+  restoreNodeClickSuppression?.()
+}
+
+export function SlabHoleHighlights() {
+  const selectedIds = useViewer((state) => state.selection.selectedIds)
+  const hoveredHole = useEditor((state) => state.hoveredHole)
+  const setHoveredHole = useEditor((state) => state.setHoveredHole)
+
+  useEffect(() => {
+    if (hoveredHole && !selectedIds.includes(hoveredHole.nodeId as AnyNodeId)) {
+      setHoveredHole(null)
+    }
+  }, [hoveredHole, selectedIds, setHoveredHole])
+
+  if (selectedIds.length === 0) return null
+
+  return (
+    <>
+      {selectedIds.map((id) => (
+        <SelectedSlabHoleHighlights key={id} slabId={id} />
+      ))}
+    </>
+  )
+}
+
+function SelectedSlabHoleHighlights({ slabId }: { slabId: string }) {
+  const node = useScene((state) => state.nodes[slabId as AnyNodeId])
+  const override = useLiveNodeOverrides((state) => state.overrides.get(slabId))
+  const hoveredHole = useEditor((state) => state.hoveredHole)
+  const editingHole = useEditor((state) => state.editingHole)
+  const setHoveredHole = useEditor((state) => state.setHoveredHole)
+
+  const slab = node?.type === 'slab' ? (node as SlabNode) : null
+  const effectiveSlab = slab ? ({ ...slab, ...(override ?? {}) } as SlabNode) : null
+  const holes = effectiveSlab?.holes ?? []
+  const holeMetadata = effectiveSlab?.holeMetadata ?? []
+
+  // Portal the highlights into the slab's OWN object — exactly how
+  // NodeArrowHandles portals into a node object. This is what makes R3F deliver
+  // pointer events to the hit meshes (portaling into the raw scene renders but
+  // never receives hover/click), and the children inherit the slab's world
+  // transform so the holes sit in slab-local space with no manual math.
+  const [slabObject, setSlabObject] = useState<Object3D | null>(
+    () => sceneRegistry.nodes.get(slabId as AnyNodeId) ?? null,
+  )
+  useEffect(() => {
+    let frameId = 0
+    const resolve = () => {
+      const next = sceneRegistry.nodes.get(slabId as AnyNodeId) ?? null
+      setSlabObject((cur) => (cur === next ? cur : next))
+      if (!next) {
+        frameId = window.requestAnimationFrame(resolve)
+      }
+    }
+    resolve()
+    return () => {
+      if (frameId) window.cancelAnimationFrame(frameId)
+    }
+  }, [slabId])
+
+  useEffect(() => {
+    if (hoveredHole?.nodeId !== slabId) return
+    if (!effectiveSlab || hoveredHole.holeIndex >= holes.length) {
+      setHoveredHole(null)
+    }
+  }, [effectiveSlab, holes.length, hoveredHole, slabId, setHoveredHole])
+
+  if (!effectiveSlab || holes.length === 0 || !slabObject) return null
+
+  const surfaceY = getSurfaceY(effectiveSlab)
+  const hitCenterY = getHitCenterY(effectiveSlab)
+  const hitHeight = getHitHeight(effectiveSlab)
+
+  return createPortal(
+    <group>
+      {holes.map((hole, holeIndex) => {
+        const metadata = holeMetadata[holeIndex]
+        if (hole.length < 3) return null
+
+        const isActive =
+          (hoveredHole?.nodeId === slabId && hoveredHole.holeIndex === holeIndex) ||
+          (editingHole?.nodeId === slabId && editingHole.holeIndex === holeIndex)
+
+        return (
+          <SlabHoleHighlight
+            active={isActive}
+            hitCenterY={hitCenterY}
+            hitHeight={hitHeight}
+            hole={hole}
+            holeIndex={holeIndex}
+            key={`${slabId}:${holeIndex}`}
+            metadata={metadata}
+            slabId={slabId}
+            surfaceY={surfaceY}
+          />
+        )
+      })}
+    </group>,
+    slabObject,
+  )
+}
+
+function SlabHoleHighlight({
+  active,
+  hitCenterY,
+  hitHeight,
+  hole,
+  holeIndex,
+  metadata,
+  slabId,
+  surfaceY,
+}: {
+  active: boolean
+  hitCenterY: number
+  hitHeight: number
+  hole: HolePolygon
+  holeIndex: number
+  metadata: SurfaceHoleMetadata | undefined
+  slabId: string
+  surfaceY: number
+}) {
+  const fillGeometry = useMemo(() => makeFillGeometry(hole, surfaceY), [hole, surfaceY])
+  const outlineGeometry = useMemo(() => makeOutlineGeometry(hole, surfaceY), [hole, surfaceY])
+  const hitGeometry = useMemo(
+    () => makeHitGeometry(hole, hitCenterY, hitHeight),
+    [hitCenterY, hitHeight, hole],
+  )
+
+  useEffect(() => () => fillGeometry.dispose(), [fillGeometry])
+  useEffect(() => () => outlineGeometry.dispose(), [outlineGeometry])
+  useEffect(() => () => hitGeometry.dispose(), [hitGeometry])
+  useEffect(() => () => clearHoveredHoleIfMatches(slabId, holeIndex), [holeIndex, slabId])
+
+  const handlePointerEnter = useCallback(
+    (event: ThreeEvent<PointerEvent>) => {
+      event.stopPropagation()
+      useEditor.getState().setHoveredHole({ nodeId: slabId, holeIndex })
+      if (document.body.style.cursor !== 'pointer') {
+        document.body.style.cursor = 'pointer'
+      }
+    },
+    [holeIndex, slabId],
+  )
+
+  const handlePointerLeave = useCallback(
+    (event: ThreeEvent<PointerEvent>) => {
+      event.stopPropagation()
+      clearHoveredHoleIfMatches(slabId, holeIndex)
+      resetPointerCursor()
+    },
+    [holeIndex, slabId],
+  )
+
+  const handlePointerDown = useCallback(
+    (event: ThreeEvent<PointerEvent>) => {
+      if (event.button !== 0) return
+      stopPointerPropagation(event)
+      suppressNodeClickUntilPointerUp()
+      useEditor.getState().setHoveredHole({ nodeId: slabId, holeIndex })
+
+      // Auto-managed cutouts (stair / elevator) jump to their owner so the
+      // user edits the source rather than the synced hole. Everything else —
+      // manual holes and holes that predate holeMetadata — opens the editor.
+      if (metadata?.source === 'stair' && metadata.stairId) {
+        useEditor.getState().setEditingHole(null)
+        useEditor.getState().setHoveredHole(null)
+        resetPointerCursor()
+        selectOwnedNode(metadata.stairId, 'stair')
+        return
+      }
+      if (metadata?.source === 'elevator' && metadata.elevatorId) {
+        useEditor.getState().setEditingHole(null)
+        useEditor.getState().setHoveredHole(null)
+        resetPointerCursor()
+        selectOwnedNode(metadata.elevatorId, 'elevator')
+        return
+      }
+
+      useEditor.getState().setEditingHole({ nodeId: slabId, holeIndex })
+      useViewer.getState().setSelection({ selectedIds: [slabId as AnyNodeId] })
+    },
+    [holeIndex, metadata, slabId],
+  )
+
+  const handlePointerUp = useCallback((event: ThreeEvent<PointerEvent>) => {
+    releaseNodeClickSuppression()
+    stopPointerPropagation(event)
+  }, [])
+
+  return (
+    <>
+      <mesh
+        frustumCulled={false}
+        geometry={fillGeometry}
+        material={fillMaterial}
+        raycast={NO_RAYCAST}
+        renderOrder={1004}
+      />
+      <lineSegments
+        frustumCulled={false}
+        geometry={outlineGeometry}
+        material={outlineMaterial}
+        raycast={NO_RAYCAST}
+        renderOrder={1005}
+      />
+      {active && (
+        <>
+          <mesh
+            frustumCulled={false}
+            geometry={fillGeometry}
+            material={fillMaterial}
+            raycast={NO_RAYCAST}
+            renderOrder={1006}
+          />
+          <lineSegments
+            frustumCulled={false}
+            geometry={outlineGeometry}
+            material={outlineMaterial}
+            raycast={NO_RAYCAST}
+            renderOrder={1007}
+          />
+        </>
+      )}
+      <mesh
+        frustumCulled={false}
+        geometry={hitGeometry}
+        layers={EDITOR_LAYER}
+        material={hitMaterial}
+        onPointerDown={handlePointerDown}
+        onPointerEnter={handlePointerEnter}
+        onPointerLeave={handlePointerLeave}
+        onPointerUp={handlePointerUp}
+        renderOrder={1006}
+      />
+    </>
+  )
+}
+
+export default SlabHoleHighlights

packages/editor/src/components/editor/wall-move-side-handles.tsx

@@ -34,6 +34,13 @@ import { mergeGeometries } from 'three/examples/jsm/utils/BufferGeometryUtils.js
 import { MeshBasicNodeMaterial } from 'three/webgpu'
 import { sfxEmitter } from '../../lib/sfx-bus'
 import useEditor from '../../store/use-editor'
+import {
+  createArrowHitAreaGeometry,
+  createEndpointHitAreaGeometry,
+  InvisibleHandleHitArea,
+  NO_RAYCAST,
+  useInvisibleHitAreaMaterial,
+} from './node-arrow-handles'
 
 const HANDLE_OFFSET = 0.27
 const HANDLE_MIN_OFFSET = 0.33
@@ -227,7 +234,8 @@ function WallCornerLeaderHandle({ wall, endpoint }: { wall: WallNode; endpoint:
   const billboardRef = useRef<Group>(null)
   const parentWorldQuaternionRef = useRef(new Quaternion())
   const zoom = camera instanceof OrthographicCamera ? 1 / camera.zoom : 1
-  const scale = (isHovered ? 1.25 : 1) * zoom
+  const baseScale = zoom
+  const visualScale = isHovered ? 1.25 : 1
 
   const corner = endpoint === 'start' ? wall.start : wall.end
   const x = corner[0]
@@ -235,7 +243,10 @@ function WallCornerLeaderHandle({ wall, endpoint }: { wall: WallNode; endpoint:
   const wallHeight = wall.height ?? DEFAULT_WALL_HEIGHT
 
   const dashedGeometry = useMemo(() => buildDashedVerticalGeometry(wallHeight), [wallHeight])
+  const hitGeometry = useMemo(() => createEndpointHitAreaGeometry(CORNER_HEX_RADIUS), [])
+  const hitMaterial = useInvisibleHitAreaMaterial()
   useEffect(() => () => dashedGeometry.dispose(), [dashedGeometry])
+  useEffect(() => () => hitGeometry.dispose(), [hitGeometry])
 
   // Node materials matched to the rest of the file — mixing plain
   // `meshBasicMaterial` with WebGPU node materials trips
@@ -332,9 +343,10 @@ function WallCornerLeaderHandle({ wall, endpoint }: { wall: WallNode; endpoint:
         position={[x, 0, z]}
         renderOrder={1001}
       />
-      <group position={[x, CORNER_FLOOR_OFFSET, z]} ref={billboardRef} scale={scale}>
-        <mesh
-          material={hexMaterial}
+      <group position={[x, CORNER_FLOOR_OFFSET, z]} ref={billboardRef} scale={baseScale}>
+        <InvisibleHandleHitArea
+          geometry={hitGeometry}
+          material={hitMaterial}
           onPointerDown={activateEndpointMove}
           onPointerEnter={(event) => {
             event.stopPropagation()
@@ -348,14 +360,17 @@ function WallCornerLeaderHandle({ wall, endpoint }: { wall: WallNode; endpoint:
               document.body.style.cursor = ''
             }
           }}
-          renderOrder={1003}
-        >
+          scale={1}
+        />
+        <group scale={visualScale}>
+          <mesh material={hexMaterial} raycast={NO_RAYCAST} renderOrder={1003}>
             <circleGeometry args={[CORNER_HEX_RADIUS, 6]} />
           </mesh>
-        <mesh material={ringMaterial} renderOrder={1002}>
+          <mesh material={ringMaterial} raycast={NO_RAYCAST} renderOrder={1002}>
             <ringGeometry args={[CORNER_HEX_RADIUS, CORNER_HEX_RADIUS * 1.18, 6]} />
           </mesh>
         </group>
+      </group>
     </>
   )
 }
@@ -363,6 +378,8 @@ function WallCornerLeaderHandle({ wall, endpoint }: { wall: WallNode; endpoint:
 function WallHeightArrowHandle({ wall }: { wall: WallNode }) {
   const [isHovered, setIsHovered] = useState(false)
   const arrowGeometry = useMemo(() => createArrowHandleGeometry(), [])
+  const hitGeometry = useMemo(() => createArrowHitAreaGeometry(), [])
+  const hitMaterial = useInvisibleHitAreaMaterial()
   const arrowMaterial = useMemo(
     () =>
       new MeshBasicNodeMaterial({
@@ -377,7 +394,8 @@ function WallHeightArrowHandle({ wall }: { wall: WallNode }) {
   )
   const { camera, raycaster, gl } = useThree()
   const zoom = camera instanceof OrthographicCamera ? 1 / camera.zoom : 1
-  const scale = (isHovered ? 1.12 : 1) * zoom * ARROW_SCALE
+  const baseScale = zoom * ARROW_SCALE
+  const scale = (isHovered ? 1.12 : 1) * baseScale
   const dragCleanupRef = useRef<(() => void) | null>(null)
 
   useEffect(() => {
@@ -394,6 +412,7 @@ function WallHeightArrowHandle({ wall }: { wall: WallNode }) {
   }, [])
 
   useEffect(() => () => arrowGeometry.dispose(), [arrowGeometry])
+  useEffect(() => () => hitGeometry.dispose(), [hitGeometry])
   useEffect(() => () => arrowMaterial.dispose(), [arrowMaterial])
 
   // Sit on the visual centre of the wall — for curved walls that's the
@@ -509,12 +528,10 @@ function WallHeightArrowHandle({ wall }: { wall: WallNode }) {
 
   return (
     <group position={[midX, handleY, midZ]} rotation={[0, wallAngle, 0]}>
-      <group rotation={[0, Math.PI / 2, Math.PI / 2]} scale={scale}>
-        <mesh
-          // Geometry-as-prop + frustumCulled={false} — see WallMoveArrowHandle.
-          frustumCulled={false}
-          geometry={arrowGeometry}
-          material={arrowMaterial}
+      <group rotation={[0, Math.PI / 2, Math.PI / 2]}>
+        <InvisibleHandleHitArea
+          geometry={hitGeometry}
+          material={hitMaterial}
           onPointerDown={activateHeightResize}
           onPointerEnter={(event) => {
             event.stopPropagation()
@@ -528,7 +545,16 @@ function WallHeightArrowHandle({ wall }: { wall: WallNode }) {
               document.body.style.cursor = ''
             }
           }}
+          scale={baseScale}
+        />
+        <mesh
+          // Geometry-as-prop + frustumCulled={false} — see WallMoveArrowHandle.
+          frustumCulled={false}
+          geometry={arrowGeometry}
+          material={arrowMaterial}
+          raycast={NO_RAYCAST}
           renderOrder={1002}
+          scale={scale}
         />
       </group>
     </group>
@@ -538,6 +564,8 @@ function WallHeightArrowHandle({ wall }: { wall: WallNode }) {
 function WallMoveArrowHandle({ wall, handle }: { wall: WallNode; handle: WallMoveHandle }) {
   const [isHovered, setIsHovered] = useState(false)
   const arrowGeometry = useMemo(() => createArrowHandleGeometry(), [])
+  const hitGeometry = useMemo(() => createArrowHitAreaGeometry(), [])
+  const hitMaterial = useInvisibleHitAreaMaterial()
   const arrowMaterial = useMemo(
     () =>
       new MeshBasicNodeMaterial({
@@ -554,7 +582,8 @@ function WallMoveArrowHandle({ wall, handle }: { wall: WallNode; handle: WallMov
 
   const zoom = camera instanceof OrthographicCamera ? 1 / camera.zoom : 1
 
-  const scale = (isHovered ? 1.12 : 1) * zoom * ARROW_SCALE
+  const baseScale = zoom * ARROW_SCALE
+  const scale = (isHovered ? 1.12 : 1) * baseScale
 
   useEffect(() => {
     arrowMaterial.color.set(isHovered ? ARROW_HOVER_COLOR : ARROW_COLOR)
@@ -569,6 +598,7 @@ function WallMoveArrowHandle({ wall, handle }: { wall: WallNode; handle: WallMov
   }, [])
 
   useEffect(() => () => arrowGeometry.dispose(), [arrowGeometry])
+  useEffect(() => () => hitGeometry.dispose(), [hitGeometry])
   useEffect(() => () => arrowMaterial.dispose(), [arrowMaterial])
 
   const activateWallMove = (event: ThreeEvent<PointerEvent>) => {
@@ -586,16 +616,10 @@ function WallMoveArrowHandle({ wall, handle }: { wall: WallNode; handle: WallMov
   }
 
   return (
-    <group position={handle.position} rotation={[0, handle.rotationY, 0]} scale={scale}>
-      <mesh
-        // Pass geometry as a prop (not `<primitive attach="geometry">`)
-        // so the mesh is never rendered with R3F's default empty
-        // `BufferGeometry`. Combined with `frustumCulled={false}`, the
-        // primitive-attach path emits a `Draw(0, 1, 0, 0)` on the first
-        // frame and WebGPU flags "Vertex buffer slot 0 ... was not set".
-        frustumCulled={false}
-        geometry={arrowGeometry}
-        material={arrowMaterial}
+    <group position={handle.position} rotation={[0, handle.rotationY, 0]}>
+      <InvisibleHandleHitArea
+        geometry={hitGeometry}
+        material={hitMaterial}
         onPointerDown={activateWallMove}
         onPointerEnter={(event) => {
           event.stopPropagation()
@@ -609,7 +633,20 @@ function WallMoveArrowHandle({ wall, handle }: { wall: WallNode; handle: WallMov
             document.body.style.cursor = ''
           }
         }}
+        scale={baseScale}
+      />
+      <mesh
+        // Pass geometry as a prop (not `<primitive attach="geometry">`)
+        // so the mesh is never rendered with R3F's default empty
+        // `BufferGeometry`. Combined with `frustumCulled={false}`, the
+        // primitive-attach path emits a `Draw(0, 1, 0, 0)` on the first
+        // frame and WebGPU flags "Vertex buffer slot 0 ... was not set".
+        frustumCulled={false}
+        geometry={arrowGeometry}
+        material={arrowMaterial}
+        raycast={NO_RAYCAST}
         renderOrder={1002}
+        scale={scale}
       />
     </group>
   )
@@ -618,6 +655,8 @@ function WallMoveArrowHandle({ wall, handle }: { wall: WallNode; handle: WallMov
 function FenceMoveArrowHandle({ fence, handle }: { fence: FenceNode; handle: WallMoveHandle }) {
   const [isHovered, setIsHovered] = useState(false)
   const arrowGeometry = useMemo(() => createArrowHandleGeometry(), [])
+  const hitGeometry = useMemo(() => createArrowHitAreaGeometry(), [])
+  const hitMaterial = useInvisibleHitAreaMaterial()
   const arrowMaterial = useMemo(
     () =>
       new MeshBasicNodeMaterial({
@@ -633,7 +672,8 @@ function FenceMoveArrowHandle({ fence, handle }: { fence: FenceNode; handle: Wal
   const { camera } = useThree()
 
   const zoom = camera instanceof OrthographicCamera ? 1 / camera.zoom : 1
-  const scale = (isHovered ? 1.12 : 1) * zoom * ARROW_SCALE
+  const baseScale = zoom * ARROW_SCALE
+  const scale = (isHovered ? 1.12 : 1) * baseScale
 
   useEffect(() => {
     arrowMaterial.color.set(isHovered ? ARROW_HOVER_COLOR : ARROW_COLOR)
@@ -648,6 +688,7 @@ function FenceMoveArrowHandle({ fence, handle }: { fence: FenceNode; handle: Wal
   }, [])
 
   useEffect(() => () => arrowGeometry.dispose(), [arrowGeometry])
+  useEffect(() => () => hitGeometry.dispose(), [hitGeometry])
   useEffect(() => () => arrowMaterial.dispose(), [arrowMaterial])
 
   const activateFenceMove = (event: ThreeEvent<PointerEvent>) => {
@@ -664,13 +705,10 @@ function FenceMoveArrowHandle({ fence, handle }: { fence: FenceNode; handle: Wal
   }
 
   return (
-    <group position={handle.position} rotation={[0, handle.rotationY, 0]} scale={scale}>
-      <mesh
-        // Pass geometry as a prop — see WallMoveArrowHandle for the
-        // WebGPU "Vertex buffer slot 0 ... was not set" rationale.
-        frustumCulled={false}
-        geometry={arrowGeometry}
-        material={arrowMaterial}
+    <group position={handle.position} rotation={[0, handle.rotationY, 0]}>
+      <InvisibleHandleHitArea
+        geometry={hitGeometry}
+        material={hitMaterial}
         onPointerDown={activateFenceMove}
         onPointerEnter={(event) => {
           event.stopPropagation()
@@ -684,7 +722,17 @@ function FenceMoveArrowHandle({ fence, handle }: { fence: FenceNode; handle: Wal
             document.body.style.cursor = ''
           }
         }}
+        scale={baseScale}
+      />
+      <mesh
+        // Pass geometry as a prop — see WallMoveArrowHandle for the
+        // WebGPU "Vertex buffer slot 0 ... was not set" rationale.
+        frustumCulled={false}
+        geometry={arrowGeometry}
+        material={arrowMaterial}
+        raycast={NO_RAYCAST}
         renderOrder={1002}
+        scale={scale}
       />
     </group>
   )

packages/editor/src/components/tools/item/placement-strategies.ts

@@ -103,12 +103,13 @@ export const floorStrategy = {
     // building-local ToolManager group, so local coords are correct for both data and visuals.
     const x = snapToGrid(event.localPosition[0], swapDims ? dimZ : dimX)
     const z = snapToGrid(event.localPosition[2], swapDims ? dimX : dimZ)
+    const y = ctx.gridPosition.y
 
     return {
-      gridPosition: [x, 0, z],
-      cursorPosition: [x, event.localPosition[1], z],
+      gridPosition: [x, y, z],
+      cursorPosition: [x, y, z],
       cursorRotationY: rotY,
-      nodeUpdate: { position: [x, 0, z] },
+      nodeUpdate: { position: [x, y, z] },
       stopPropagation: false,
       dirtyNodeId: null,
     }
@@ -126,7 +127,11 @@ export const floorStrategy = {
     if (ctx.state.surface !== 'floor') return null
     if (!(ctx.levelId && ctx.draftItem)) return null
 
-    const pos: [number, number, number] = [ctx.gridPosition.x, 0, ctx.gridPosition.z]
+    const pos: [number, number, number] = [
+      ctx.gridPosition.x,
+      ctx.gridPosition.y,
+      ctx.gridPosition.z,
+    ]
     const valid = validators.canPlaceOnFloor(
       ctx.levelId,
       pos,
@@ -793,7 +798,7 @@ export function checkCanPlace(ctx: PlacementContext, validators: SpatialValidato
   // Floor (no attachTo)
   return validators.canPlaceOnFloor(
     ctx.levelId,
-    [ctx.gridPosition.x, 0, ctx.gridPosition.z],
+    [ctx.gridPosition.x, ctx.gridPosition.y, ctx.gridPosition.z],
     alignedDims,
     ctx.draftItem.rotation,
     [ctx.draftItem.id],

packages/editor/src/components/tools/item/use-placement-coordinator.tsx

@@ -1,4 +1,4 @@
-import type { AssetInput } from '@pascal-app/core'
+import type { AssetInput, ItemNode } from '@pascal-app/core'
 import {
   type AlignmentAnchor,
   type AnyNode,
@@ -14,7 +14,6 @@ import {
   resolveLevelId,
   type ShelfEvent,
   sceneRegistry,
-  spatialGridManager,
   useAlignmentGuides,
   useLiveTransforms,
   useScene,
@@ -44,6 +43,7 @@ import { LineBasicNodeMaterial, MeshBasicNodeMaterial } from 'three/webgpu'
 import { EDITOR_LAYER } from '../../../lib/constants'
 import { sfxEmitter } from '../../../lib/sfx-bus'
 import useEditor from '../../../store/use-editor'
+import { getFloorStackPreviewPosition } from '../shared/floor-stack-preview'
 import {
   createLineGeometry,
   getBoxEdgePoints,
@@ -141,6 +141,22 @@ function getFallbackPreviewBounds(
   }
 }
 
+function getGridAlignedPreviewNode(item: ItemNode): ItemNode {
+  const scaled = getScaledDimensions(item)
+  const aligned = getGridAlignedDimensions(scaled, item.asset.attachTo)
+  if (scaled[0] === aligned[0] && scaled[1] === aligned[1] && scaled[2] === aligned[2]) {
+    return item
+  }
+
+  const scaleAxis = (axis: 0 | 1 | 2) =>
+    scaled[axis] === 0 ? item.scale[axis] : item.scale[axis] * (aligned[axis] / scaled[axis])
+
+  return {
+    ...item,
+    scale: [scaleAxis(0), scaleAxis(1), scaleAxis(2)] as [number, number, number],
+  }
+}
+
 // Shared materials for placement cursor - we just change colors, not swap materials
 // Note: EdgesGeometry doesn't work with dashed lines, so using solid lines
 const edgeMaterial = new LineBasicNodeMaterial({
@@ -359,6 +375,23 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
     applyPoints(measurementHeightRef, heightPoints)
   }, [])
 
+  const getFloorVisualPosition = useCallback(
+    (
+      position: [number, number, number],
+      nodeUpdate?: Partial<ItemNode>,
+    ): [number, number, number] => {
+      const draft = draftNode.current
+      if (!(draft && !asset?.attachTo)) return position
+      const previewNode = getGridAlignedPreviewNode({ ...draft, ...nodeUpdate } as ItemNode)
+      return getFloorStackPreviewPosition({
+        node: previewNode,
+        position,
+        rotation: previewNode.rotation,
+      })
+    },
+    [asset?.attachTo, draftNode],
+  )
+
   useEffect(() => {
     if (!asset) return
     useScene.temporal.getState().pause()
@@ -661,11 +694,6 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
         result.gridPosition[1],
         result.gridPosition[2] + alignZ,
       ]
-      const cursorPos: [number, number, number] = [
-        result.cursorPosition[0] + alignX,
-        result.cursorPosition[1],
-        result.cursorPosition[2] + alignZ,
-      ]
 
       // Play snap sound when grid position changes
       if (
@@ -677,7 +705,8 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
 
       previousGridPos = [...gridPos]
       gridPosition.current.set(...gridPos)
-      cursorGroupRef.current.position.set(cursorPos[0], cursorPos[1], cursorPos[2])
+      const cursorPosition = getFloorVisualPosition(gridPos)
+      cursorGroupRef.current.position.set(cursorPosition[0], cursorPosition[1], cursorPosition[2])
       // Floor items only rotate on Y; keep the preview box (and the live
       // transform the 2D floorplan mirrors) aligned with the draft's
       // rotation. Without this the box stays at its seed rotation until a
@@ -946,8 +975,13 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
         shelfId: null,
       })
       gridPosition.current.set(wx, 0, wz)
+      const levelId = useViewer.getState().selection.levelId as AnyNodeId | null
+      const floorVisualPosition = getFloorVisualPosition(
+        floorPos,
+        levelId ? { parentId: levelId } : undefined,
+      )
       if (cursorGroupRef.current) {
-        cursorGroupRef.current.position.set(wx, 0, wz)
+        cursorGroupRef.current.position.set(...floorVisualPosition)
       }
 
       const draft = draftNode.current
@@ -1466,12 +1500,21 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
           gridPosition.current.set(x, gridPosition.current.y, z)
           draft.position = [x, gridPosition.current.y, z]
           if (cursorGroupRef.current) {
+            if (surface === 'floor') {
+              cursorGroupRef.current.position.set(
+                ...getFloorVisualPosition([x, gridPosition.current.y, z]),
+              )
+            } else {
               cursorGroupRef.current.position.x = x
               cursorGroupRef.current.position.z = z
             }
+          }
           if (mesh) {
             mesh.position.x = x
             mesh.position.z = z
+            if (surface === 'floor') {
+              mesh.position.y = getFloorVisualPosition([x, gridPosition.current.y, z])[1]
+            }
           }
         } else if (surface === 'item-surface' && placementState.current.surfaceItemId) {
           const surfaceMesh = sceneRegistry.nodes.get(placementState.current.surfaceItemId)
@@ -1501,7 +1544,10 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
         // Update live transform for 2D floorplan with post-snap position
         const currentLive = useLiveTransforms.getState().get(draft.id)
         if (currentLive) {
-          const livePosition: [number, number, number] = cursorGroupRef.current
+          const livePosition: [number, number, number] =
+            surface === 'floor'
+              ? [draft.position[0], draft.position[1], draft.position[2]]
+              : cursorGroupRef.current
                 ? [
                     cursorGroupRef.current.position.x,
                     cursorGroupRef.current.position.y,
@@ -1647,6 +1693,7 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
     canPlaceOnWall,
     canPlaceOnCeiling,
     draftNode,
+    getFloorVisualPosition,
     gridSnapStep,
     updateDimensionGuides,
     updatePreviewGeometry,
@@ -1747,18 +1794,13 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
 
       // Adjust Y for slab elevation (floor items on top of slabs)
       if (!asset.attachTo) {
-        const nodes = useScene.getState().nodes
-        const levelId = resolveLevelId(draftNode.current, nodes)
-        const slabElevation = spatialGridManager.getSlabElevationForItem(
-          levelId,
-          [gridPosition.current.x, gridPosition.current.y, gridPosition.current.z],
-          getGridAlignedDimensions(
-            getScaledDimensions(draftNode.current),
-            draftNode.current.asset.attachTo,
-          ),
-          draftNode.current.rotation,
-        )
-        mesh.position.y = slabElevation
+        const visualPosition = getFloorVisualPosition([
+          gridPosition.current.x,
+          gridPosition.current.y,
+          gridPosition.current.z,
+        ])
+        mesh.position.y = visualPosition[1]
+        cursorGroupRef.current.position.y = visualPosition[1]
       }
     }
   })

packages/editor/src/components/tools/registry/move-registry-node-tool.tsx

@@ -25,6 +25,7 @@ import { markToolCancelConsumed } from '../../../hooks/use-keyboard'
 import { sfxEmitter } from '../../../lib/sfx-bus'
 import useEditor from '../../../store/use-editor'
 import { CursorSphere } from '../shared/cursor-sphere'
+import { getFloorStackPreviewPosition } from '../shared/floor-stack-preview'
 import { PlacementBox } from '../shared/placement-box'
 
 /** Snap a world-plan coordinate to the editor's active grid step (0.5 / 0.25
@@ -174,11 +175,34 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
     // fresh clone after a drop, or the user picks a different catalog tile —
     // and `useState` only honours its initial value, so without this the box
     // would keep the previous clone's rotation/position until the next R/T.
-    setCursorPosition(originalPosition)
     setCursorRotationY(originalRotationY)
     lastCursorRef.current = originalPosition
     let committed = false
 
+    const baseRotation = (node as { rotation?: unknown }).rotation
+    const toCommitRotation = (y: number): number | [number, number, number] =>
+      Array.isArray(baseRotation)
+        ? [(baseRotation[0] as number) ?? 0, y, (baseRotation[2] as number) ?? 0]
+        : y
+
+    const getVisualPosition = (
+      position: [number, number, number],
+      rotationY = rotationRef.current,
+    ): [number, number, number] => {
+      return getFloorStackPreviewPosition({
+        node,
+        position,
+        rotation: toCommitRotation(rotationY),
+      })
+    }
+    const markMovedNodeDirty = () => {
+      if (useScene.getState().nodes[node.id]) {
+        useScene.getState().markDirty(node.id as AnyNodeId)
+      }
+    }
+
+    setCursorPosition(getVisualPosition(originalPosition, originalRotationY))
+
     // Re-run the floor-collision check at the live cursor + rotation and push
     // the result to the box colour. Shift forces a valid (green) override so
     // the user can drop on top of an existing item on purpose. Only shelves
@@ -196,10 +220,10 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
         setValid(true)
         return
       }
-      const [x, , z] = lastCursorRef.current
+      const [x, y, z] = lastCursorRef.current
       const { valid: placeable } = spatialGridManager.canPlaceOnFloor(
         levelId,
-        [x, 0, z],
+        [x, y, z],
         boxDimensions,
         [0, rotationRef.current, 0],
         [node.id],
@@ -209,14 +233,6 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
     }
     recomputeValidity()
 
-    // The node's rotation shape (tuple vs scalar) is preserved on commit;
-    // only the Y angle changes. Most registry kinds use a `[x, y, z]` tuple.
-    const baseRotation = (node as { rotation?: unknown }).rotation
-    const toCommitRotation = (y: number): number | [number, number, number] =>
-      Array.isArray(baseRotation)
-        ? [(baseRotation[0] as number) ?? 0, y, (baseRotation[2] as number) ?? 0]
-        : y
-
     // Disable raycast on the moved node's meshes for the duration of
     // the drag. As the shelf follows the cursor, the cursor ray would
     // otherwise hit the moved mesh first → only `${kind}:move` fires →
@@ -275,13 +291,15 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
         useAlignmentGuides.getState().clear()
       }
 
+      const position: [number, number, number] = [x, originalPosition[1], z]
+      const visualPosition = getVisualPosition(position)
       hasMovedRef.current = true
-      setCursorPosition([x, 0, z])
-      lastCursorRef.current = [x, 0, z]
+      setCursorPosition(visualPosition)
+      lastCursorRef.current = position
       recomputeValidity()
 
       // Pure imperative: move the mesh via its registered Object3D ref.
-      sceneRegistry.nodes.get(node.id)?.position.set(x, 0, z)
+      sceneRegistry.nodes.get(node.id)?.position.set(...visualPosition)
       // Publish to `useLiveTransforms` so the 2D floor plan can mirror
       // the drag in real-time (the floor-plan layer subscribes to this
       // store and overrides the node's rendered position when an entry
@@ -293,9 +311,10 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
       // (slab / ceiling / fence) follow a different delta contract —
       // their floor-plan move-targets handle the override themselves.
       useLiveTransforms.getState().set(node.id, {
-        position: [x, 0, z],
+        position,
         rotation: rotationRef.current,
       })
+      markMovedNodeDirty()
 
       const prev = previousSnapRef.current
       if (!prev || prev[0] !== x || prev[1] !== z) {
@@ -331,6 +350,7 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
       const position: [number, number, number] = [...lastCursorRef.current]
 
       const rotation = toCommitRotation(rotationRef.current)
+      const visualPosition = getVisualPosition(position)
 
       if (useScene.getState().nodes[node.id]) {
         useScene.temporal.getState().resume()
@@ -355,18 +375,16 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
         }
       }
 
-      // Keep mesh.position/rotation aligned with the just-committed scene
-      // values so the next R3F frame paints correctly even if React's
-      // reconciliation lags by a tick.
+      // Clear after the scene write so React reconciles against the new
+      // canonical position, then restamp the lifted presentation Y for the
+      // current frame.
+      useLiveTransforms.getState().clear(node.id)
       const mesh = sceneRegistry.nodes.get(node.id)
       if (mesh) {
-        mesh.position.set(position[0], position[1], position[2])
+        mesh.position.set(...visualPosition)
         mesh.rotation.y = rotationRef.current
       }
 
-      // Now safe to clear — node.position is already the new value, so
-      // `ParametricNodeRenderer`'s next render lands at `[x, 0, z]`.
-      useLiveTransforms.getState().clear(node.id)
       useAlignmentGuides.getState().clear()
 
       sfxEmitter.emit('sfx:item-place')
@@ -405,12 +423,19 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
       sfxEmitter.emit('sfx:item-rotate')
       rotationRef.current += delta
       setCursorRotationY(rotationRef.current)
+      const position = lastCursorRef.current
+      const visualPosition = getVisualPosition(position)
+      setCursorPosition(visualPosition)
       const m = sceneRegistry.nodes.get(node.id)
-      if (m) m.rotation.y = rotationRef.current
+      if (m) {
+        m.position.set(...visualPosition)
+        m.rotation.y = rotationRef.current
+      }
       useLiveTransforms.getState().set(node.id, {
-        position: lastCursorRef.current,
+        position,
         rotation: rotationRef.current,
       })
+      markMovedNodeDirty()
       // Rotation changes the footprint's collision span — re-check validity.
       recomputeValidity()
     }
@@ -437,13 +462,14 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
     }
 
     const onCancel = () => {
+      useLiveTransforms.getState().clear(node.id)
       const m = sceneRegistry.nodes.get(node.id)
       if (m) {
-        m.position.set(originalPosition[0], originalPosition[1], originalPosition[2])
+        m.position.set(...getVisualPosition(originalPosition, originalRotationY))
         m.rotation.y = originalRotationY
       }
-      useLiveTransforms.getState().clear(node.id)
       useAlignmentGuides.getState().clear()
+      markMovedNodeDirty()
       useScene.temporal.getState().resume()
       markToolCancelConsumed()
       exitMoveMode()
@@ -467,10 +493,11 @@ export function MoveRegistryNodeTool({ node }: { node: AnyNode }) {
       // unmount / commit paths uniformly.
       useAlignmentGuides.getState().clear()
       if (!committed) {
+        useLiveTransforms.getState().clear(node.id)
         sceneRegistry.nodes
           .get(node.id)
-          ?.position.set(originalPosition[0], originalPosition[1], originalPosition[2])
-        useLiveTransforms.getState().clear(node.id)
+          ?.position.set(...getVisualPosition(originalPosition, originalRotationY))
+        markMovedNodeDirty()
         useScene.temporal.getState().resume()
       }
     }

packages/editor/src/components/tools/shared/floor-stack-preview.ts

@@ -0,0 +1,25 @@
+import { type AnyNode, type AnyNodeId, getFloorStackedPosition, useScene } from '@pascal-app/core'
+
+type FloorStackPreviewArgs = {
+  node: AnyNode
+  position: [number, number, number]
+  rotation?: unknown
+  levelId?: string | null
+  nodes?: Record<AnyNodeId, AnyNode>
+}
+
+export function getFloorStackPreviewPosition({
+  node,
+  position,
+  rotation,
+  levelId,
+  nodes,
+}: FloorStackPreviewArgs): [number, number, number] {
+  return getFloorStackedPosition({
+    node,
+    nodes: nodes ?? useScene.getState().nodes,
+    position,
+    rotation,
+    levelId,
+  })
+}

packages/editor/src/components/tools/shared/polygon-editor.tsx

@@ -11,16 +11,17 @@ import {
   type Line,
   type Object3D,
   Shape,
-  SphereGeometry,
 } from 'three'
 import { MeshBasicNodeMaterial } from 'three/webgpu'
 import { EDITOR_LAYER } from '../../../lib/constants'
 import { sfxEmitter } from '../../../lib/sfx-bus'
 import {
+  createMoveCrossHandleGeometry,
   ARROW_COLOR as EDGE_ARROW_COLOR,
   ARROW_HOVER_COLOR as EDGE_ARROW_HOVER_COLOR,
   ARROW_SCALE as EDGE_ARROW_SCALE,
   useArrowMaterial,
+  useInvisibleHitAreaMaterial,
 } from '../../editor/node-arrow-handles'
 import { snapToHalf } from '../item/placement-math'
 
@@ -185,7 +186,11 @@ function OutlinedCylinderHandle({
   )
 }
 
-function OutlinedSphereHandle({
+// Whole-polygon move grip — the generic 4-way cross-arrow (matching the node
+// move handles) with an invisible cylinder hit area, replacing the old sphere.
+// The cross sits on SCENE_LAYER (so the ink pass outlines it) while the
+// cylinder hit mesh is on EDITOR_LAYER (grabbable, out of the MRT scene pass).
+function OutlinedCrossHandle({
   color,
   position,
   ...handlers
@@ -193,20 +198,33 @@ function OutlinedSphereHandle({
   color: string
   position: [number, number, number]
 } & HandleHandlers) {
-  const geometry = useMemo(() => new SphereGeometry(0.09, 20, 20), [])
+  const geometry = useMemo(() => createMoveCrossHandleGeometry(), [])
   const material = usePolygonNodeMaterial(color)
+  const hitGeometry = useMemo(() => new CylinderGeometry(0.24, 0.24, 0.18, 24), [])
+  const hitMaterial = useInvisibleHitAreaMaterial()
   useEffect(() => () => geometry.dispose(), [geometry])
+  useEffect(() => () => hitGeometry.dispose(), [hitGeometry])
 
   return (
+    <group position={position}>
       <mesh
         frustumCulled={false}
         geometry={geometry}
         layers={SCENE_LAYER}
         material={material}
-      position={position}
+        raycast={NO_RAYCAST}
         renderOrder={1010}
+        scale={EDGE_ARROW_SCALE}
+      />
+      <mesh
+        frustumCulled={false}
+        geometry={hitGeometry}
+        layers={EDITOR_LAYER}
+        material={hitMaterial}
+        renderOrder={1011}
         {...handlers}
       />
+    </group>
   )
 }
 
@@ -651,7 +669,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
 
         return (
           <OutlinedCylinderHandle
-            color={isDragging ? '#22c55e' : isHovered ? '#60a5fa' : '#3b82f6'}
+            color={isDragging || isHovered ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
             height={height}
             key={`vertex-${index}`}
             onClick={(e) => {
@@ -693,8 +711,8 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
       })}
 
       {allowPolygonMove && (
-        <OutlinedSphereHandle
-          color={dragState?.mode === 'polygon' ? '#22c55e' : '#f59e0b'}
+        <OutlinedCrossHandle
+          color={dragState?.mode === 'polygon' ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
           onClick={(e) => {
             if (e.button !== 0) return
             e.stopPropagation()
@@ -760,7 +778,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
               >
                 <boxGeometry args={[length, EDGE_HANDLE_HEIGHT, EDGE_HANDLE_THICKNESS]} />
                 <meshBasicMaterial
-                  color={isDragging ? '#22c55e' : '#60a5fa'}
+                  color={isDragging ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
                   opacity={isDragging ? 0.5 : isHovered ? 0.38 : 0.14}
                   transparent
                 />
@@ -769,9 +787,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
                   Points outward from the edge; dragging it translates only this
                   edge's two vertices along the outward normal. */}
               <OutlinedEdgeArrowHandle
-                color={
-                  isDragging ? '#22c55e' : isHovered ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR
-                }
+                color={isDragging || isHovered ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
                 geometry={arrowGeometry}
                 onClick={(e) => {
                   if (e.button !== 0) return
@@ -807,7 +823,7 @@ export const PolygonEditor: React.FC<PolygonEditorProps> = ({
 
           return (
             <OutlinedCylinderHandle
-              color={isHovered ? '#4ade80' : '#22c55e'}
+              color={isHovered ? EDGE_ARROW_HOVER_COLOR : EDGE_ARROW_COLOR}
               height={height}
               key={`midpoint-${index}`}
               onClick={(e) => {

packages/editor/src/components/tools/stair/stair-tool.tsx

@@ -14,6 +14,7 @@ import { useEffect, useMemo, useRef } from 'react'
 import * as THREE from 'three'
 import { sfxEmitter } from '../../../lib/sfx-bus'
 import { CursorSphere } from '../shared/cursor-sphere'
+import { getFloorStackPreviewPosition } from '../shared/floor-stack-preview'
 import {
   DEFAULT_CURVED_STAIR_INNER_RADIUS,
   DEFAULT_CURVED_STAIR_SWEEP_ANGLE,
@@ -73,19 +74,10 @@ function createStairPreviewGeometry(): THREE.BufferGeometry {
 }
 
 /**
- * Creates a stair group with one default stair segment at the given position/rotation.
+ * Creates a default straight stair segment.
  */
-function commitStairPlacement(
-  levelId: LevelNode['id'],
-  position: [number, number, number],
-  rotation: number,
-): void {
-  const { createNodes, nodes } = useScene.getState()
-
-  const stairCount = Object.values(nodes).filter((n) => n.type === 'stair').length
-  const name = `Staircase ${stairCount + 1}`
-
-  const segment = StairSegmentNode.parse({
+function createDefaultStairSegment() {
+  return StairSegmentNode.parse({
     segmentType: 'stair',
     width: DEFAULT_STAIR_WIDTH,
     length: DEFAULT_STAIR_LENGTH,
@@ -96,14 +88,24 @@ function commitStairPlacement(
     thickness: DEFAULT_STAIR_THICKNESS,
     position: [0, 0, 0],
   })
+}
 
-  const sortedLevels = Object.values(nodes)
-    .filter((node): node is LevelNode => node.type === 'level')
-    .sort((left, right) => left.level - right.level)
-  const currentLevelIndex = sortedLevels.findIndex((level) => level.id === levelId)
-  const nextLevelId = sortedLevels[currentLevelIndex + 1]?.id ?? levelId
-
-  const stair = StairNode.parse({
+function createDefaultStairNode({
+  name,
+  levelId,
+  nextLevelId,
+  position,
+  rotation,
+  segmentId,
+}: {
+  name: string
+  levelId: LevelNode['id']
+  nextLevelId: LevelNode['id']
+  position: [number, number, number]
+  rotation: number
+  segmentId: StairSegmentNode['id']
+}) {
+  return StairNode.parse({
     name,
     position,
     rotation,
@@ -125,7 +127,37 @@ function commitStairPlacement(
     showStepSupports: DEFAULT_SPIRAL_SHOW_STEP_SUPPORTS,
     railingHeight: DEFAULT_STAIR_RAILING_HEIGHT,
     railingMode: DEFAULT_STAIR_RAILING_MODE,
-    children: [segment.id],
+    children: [segmentId],
+  })
+}
+
+/**
+ * Creates a stair group with one default stair segment at the given position/rotation.
+ */
+function commitStairPlacement(
+  levelId: LevelNode['id'],
+  position: [number, number, number],
+  rotation: number,
+): void {
+  const { createNodes, nodes } = useScene.getState()
+
+  const stairCount = Object.values(nodes).filter((n) => n.type === 'stair').length
+  const name = `Staircase ${stairCount + 1}`
+  const segment = createDefaultStairSegment()
+
+  const sortedLevels = Object.values(nodes)
+    .filter((node): node is LevelNode => node.type === 'level')
+    .sort((left, right) => left.level - right.level)
+  const currentLevelIndex = sortedLevels.findIndex((level) => level.id === levelId)
+  const nextLevelId = sortedLevels[currentLevelIndex + 1]?.id ?? levelId
+
+  const stair = createDefaultStairNode({
+    name,
+    levelId,
+    nextLevelId,
+    position,
+    rotation,
+    segmentId: segment.id,
   })
 
   createNodes([
@@ -141,6 +173,7 @@ export const StairTool: React.FC = () => {
   const previewRef = useRef<THREE.Group>(null)
   const rotationRef = useRef(0)
   const previousGridPosRef = useRef<[number, number] | null>(null)
+  const lastCanonicalPositionRef = useRef<[number, number, number] | null>(null)
   const currentLevelId = useViewer((state) => state.selection.levelId)
 
   const previewGeometry = useMemo(() => createStairPreviewGeometry(), [])
@@ -151,6 +184,49 @@ export const StairTool: React.FC = () => {
     // Reset rotation when tool activates
     rotationRef.current = 0
     if (previewRef.current) previewRef.current.rotation.y = 0
+    lastCanonicalPositionRef.current = null
+
+    const getPreviewPosition = (
+      position: [number, number, number],
+      rotation: number,
+    ): [number, number, number] => {
+      const segment = createDefaultStairSegment()
+      const stair = createDefaultStairNode({
+        name: 'Staircase Preview',
+        levelId: currentLevelId,
+        nextLevelId: currentLevelId,
+        position,
+        rotation,
+        segmentId: segment.id,
+      })
+      return getFloorStackPreviewPosition({
+        node: stair,
+        position,
+        rotation,
+        levelId: currentLevelId,
+        nodes: {
+          ...useScene.getState().nodes,
+          [stair.id]: stair,
+          [segment.id]: segment,
+        },
+      })
+    }
+
+    const applyPreview = (position: [number, number, number], rotation: number) => {
+      const visualPosition = getPreviewPosition(position, rotation)
+      if (cursorRef.current) {
+        cursorRef.current.position.set(
+          visualPosition[0],
+          visualPosition[1] + GRID_OFFSET,
+          visualPosition[2],
+        )
+      }
+
+      if (previewRef.current) {
+        previewRef.current.position.set(...visualPosition)
+        previewRef.current.rotation.y = rotation
+      }
+    }
 
     // Alignment candidates — anchors of every alignable object; refreshed
     // after each placement. The stair aligns by its ORIGIN point.
@@ -199,15 +275,9 @@ export const StairTool: React.FC = () => {
         event.localPosition[2],
         event.nativeEvent?.altKey === true,
       )
-      const y = event.localPosition[1]
-
-      if (cursorRef.current) {
-        cursorRef.current.position.set(gridX, y + GRID_OFFSET, gridZ)
-      }
-
-      if (previewRef.current) {
-        previewRef.current.position.set(gridX, y, gridZ)
-      }
+      const position: [number, number, number] = [gridX, 0, gridZ]
+      lastCanonicalPositionRef.current = position
+      applyPreview(position, rotationRef.current)
 
       if (
         previousGridPosRef.current &&
@@ -248,7 +318,9 @@ export const StairTool: React.FC = () => {
         event.preventDefault()
         sfxEmitter.emit('sfx:item-rotate')
         rotationRef.current += rotationDelta
-        if (previewRef.current) {
+        if (lastCanonicalPositionRef.current) {
+          applyPreview(lastCanonicalPositionRef.current, rotationRef.current)
+        } else if (previewRef.current) {
           previewRef.current.rotation.y = rotationRef.current
         }
       }

packages/editor/src/components/tools/tool-manager.tsx

@@ -78,6 +78,11 @@ export const ToolManager: React.FC = () => {
   const selectedSlabId = selectedIds.find((id) => nodes[id as AnyNodeId]?.type === 'slab') as
     | SlabNode['id']
     | undefined
+  const selectedSlab = selectedSlabId ? (nodes[selectedSlabId as AnyNodeId] as SlabNode) : null
+  const editingSlabHoleIsManual =
+    selectedSlabId !== undefined &&
+    editingHole?.nodeId === selectedSlabId &&
+    selectedSlab?.holeMetadata?.[editingHole.holeIndex]?.source === 'manual'
 
   // Check if a ceiling is selected
   const selectedCeilingId = selectedIds.find((id) => nodes[id as AnyNodeId]?.type === 'ceiling') as
@@ -92,11 +97,14 @@ export const ToolManager: React.FC = () => {
     phase === 'structure' &&
     mode === 'select' &&
     selectedSlabId !== undefined &&
-    (!editingHole || editingHole.nodeId !== selectedSlabId)
+    !editingSlabHoleIsManual
 
   // Show slab hole editor when editing a hole on the selected slab
   const showSlabHoleEditor =
-    selectedSlabId !== undefined && editingHole !== null && editingHole.nodeId === selectedSlabId
+    selectedSlabId !== undefined &&
+    editingHole !== null &&
+    editingHole.nodeId === selectedSlabId &&
+    editingSlabHoleIsManual
 
   // Show ceiling boundary editor when in structure/select mode with a ceiling selected (but not editing a hole)
   const showCeilingBoundaryEditor =

packages/editor/src/index.tsx

@@ -60,6 +60,7 @@ export {
 } from './components/tools/item/use-placement-coordinator'
 export { CursorSphere } from './components/tools/shared/cursor-sphere'
 export { DragBoundingBox } from './components/tools/shared/drag-bounding-box'
+export { getFloorStackPreviewPosition } from './components/tools/shared/floor-stack-preview'
 // Phase 5 Stage D — PolygonEditor for slab/ceiling boundary + hole editors.
 export {
   PolygonEditor,

packages/editor/src/lib/scene.ts

@@ -355,6 +355,7 @@ function resetEditorInteractionState() {
     selectedReferenceId: null,
     spaces: {},
     editingHole: null,
+    hoveredHole: null,
     isPreviewMode: false,
   })
 }

packages/editor/src/store/use-editor.tsx

@@ -158,6 +158,8 @@ type MaterialPaintSelectionSnapshot = {
   activePaintMaterial: ActivePaintMaterial | null
 }
 
+export type SurfaceHoleTarget = { nodeId: string; holeIndex: number }
+
 export type GuideUiState = {
   locked?: boolean
   scaleReferenceVisible?: boolean
@@ -296,8 +298,10 @@ type EditorState = {
   spaces: Record<string, Space>
   setSpaces: (spaces: Record<string, Space>) => void
   // Generic hole editing (works for slabs, ceilings, and any future polygon nodes)
-  editingHole: { nodeId: string; holeIndex: number } | null
-  setEditingHole: (hole: { nodeId: string; holeIndex: number } | null) => void
+  editingHole: SurfaceHoleTarget | null
+  setEditingHole: (hole: SurfaceHoleTarget | null) => void
+  hoveredHole: SurfaceHoleTarget | null
+  setHoveredHole: (hole: SurfaceHoleTarget | null) => void
   // Preview mode (viewer-like experience inside the editor)
   isPreviewMode: boolean
   setPreviewMode: (preview: boolean) => void
@@ -808,6 +812,14 @@ const useEditor = create<EditorState>()(
       setSpaces: (spaces) => set({ spaces }),
       editingHole: null,
       setEditingHole: (hole) => set({ editingHole: hole }),
+      hoveredHole: null,
+      setHoveredHole: (hole) =>
+        set((state) =>
+          state.hoveredHole?.nodeId === hole?.nodeId &&
+          state.hoveredHole?.holeIndex === hole?.holeIndex
+            ? state
+            : { hoveredHole: hole },
+        ),
       isPreviewMode: false,
       setPreviewMode: (preview) => {
         if (preview) {

packages/nodes/src/column/definition.ts

@@ -19,6 +19,7 @@ const BRACE_HANDLE_OFFSET = 0.3
 const SPREAD_HANDLE_OFFSET = 0.22
 const ROTATE_CORNER_OFFSET = 0.32
 const ROTATE_RING_OFFSET = 0.04
+const MOVE_FRONT_OFFSET = 0.35
 const MIN_COLUMN_HEIGHT = 0.2
 const MIN_COLUMN_WIDTH = 0.1
 const MIN_COLUMN_DEPTH = 0.1
@@ -241,6 +242,29 @@ function columnRotateHandle(): HandleDescriptor<ColumnNodeType> {
   }
 }
 
+function columnMoveHandle(): HandleDescriptor<ColumnNodeType> {
+  return {
+    kind: 'translate',
+    placement: {
+      // Low to the floor at the front edge (matches the item move grip) so it
+      // reads as a floor-move grip and stays clear of the body resize / rotate
+      // handles that sit at mid-height.
+      position: (n) => {
+        const { halfZ } = columnFootprintHalf(n)
+        return [0, 0.02, halfZ + MOVE_FRONT_OFFSET]
+      },
+    },
+    apply: (_n, pos) => ({ position: [pos[0], pos[1], pos[2]] }),
+    snapExtents: (n) => {
+      const { halfX, halfZ } = columnFootprintHalf(n)
+      const dimX = Math.max(halfX * 2, MIN_COLUMN_WIDTH)
+      const dimZ = Math.max(halfZ * 2, MIN_COLUMN_DEPTH)
+      const swap = Math.abs(Math.sin(n.rotation ?? 0)) > 0.9
+      return [swap ? dimZ : dimX, swap ? dimX : dimZ]
+    },
+  }
+}
+
 function columnHandles(node: ColumnNodeType): HandleDescriptor<ColumnNodeType>[] {
   // 1. Height (universal).
   // 2. Footprint arrows depending on supportStyle + crossSection:
@@ -265,7 +289,7 @@ function columnHandles(node: ColumnNodeType): HandleDescriptor<ColumnNodeType>[]
   } else {
     handles.push(columnAxisHandle('x'), columnAxisHandle('z'))
   }
-  handles.push(columnRotateHandle())
+  handles.push(columnRotateHandle(), columnMoveHandle())
   return handles
 }
 

packages/nodes/src/column/move-tool.tsx

@@ -17,6 +17,7 @@ import {
 import {
   CursorSphere,
   DragBoundingBox,
+  getFloorStackPreviewPosition,
   markToolCancelConsumed,
   triggerSFX,
   useEditor,
@@ -74,6 +75,16 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
         ? (node.metadata as Record<string, unknown>)
         : {}
     const isNew = !!meta.isNew
+    const getVisualPosition = (
+      position: [number, number, number],
+      rotation = rotationY,
+    ): [number, number, number] =>
+      getFloorStackPreviewPosition({
+        node,
+        position,
+        rotation,
+        levelId: node.parentId ?? null,
+      })
 
     // Alignment candidates — every other alignable object's anchors, gathered
     // once (the scene graph is stable during the imperative drag).
@@ -81,19 +92,23 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
 
     const applyPreview = (position: [number, number, number]) => {
       lastPosition = position
-      setPreviewPosition(position)
+      const visualPosition = getVisualPosition(position)
+      setPreviewPosition(visualPosition)
       setPreviewRotation(rotationY)
       useLiveTransforms.getState().set(node.id, {
         position,
         rotation: rotationY,
       })
+      useScene.getState().markDirty(node.id as AnyNodeId)
       const m = sceneRegistry.nodes.get(node.id)
       if (m) {
-        m.position.set(position[0], position[1], position[2])
+        m.position.set(...visualPosition)
         m.rotation.y = rotationY
       }
     }
 
+    setPreviewPosition(getVisualPosition(node.position, node.rotation))
+
     const onGridMove = (event: GridEvent) => {
       hasMoved = true
       let x = snapToGridStep(event.localPosition[0])
@@ -145,11 +160,16 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
 
       if (nodeId && useScene.getState().nodes[nodeId]) {
         committed = true
-        useLiveTransforms.getState().clear(nodeId)
         useScene.temporal.getState().resume()
         useScene
           .getState()
           .updateNode(nodeId, { position, rotation: rotationY, ...(isNew ? { metadata: {} } : {}) })
+        useLiveTransforms.getState().clear(nodeId)
+        const m = sceneRegistry.nodes.get(nodeId)
+        if (m) {
+          m.position.set(...getVisualPosition(position, rotationY))
+          m.rotation.y = rotationY
+        }
       } else if (node.parentId) {
         const column = ColumnNodeSchema.parse({
           ...node,
@@ -174,9 +194,10 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
       useAlignmentGuides.getState().clear()
       const m = sceneRegistry.nodes.get(node.id)
       if (m) {
-        m.position.set(node.position[0], node.position[1], node.position[2])
+        m.position.set(...getVisualPosition(node.position, node.rotation))
         m.rotation.y = node.rotation
       }
+      useScene.getState().markDirty(node.id as AnyNodeId)
       useScene.temporal.getState().resume()
       markToolCancelConsumed()
       exitMoveMode()
@@ -197,9 +218,10 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
       if (!committed) {
         const m = sceneRegistry.nodes.get(node.id)
         if (m) {
-          m.position.set(node.position[0], node.position[1], node.position[2])
+          m.position.set(...getVisualPosition(node.position, node.rotation))
           m.rotation.y = node.rotation
         }
+        useScene.getState().markDirty(node.id as AnyNodeId)
         useScene.temporal.getState().resume()
       }
     }

packages/nodes/src/column/tool.tsx

@@ -13,7 +13,7 @@ import {
   useAlignmentGuides,
   useScene,
 } from '@pascal-app/core'
-import { triggerSFX, usePlacementPreview } from '@pascal-app/editor'
+import { getFloorStackPreviewPosition, triggerSFX, usePlacementPreview } from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useMemo, useRef } from 'react'
 import type { Group } from 'three'
@@ -91,13 +91,20 @@ const ColumnTool = () => {
         useAlignmentGuides.getState().clear()
       }
 
-      cursorRef.current?.position.set(ax, event.localPosition[1], az)
+      const position: [number, number, number] = [ax, 0, az]
+      const visualPosition = getFloorStackPreviewPosition({
+        node: previewNode,
+        position,
+        rotation: previewNode.rotation,
+        levelId: activeLevelId,
+      })
+      cursorRef.current?.position.set(...visualPosition)
 
       // Publish a transient, positioned preview node for the 2D floor-plan
       // ghost (the 3D `ColumnPreview` mesh is hidden in 2D). The floor-plan
       // placement-preview layer renders this node's footprint at the snapped,
       // aligned cursor so users see the pillar before they click.
-      usePlacementPreview.getState().set({ ...previewNode, position: [ax, 0, az] })
+      usePlacementPreview.getState().set({ ...previewNode, position })
 
       const prev = previousSnapRef.current
       if (!prev || prev[0] !== ax || prev[1] !== az) {

packages/nodes/src/shared/move-roof-tool.tsx

@@ -5,6 +5,7 @@ import {
   type FenceNode,
   type GridEvent,
   type LevelNode,
+  nodeRegistry,
   type RoofNode,
   type RoofSegmentNode,
   resolveAlignment,
@@ -19,6 +20,7 @@ import {
 import {
   CursorSphere,
   clearRoofDuplicateMetadata,
+  getFloorStackPreviewPosition,
   snapFenceDraftPoint,
   triggerSFX,
   useEditor,
@@ -113,6 +115,11 @@ export const MoveRoofTool: React.FC<{
 
     // Track pending rotation — no store updates during drag
     let pendingRotation: number = movingNode.rotation as number
+    let lastLocalPosition: [number, number, number] = [
+      movingNode.position[0],
+      movingNode.position[1],
+      movingNode.position[2],
+    ]
 
     // For roof-segment moves: the selection was cleared before entering move mode,
     // so isSelected=false on the parent roof, hiding individual segment meshes and
@@ -150,6 +157,20 @@ export const MoveRoofTool: React.FC<{
     }
 
     const levelId = resolveLevelId()
+    const isFloorPlaced = nodeRegistry.get(movingNode.type)?.capabilities?.floorPlaced !== undefined
+    const getPreviewPosition = (
+      position: [number, number, number],
+      rotation = pendingRotation,
+    ): [number, number, number] => {
+      if (!isFloorPlaced) return position
+      return getFloorStackPreviewPosition({
+        node: movingNode,
+        position,
+        rotation,
+        levelId,
+        nodes: useScene.getState().nodes,
+      })
+    }
     const levelNode =
       levelId && useScene.getState().nodes[levelId as AnyNodeId]?.type === 'level'
         ? (useScene.getState().nodes[levelId as AnyNodeId] as LevelNode)
@@ -260,20 +281,28 @@ export const MoveRoofTool: React.FC<{
       }
 
       previousGridPosRef.current = [gridX, gridZ]
-      setCursorWorldPos([lx, event.localPosition[1], lz])
 
       const [localX, localZ] = computeLocal(gridX, gridZ, y, lx, lz)
+      lastLocalPosition = [localX, movingNode.position[1], localZ]
+      const previewPosition = getPreviewPosition(lastLocalPosition)
+      setCursorWorldPos(isFloorPlaced ? previewPosition : [lx, event.localPosition[1], lz])
 
       // Directly update the Three.js mesh — no store update during drag
       const mesh = sceneRegistry.nodes.get(movingNode.id)
       if (mesh) {
+        if (isFloorPlaced) {
+          mesh.position.set(...previewPosition)
+        } else {
           mesh.position.x = localX
           mesh.position.z = localZ
         }
+      }
 
-      // Publish world-space position so the 2D floorplan can track the drag
+      // Publish canonical position so the 2D floorplan can track the drag.
+      // Floor-placed parents (stairs) stay in their committed local frame;
+      // the lifted Y remains presentation-only in the 3D view.
       useLiveTransforms.getState().set(movingNode.id, {
-        position: [gridX, y, gridZ],
+        position: isFloorPlaced ? lastLocalPosition : [gridX, y, gridZ],
         rotation: pendingRotation,
       })
     }
@@ -359,7 +388,14 @@ export const MoveRoofTool: React.FC<{
 
         // Directly update the Three.js mesh — no store update during drag
         const mesh = sceneRegistry.nodes.get(movingNode.id)
-        if (mesh) mesh.rotation.y = pendingRotation
+        if (mesh) {
+          mesh.rotation.y = pendingRotation
+          if (isFloorPlaced) {
+            const previewPosition = getPreviewPosition(lastLocalPosition, pendingRotation)
+            mesh.position.set(...previewPosition)
+            setCursorWorldPos(previewPosition)
+          }
+        }
 
         // Update live transform rotation for 2D floorplan
         const currentLive = useLiveTransforms.getState().get(movingNode.id)

packages/nodes/src/shelf/definition.ts

@@ -1,4 +1,5 @@
 import type { HandleDescriptor, NodeDefinition, ShelfNode as ShelfNodeType } from '@pascal-app/core'
+import { sanitizeShelfDimensions } from './dimensions'
 import { buildShelfFloorplan } from './floorplan'
 import { shelfResizeAffordance, shelfRotateAffordance } from './floorplan-affordances'
 import { shelfFloorplanMoveTarget } from './floorplan-move'
@@ -10,6 +11,7 @@ const SIDE_HANDLE_OFFSET = 0.18
 const HEIGHT_HANDLE_OFFSET = 0.22
 const ROTATE_CORNER_OFFSET = 0.32
 const ROTATE_RING_OFFSET = 0.04
+const MOVE_FRONT_OFFSET = 0.35
 const MIN_SHELF_WIDTH = 0.3
 const MIN_SHELF_DEPTH = 0.1
 const MIN_SHELF_HEIGHT = 0.05
@@ -95,8 +97,35 @@ function shelfRotateHandle(): HandleDescriptor<ShelfNodeType> {
   }
 }
 
+function shelfMoveHandle(): HandleDescriptor<ShelfNodeType> {
+  return {
+    kind: 'translate',
+    placement: {
+      // Low to the floor at the front edge (matches the item move grip) so it
+      // reads as a floor-move grip and stays clear of the body resize / rotate
+      // handles that sit at mid-height.
+      position: (n) => {
+        const shelf = sanitizeShelfDimensions(n as ShelfNode)
+        return [0, 0.02, shelf.depth / 2 + MOVE_FRONT_OFFSET]
+      },
+    },
+    apply: (_n, pos) => ({ position: [pos[0], pos[1], pos[2]] }),
+    snapExtents: (n) => {
+      const shelf = sanitizeShelfDimensions(n as ShelfNode)
+      const swap = Math.abs(Math.sin(shelf.rotation[1] ?? 0)) > 0.9
+      return [swap ? shelf.depth : shelf.width, swap ? shelf.width : shelf.depth]
+    },
+  }
+}
+
 function shelfHandles(_node: ShelfNodeType): HandleDescriptor<ShelfNodeType>[] {
-  return [shelfWidthHandle(), shelfDepthHandle(), shelfHeightHandle(), shelfRotateHandle()]
+  return [
+    shelfWidthHandle(),
+    shelfDepthHandle(),
+    shelfHeightHandle(),
+    shelfRotateHandle(),
+    shelfMoveHandle(),
+  ]
 }
 
 export const shelfDefinition: NodeDefinition<typeof ShelfNode> = {
@@ -158,7 +187,7 @@ export const shelfDefinition: NodeDefinition<typeof ShelfNode> = {
     // shelf sitting over a raised slab visually rests on top of it.
     floorPlaced: {
       footprint: (node) => {
-        const shelf = node as ShelfNode
+        const shelf = sanitizeShelfDimensions(node as ShelfNode)
         return {
           dimensions: [shelf.width, shelf.height, shelf.depth] as [number, number, number],
           rotation: shelf.rotation,
@@ -189,7 +218,7 @@ export const shelfDefinition: NodeDefinition<typeof ShelfNode> = {
   // `children`. Lets <GeometrySystem> skip the dispose+rebuild (and the
   // pointer enter/leave churn it causes) when an item reparents onto a row.
   geometryKey: (n) => {
-    const s = n as ShelfNodeType
+    const s = sanitizeShelfDimensions(n as ShelfNode)
     return JSON.stringify([
       s.style,
       s.width,

packages/nodes/src/shelf/dimensions.ts

@@ -0,0 +1,18 @@
+import type { ShelfNode } from './schema'
+
+function clampShelfDim(value: unknown, lo: number, hi: number, fallback: number): number {
+  const v = typeof value === 'number' && Number.isFinite(value) ? value : fallback
+  return Math.min(Math.max(v, lo), hi)
+}
+
+export function sanitizeShelfDimensions(node: ShelfNode): ShelfNode {
+  return {
+    ...node,
+    width: clampShelfDim(node.width, 0.3, 3.0, 1.2),
+    depth: clampShelfDim(node.depth, 0.1, 1.0, 0.3),
+    thickness: clampShelfDim(node.thickness, 0.01, 0.1, 0.04),
+    height: clampShelfDim(node.height, 0.05, 2.5, 0.9),
+    rows: Math.round(clampShelfDim(node.rows, 1, 8, 1)),
+    columns: Math.round(clampShelfDim(node.columns, 1, 6, 1)),
+  }
+}

packages/nodes/src/shelf/floorplan-move.ts

@@ -10,6 +10,7 @@ import {
 } from '@pascal-app/core'
 import {
   applyFloorplanAlignment,
+  getFloorStackPreviewPosition,
   snapPointToGrid,
   triggerSFX,
   type WallPlanPoint,
@@ -82,6 +83,12 @@ export const shelfFloorplanMoveTarget: FloorplanMoveTarget<ShelfNode> = ({ node,
         triggerSFX('sfx:grid-snap')
         lastSnapKey = snapKey
       }
+      const visualPosition = getFloorStackPreviewPosition({
+        node,
+        position: next,
+        rotation: node.rotation,
+        levelId: node.parentId ?? null,
+      })
       // Single source of truth — write the absolute position straight to
       // the scene (history is paused by the overlay). Both the 2D SVG and
       // the 3D group transform read `node.position` reactively, so they
@@ -90,7 +97,7 @@ export const shelfFloorplanMoveTarget: FloorplanMoveTarget<ShelfNode> = ({ node,
       useScene.getState().updateNodes([
         {
           id: shelfId,
-          data: { position: next },
+          data: { position: visualPosition },
         },
       ])
     },

packages/nodes/src/shelf/floorplan.ts

@@ -1,4 +1,5 @@
 import type { FloorplanGeometry, GeometryContext } from '@pascal-app/core'
+import { sanitizeShelfDimensions } from './dimensions'
 import type { ShelfResizePayload } from './floorplan-affordances'
 import type { ShelfNode } from './schema'
 
@@ -25,15 +26,16 @@ const ROTATE_ARROW_CORNER_OFFSET = 0.22
  * (engaged from the action-menu Move button, not from these arrows).
  */
 export function buildShelfFloorplan(node: ShelfNode, ctx?: GeometryContext): FloorplanGeometry {
-  const [px, , pz] = node.position
-  const ry = node.rotation[1] ?? 0
+  const shelf = sanitizeShelfDimensions(node)
+  const [px, , pz] = shelf.position
+  const ry = shelf.rotation[1] ?? 0
   // Floor-plan plots at `-ry` so SVG's CW-with-y-down `rotate` direction
   // ends up visually matching Three.js Y-rotation (CCW from a top-down
   // view) — same `rotation` value rotates the same way in both views.
   // Stair already does this; column / shelf / roof-segment now do too.
   const planRy = -ry
-  const halfW = node.width / 2
-  const halfD = node.depth / 2
+  const halfW = shelf.width / 2
+  const halfD = shelf.depth / 2
   const isSelected = ctx?.viewState?.selected ?? false
 
   // Floor-plan fill: a single neutral fill regardless of `material`.
@@ -44,8 +46,8 @@ export function buildShelfFloorplan(node: ShelfNode, ctx?: GeometryContext): Flo
       kind: 'rect',
       x: -halfW,
       y: -halfD,
-      width: node.width,
-      height: node.depth,
+      width: shelf.width,
+      height: shelf.depth,
       fill: '#d6d3d1',
       stroke: '#1f2937',
       strokeWidth: 0.015,
@@ -55,17 +57,17 @@ export function buildShelfFloorplan(node: ShelfNode, ctx?: GeometryContext): Flo
 
   // Show column dividers for grid-style shelves so the cubby / bookshelf
   // grid is visible from above.
-  if ((node.style === 'bookshelf' || node.style === 'cubby') && node.columns > 1) {
-    const innerWidth = node.width - 2 * node.thickness
-    const colStep = innerWidth / node.columns
-    for (let c = 1; c < node.columns; c++) {
+  if ((shelf.style === 'bookshelf' || shelf.style === 'cubby') && shelf.columns > 1) {
+    const innerWidth = shelf.width - 2 * shelf.thickness
+    const colStep = innerWidth / shelf.columns
+    for (let c = 1; c < shelf.columns; c++) {
       const x = -innerWidth / 2 + c * colStep
       footprintChildren.push({
         kind: 'line',
         x1: x,
-        y1: -halfD + node.thickness,
+        y1: -halfD + shelf.thickness,
         x2: x,
-        y2: halfD - node.thickness,
+        y2: halfD - shelf.thickness,
         stroke: '#1f2937',
         strokeWidth: 0.012,
         opacity: 0.7,

packages/nodes/src/shelf/geometry.ts

@@ -7,6 +7,7 @@ import {
   type RenderShading,
 } from '@pascal-app/viewer'
 import { BoxGeometry, FrontSide, Group, type Material, Mesh } from 'three'
+import { sanitizeShelfDimensions } from './dimensions'
 import type { ShelfNode } from './schema'
 
 /**
@@ -69,10 +70,11 @@ function getShelfMaterial(node: ShelfNode, shading: RenderShading): Material {
 }
 
 export function buildShelfGeometry(
-  node: ShelfNode,
+  rawNode: ShelfNode,
   _ctx?: unknown,
   shading: RenderShading = 'rendered',
 ): Group {
+  const node = sanitizeShelfDimensions(rawNode)
   const group = new Group()
   group.name = 'shelf-geometry'
 
@@ -343,8 +345,9 @@ function addCornerPosts(
  * can host in the lowest cell.
  */
 export function shelfRowSurfaceYs(node: ShelfNode): number[] {
-  const ys = boardCenterYs(node).map((y) => y + node.thickness / 2)
-  const bottomApplies = node.style === 'cubby' || node.style === 'bookshelf'
-  if (node.withBottom && bottomApplies) ys.unshift(node.thickness)
+  const safe = sanitizeShelfDimensions(node)
+  const ys = boardCenterYs(safe).map((y) => y + safe.thickness / 2)
+  const bottomApplies = safe.style === 'cubby' || safe.style === 'bookshelf'
+  if (safe.withBottom && bottomApplies) ys.unshift(safe.thickness)
   return ys
 }

packages/nodes/src/shelf/tool.tsx

@@ -15,7 +15,7 @@ import {
   useAlignmentGuides,
   useScene,
 } from '@pascal-app/core'
-import { triggerSFX } from '@pascal-app/editor'
+import { getFloorStackPreviewPosition, triggerSFX } from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useMemo, useRef } from 'react'
 import { type Group, Vector3 } from 'three'
@@ -70,16 +70,16 @@ function getLevelLocalPosition(
     const local = (event as GridEvent).localPosition
     if (local) {
       const [sx, sz] = snapPointToGrid([local[0], local[2]], GRID_STEP)
-      return [sx, local[1] ?? 0, sz]
+      return [sx, 0, sz]
     }
     const [sx, sz] = snapPointToGrid([event.position[0], event.position[2]], GRID_STEP)
-    return [sx, event.position[1], sz]
+    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], GRID_STEP)
-  return [sx, worldVector.y, sz]
+  return [sx, 0, sz]
 }
 
 const ShelfTool = () => {
@@ -150,8 +150,15 @@ const ShelfTool = () => {
         useAlignmentGuides.getState().clear()
       }
 
-      cursorRef.current?.position.set(ax, event.localPosition[1], az)
-      lastCursorRef.current = [ax, event.localPosition[1], az]
+      const position: [number, number, number] = [ax, 0, az]
+      const visualPosition = getFloorStackPreviewPosition({
+        node: previewNode,
+        position,
+        rotation: previewNode.rotation,
+        levelId: activeLevelId,
+      })
+      cursorRef.current?.position.set(...visualPosition)
+      lastCursorRef.current = position
 
       const prev = previousSnapRef.current
       if (!prev || prev[0] !== ax || prev[1] !== az) {

packages/nodes/src/slab/hole-editor.tsx

@@ -24,6 +24,7 @@ export const SlabHoleEditor: React.FC<{ slabId: SlabNode['id']; holeIndex: numbe
   const slab = slabNode?.type === 'slab' ? (slabNode as SlabNode) : null
   const holes = slab?.holes || []
   const hole = holes[holeIndex]
+  const metadata = slab?.holeMetadata?.[holeIndex]
 
   const handlePolygonChange = useCallback(
     (newPolygon: Array<[number, number]>) => {
@@ -60,7 +61,7 @@ export const SlabHoleEditor: React.FC<{ slabId: SlabNode['id']; holeIndex: numbe
     }
   }, [slabId])
 
-  if (!(slab && hole) || hole.length < 3) return null
+  if (!(slab && hole) || hole.length < 3 || metadata?.source !== 'manual') return null
 
   return (
     <PolygonEditor

packages/nodes/src/spawn/definition.ts

@@ -1,8 +1,23 @@
-import type { NodeDefinition } from '@pascal-app/core'
+import type { HandleDescriptor, NodeDefinition, SpawnNode as SpawnNodeType } from '@pascal-app/core'
 import { buildSpawnFloorplan } from './floorplan'
 import { spawnParametrics } from './parametrics'
 import { SpawnNode } from './schema'
 
+const SPAWN_FOOTPRINT = 0.6
+const MOVE_FRONT_OFFSET = 0.35
+
+function spawnMoveHandle(): HandleDescriptor<SpawnNodeType> {
+  return {
+    kind: 'translate',
+    placement: {
+      // Low to the floor at the front edge (matches the item move grip).
+      position: () => [0, 0.02, SPAWN_FOOTPRINT / 2 + MOVE_FRONT_OFFSET],
+    },
+    apply: (_n, pos) => ({ position: [pos[0], pos[1], pos[2]] }),
+    snapExtents: () => [SPAWN_FOOTPRINT, SPAWN_FOOTPRINT],
+  }
+}
+
 export const spawnDefinition: NodeDefinition<typeof SpawnNode> = {
   kind: 'spawn',
   schemaVersion: 1,
@@ -37,6 +52,7 @@ export const spawnDefinition: NodeDefinition<typeof SpawnNode> = {
   },
 
   parametrics: spawnParametrics,
+  handles: [spawnMoveHandle()],
 
   renderer: {
     kind: 'parametric',

packages/nodes/src/spawn/renderer.tsx

@@ -1,6 +1,12 @@
 'use client'
 
-import { type SpawnNode, useLiveTransforms, useRegistry } from '@pascal-app/core'
+import {
+  type AnyNodeId,
+  type SpawnNode,
+  useLiveNodeOverrides,
+  useLiveTransforms,
+  useRegistry,
+} from '@pascal-app/core'
 import { createDefaultMaterial, useNodeEvents, useViewer } from '@pascal-app/viewer'
 import { useMemo, useRef } from 'react'
 import { Color, type Group, Shape } from 'three'
@@ -20,6 +26,11 @@ const SPAWN_COLOR = new Color('#22c55e')
 const SpawnRenderer = ({ node }: { node: SpawnNode }) => {
   const ref = useRef<Group>(null!)
   const handlers = useNodeEvents(node, 'spawn')
+  const liveOverride = useLiveNodeOverrides((state) => state.get(node.id as AnyNodeId))
+  const effectiveNode = useMemo(
+    () => (liveOverride ? ({ ...node, ...liveOverride } as SpawnNode) : node),
+    [node, liveOverride],
+  )
   const liveTransform = useLiveTransforms((state) => state.get(node.id))
   const walkthroughMode = useViewer((state) => state.walkthroughMode)
   const shading = useViewer((state) => state.shading)
@@ -52,10 +63,10 @@ const SpawnRenderer = ({ node }: { node: SpawnNode }) => {
 
   return (
     <group
-      position={liveTransform?.position ?? node.position}
+      position={liveTransform?.position ?? effectiveNode.position}
       ref={ref}
-      rotation={[0, liveTransform?.rotation ?? node.rotation, 0]}
-      visible={!walkthroughMode}
+      rotation={[0, liveTransform?.rotation ?? effectiveNode.rotation, 0]}
+      visible={!walkthroughMode && effectiveNode.visible !== false}
     >
       <mesh position={[0, 0.09, 0]} rotation={[-Math.PI / 2, 0, 0]} {...handlers}>
         <ringGeometry args={[0.34, 0.48, 48]} />

packages/nodes/src/spawn/tool.tsx

@@ -1,7 +1,12 @@
 'use client'
 
 import { emitter, type GridEvent, SpawnNode, sceneRegistry, useScene } from '@pascal-app/core'
-import { CursorSphere, triggerSFX, useEditor } from '@pascal-app/editor'
+import {
+  CursorSphere,
+  getFloorStackPreviewPosition,
+  triggerSFX,
+  useEditor,
+} from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useRef } from 'react'
 import { type Group, Vector3 } from 'three'
@@ -20,16 +25,12 @@ function getExistingSpawnIds() {
 function getLevelLocalPosition(levelId: string, event: GridEvent): [number, number, number] {
   const levelObject = sceneRegistry.nodes.get(levelId)
   if (!levelObject) {
-    return [
-      roundToHalf(event.localPosition[0]),
-      event.localPosition[1],
-      roundToHalf(event.localPosition[2]),
-    ]
+    return [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), worldVector.y, roundToHalf(worldVector.z)]
+  return [roundToHalf(worldVector.x), 0, roundToHalf(worldVector.z)]
 }
 
 /**
@@ -53,7 +54,19 @@ const SpawnTool = () => {
       // same half-meter snap the legacy tool uses.
       const nextX = roundToHalf(event.localPosition[0])
       const nextZ = roundToHalf(event.localPosition[2])
-      cursorRef.current?.position.set(nextX, event.localPosition[1], nextZ)
+      const position: [number, number, number] = [nextX, 0, nextZ]
+      const previewNode = SpawnNode.parse({
+        name: 'Spawn Point',
+        position,
+        rotation: 0,
+      })
+      const visualPosition = getFloorStackPreviewPosition({
+        node: previewNode,
+        position,
+        rotation: 0,
+        levelId: activeLevelId,
+      })
+      cursorRef.current?.position.set(...visualPosition)
 
       // Fire grid-snap SFX only when the snapped position crosses a cell,
       // not every frame the mouse moves within the same cell. Matches the

packages/nodes/src/stair/definition.ts

@@ -1,8 +1,10 @@
 import {
   type HandleDescriptor,
   type NodeDefinition,
+  type SceneApi,
   StairNode as StairNodeSchema,
   type StairNode as StairNodeType,
+  type StairSegmentNode,
   stairFootprintAABB,
 } from '@pascal-app/core'
 
@@ -27,6 +29,7 @@ const CURVED_INNER_RING_MIN = 0.05
 // the footprint. Same pattern as elevator / column / shelf / roof-segment.
 const STAIR_ROTATE_CORNER_OFFSET = 0.4
 const STAIR_ROTATE_RING_OFFSET = 0.08
+const STAIR_MOVE_FRONT_OFFSET = 0.35
 
 type CurvedStairGeom = {
   isSpiral: boolean
@@ -42,6 +45,14 @@ type CurvedStairGeom = {
   minInnerRadius: number
 }
 
+type StairMoveBounds = {
+  minX: number
+  maxX: number
+  minZ: number
+  maxZ: number
+  height: number
+}
+
 function readCurvedStairGeometry(node: StairNodeType): CurvedStairGeom {
   const isSpiral = node.stairType === 'spiral'
   const stepCount = Math.max(2, Math.round(node.stepCount ?? 10))
@@ -71,6 +82,79 @@ function isCurvedOrSpiral(node: StairNodeType): boolean {
   return node.stairType === 'curved' || node.stairType === 'spiral'
 }
 
+function rotateLocalXZ(x: number, z: number, angle: number): [number, number] {
+  const cos = Math.cos(angle)
+  const sin = Math.sin(angle)
+  return [x * cos + z * sin, -x * sin + z * cos]
+}
+
+function fallbackStraightStairMoveBounds(node: StairNodeType): StairMoveBounds {
+  const width = Math.max(node.width ?? 1, MIN_CURVED_WIDTH)
+  const depth = Math.max(width, 1)
+  return {
+    minX: -width / 2,
+    maxX: width / 2,
+    minZ: 0,
+    maxZ: depth,
+    height: Math.max(node.totalRise ?? 2.5, 0.1),
+  }
+}
+
+function readStraightStairMoveBounds(node: StairNodeType, sceneApi: SceneApi): StairMoveBounds {
+  const segments = (node.children ?? [])
+    .map((childId) => sceneApi.get<StairSegmentNode>(childId as never))
+    .filter((child): child is StairSegmentNode => child?.type === 'stair-segment')
+
+  if (segments.length === 0) return fallbackStraightStairMoveBounds(node)
+
+  const transforms = computeStairSegmentFloorStackTransforms(segments)
+  let minX = Number.POSITIVE_INFINITY
+  let maxX = Number.NEGATIVE_INFINITY
+  let minZ = Number.POSITIVE_INFINITY
+  let maxZ = Number.NEGATIVE_INFINITY
+  let height = 0
+
+  segments.forEach((segment, index) => {
+    const transform = transforms[index]
+    if (!transform) return
+    const halfWidth = segment.width / 2
+    const corners = [
+      [-halfWidth, 0],
+      [halfWidth, 0],
+      [-halfWidth, segment.length],
+      [halfWidth, segment.length],
+    ] as const
+    for (const [x, z] of corners) {
+      const [rx, rz] = rotateLocalXZ(x, z, transform.rotation)
+      minX = Math.min(minX, transform.position[0] + rx)
+      maxX = Math.max(maxX, transform.position[0] + rx)
+      minZ = Math.min(minZ, transform.position[2] + rz)
+      maxZ = Math.max(maxZ, transform.position[2] + rz)
+    }
+    height = Math.max(
+      height,
+      transform.position[1] + Math.max(segment.height, segment.thickness, 0.01),
+    )
+  })
+
+  if (![minX, maxX, minZ, maxZ].every(Number.isFinite)) {
+    return fallbackStraightStairMoveBounds(node)
+  }
+  return { minX, maxX, minZ, maxZ, height: Math.max(height, 0.1) }
+}
+
+function readStairMoveBounds(node: StairNodeType, sceneApi: SceneApi): StairMoveBounds {
+  if (!isCurvedOrSpiral(node)) return readStraightStairMoveBounds(node, sceneApi)
+  const g = readCurvedStairGeometry(node)
+  return {
+    minX: -g.outerRadius,
+    maxX: g.outerRadius,
+    minZ: -g.outerRadius,
+    maxZ: g.outerRadius,
+    height: g.totalRise,
+  }
+}
+
 function curvedRiseHandle(): HandleDescriptor<StairNodeType> {
   return {
     kind: 'linear-resize',
@@ -266,6 +350,29 @@ function stairRotateHandle(): HandleDescriptor<StairNodeType> {
   }
 }
 
+function stairMoveHandle(): HandleDescriptor<StairNodeType> {
+  return {
+    kind: 'translate',
+    placement: {
+      // Low to the floor at the front edge (matches the item move grip) so it
+      // reads as a floor-move grip and stays clear of the body resize / rotate
+      // handles that sit at mid-height.
+      position: (n, sceneApi) => {
+        const bounds = readStairMoveBounds(n, sceneApi)
+        return [(bounds.minX + bounds.maxX) / 2, 0.02, bounds.maxZ + STAIR_MOVE_FRONT_OFFSET]
+      },
+    },
+    apply: (_n, pos) => ({ position: [pos[0], pos[1], pos[2]] }),
+    snapExtents: (n, sceneApi) => {
+      const bounds = readStairMoveBounds(n, sceneApi)
+      const dimX = Math.max(bounds.maxX - bounds.minX, MIN_CURVED_WIDTH)
+      const dimZ = Math.max(bounds.maxZ - bounds.minZ, MIN_CURVED_WIDTH)
+      const swap = Math.abs(Math.sin(n.rotation ?? 0)) > 0.9
+      return [swap ? dimZ : dimX, swap ? dimX : dimZ]
+    },
+  }
+}
+
 function stairHandles(node: StairNodeType): HandleDescriptor<StairNodeType>[] {
   // Straight stairs have no parent-level shape arrows — the segment
   // children each render their own (width / length / height). Curved +
@@ -282,10 +389,14 @@ function stairHandles(node: StairNodeType): HandleDescriptor<StairNodeType>[] {
       curvedSweepHandle('end'),
     )
   }
-  handles.push(stairRotateHandle())
+  handles.push(stairRotateHandle(), stairMoveHandle())
   return handles
 }
 
+import {
+  computeStairSegmentFloorStackTransforms,
+  getStairFloorPlacedFootprints,
+} from './floor-stack'
 import { buildStairFloorplan } from './floorplan'
 import {
   curvedStairInnerRadiusAffordance,
@@ -330,6 +441,10 @@ export const stairDefinition: NodeDefinition<typeof StairNode> = {
     },
     duplicable: true,
     deletable: true,
+    floorPlaced: {
+      footprints: (node, ctx) =>
+        ctx ? getStairFloorPlacedFootprints(node as StairNodeType, ctx.nodes) : [],
+    },
   },
 
   // Bespoke move shared with roof / roof-segment / stair-segment via

packages/nodes/src/stair/floor-stack.test.ts

@@ -0,0 +1,177 @@
+import { beforeEach, describe, expect, test } from 'bun:test'
+import {
+  type AnyNode,
+  type AnyNodeDefinition,
+  getFloorPlacedElevation,
+  nodeRegistry,
+  registerNode,
+  type SlabNode,
+  StairNode,
+  StairSegmentNode,
+  spatialGridManager,
+} from '@pascal-app/core'
+import { stairDefinition } from './definition'
+import { getStairSegmentFloorPlacedFootprints } from './floor-stack'
+
+const LEVEL_ID = 'level_test'
+
+function makeLevel(): AnyNode {
+  return {
+    id: LEVEL_ID,
+    type: 'level',
+    object: 'node',
+    parentId: null,
+    visible: true,
+    metadata: {},
+    children: [],
+    level: 0,
+  } as AnyNode
+}
+
+function addSlab(polygon: Array<[number, number]>, elevation: number, id = `slab_${elevation}`) {
+  const slab = {
+    id,
+    type: 'slab',
+    object: 'node',
+    parentId: LEVEL_ID,
+    visible: true,
+    metadata: {},
+    children: [],
+    polygon,
+    holes: [],
+    holeMetadata: [],
+    elevation,
+    autoFromWalls: false,
+  } as SlabNode
+  spatialGridManager.handleNodeCreated(slab as AnyNode, LEVEL_ID)
+}
+
+describe('stair floor-stack footprints', () => {
+  beforeEach(() => {
+    nodeRegistry._reset()
+    spatialGridManager.clear()
+  })
+
+  test('derives a rotated segment footprint from stair position and rotation', () => {
+    const segment = StairSegmentNode.parse({
+      id: 'sseg_single',
+      width: 2,
+      length: 4,
+      height: 1,
+      thickness: 0.25,
+    })
+    const stair = StairNode.parse({
+      id: 'stair_single',
+      parentId: LEVEL_ID,
+      position: [10, 0, 20],
+      rotation: Math.PI / 2,
+      children: [segment.id],
+    })
+
+    const [footprint] = getStairSegmentFloorPlacedFootprints(stair, [segment])
+
+    expect(footprint?.position?.[0]).toBeCloseTo(12)
+    expect(footprint?.position?.[1]).toBeCloseTo(0)
+    expect(footprint?.position?.[2]).toBeCloseTo(20)
+    expect(footprint?.dimensions).toEqual([2, 1, 4])
+    expect(footprint?.rotation[1]).toBeCloseTo(Math.PI / 2)
+  })
+
+  test('emits one footprint per chained stair segment', () => {
+    const first = StairSegmentNode.parse({
+      id: 'sseg_first',
+      width: 2,
+      length: 4,
+      height: 1,
+      thickness: 0.25,
+    })
+    const second = StairSegmentNode.parse({
+      id: 'sseg_second',
+      attachmentSide: 'left',
+      width: 1.5,
+      length: 3,
+      height: 0.8,
+      thickness: 0.2,
+    })
+    const stair = StairNode.parse({
+      id: 'stair_multi',
+      parentId: LEVEL_ID,
+      position: [0, 0, 0],
+      rotation: 0,
+      children: [first.id, second.id],
+    })
+
+    const footprints = getStairSegmentFloorPlacedFootprints(stair, [first, second])
+
+    expect(footprints).toHaveLength(2)
+    expect(footprints[0]?.position).toEqual([0, 0, 2])
+    expect(footprints[0]?.rotation[1]).toBeCloseTo(0)
+    expect(footprints[1]?.position?.[0]).toBeCloseTo(2.5)
+    expect(footprints[1]?.position?.[1]).toBeCloseTo(1)
+    expect(footprints[1]?.position?.[2]).toBeCloseTo(2)
+    expect(footprints[1]?.rotation[1]).toBeCloseTo(Math.PI / 2)
+  })
+
+  test('uses the max slab elevation across stair segment footprints', () => {
+    registerNode(stairDefinition as unknown as AnyNodeDefinition)
+
+    addSlab(
+      [
+        [-0.6, 1.4],
+        [0.6, 1.4],
+        [0.6, 2.6],
+        [-0.6, 2.6],
+      ],
+      0.25,
+      'slab_low',
+    )
+    addSlab(
+      [
+        [2.2, 1.7],
+        [2.8, 1.7],
+        [2.8, 2.3],
+        [2.2, 2.3],
+      ],
+      0.75,
+      'slab_high',
+    )
+
+    const level = makeLevel()
+    const first = StairSegmentNode.parse({
+      id: 'sseg_resolver_first',
+      width: 2,
+      length: 4,
+      height: 1,
+    })
+    const second = StairSegmentNode.parse({
+      id: 'sseg_resolver_second',
+      attachmentSide: 'left',
+      width: 1.5,
+      length: 3,
+      height: 0.8,
+    })
+    const stair = StairNode.parse({
+      id: 'stair_resolver',
+      parentId: LEVEL_ID,
+      position: [0, 0, 0],
+      rotation: 0,
+      children: [first.id, second.id],
+    })
+    const nodes = {
+      [level.id]: level,
+      [stair.id]: stair,
+      [first.id]: first,
+      [second.id]: second,
+    }
+
+    expect(
+      getFloorPlacedElevation({
+        node: stair,
+        nodes,
+        position: stair.position,
+        rotation: stair.rotation,
+        levelId: LEVEL_ID,
+      }),
+    ).toBeCloseTo(0.75)
+  })
+})

packages/nodes/src/stair/floor-stack.ts

@@ -0,0 +1,114 @@
+import type {
+  AnyNode,
+  AnyNodeId,
+  FloorPlacedFootprint,
+  StairNode,
+  StairSegmentNode,
+} from '@pascal-app/core'
+
+type SegmentTransform = {
+  position: [number, number, number]
+  rotation: number
+}
+
+export function getStairFloorPlacedFootprints(
+  stair: StairNode,
+  nodes: Readonly<Record<AnyNodeId, AnyNode>>,
+): FloorPlacedFootprint[] {
+  const segments = (stair.children ?? [])
+    .map((childId) => nodes[childId as AnyNodeId])
+    .filter((node): node is StairSegmentNode => node?.type === 'stair-segment')
+
+  return getStairSegmentFloorPlacedFootprints(stair, segments)
+}
+
+export function getStairSegmentFloorPlacedFootprints(
+  stair: StairNode,
+  segments: readonly StairSegmentNode[],
+): FloorPlacedFootprint[] {
+  const transforms = computeStairSegmentFloorStackTransforms(segments)
+
+  return segments.map((segment, index) => {
+    const transform = transforms[index]!
+    const [centerOffsetX, centerOffsetZ] = rotateXZ(0, segment.length / 2, transform.rotation)
+    const centerInGroupX = transform.position[0] + centerOffsetX
+    const centerInGroupZ = transform.position[2] + centerOffsetZ
+    const [centerOffsetWorldX, centerOffsetWorldZ] = rotateXZ(
+      centerInGroupX,
+      centerInGroupZ,
+      stair.rotation,
+    )
+
+    return {
+      position: [
+        stair.position[0] + centerOffsetWorldX,
+        stair.position[1] + transform.position[1],
+        stair.position[2] + centerOffsetWorldZ,
+      ],
+      dimensions: [
+        segment.width,
+        Math.max(segment.height, segment.thickness, 0.01),
+        segment.length,
+      ],
+      rotation: [0, stair.rotation + transform.rotation, 0],
+    }
+  })
+}
+
+export function computeStairSegmentFloorStackTransforms(
+  segments: readonly StairSegmentNode[],
+): SegmentTransform[] {
+  const transforms: SegmentTransform[] = []
+  let currentX = 0
+  let currentY = 0
+  let currentZ = 0
+  let currentRot = 0
+
+  for (let index = 0; index < segments.length; index += 1) {
+    const segment = segments[index]!
+
+    if (index > 0) {
+      const previous = segments[index - 1]!
+      let attachX = 0
+      let attachZ = 0
+      let rotationDelta = 0
+
+      switch (segment.attachmentSide) {
+        case 'front':
+          attachX = 0
+          attachZ = previous.length
+          rotationDelta = 0
+          break
+        case 'left':
+          attachX = previous.width / 2
+          attachZ = previous.length / 2
+          rotationDelta = Math.PI / 2
+          break
+        case 'right':
+          attachX = -previous.width / 2
+          attachZ = previous.length / 2
+          rotationDelta = -Math.PI / 2
+          break
+      }
+
+      const [rotatedX, rotatedZ] = rotateXZ(attachX, attachZ, currentRot)
+      currentX += rotatedX
+      currentY += previous.height
+      currentZ += rotatedZ
+      currentRot += rotationDelta
+    }
+
+    transforms.push({
+      position: [currentX, currentY, currentZ],
+      rotation: currentRot,
+    })
+  }
+
+  return transforms
+}
+
+function rotateXZ(x: number, z: number, angle: number): [number, number] {
+  const cos = Math.cos(angle)
+  const sin = Math.sin(angle)
+  return [x * cos + z * sin, -x * sin + z * cos]
+}

packages/viewer/src/components/viewer/lights.tsx

@@ -103,15 +103,26 @@ export function Lights() {
           if (SHADOW_EXCLUDED_TYPES.some((t) => sceneRegistry.byType[t]!.has(id))) continue
           box.expandByObject(obj)
         }
-        if (box.isEmpty()) {
-          // Empty scene: fall back to the origin with a default radius so the
-          // ground still receives a sensible shadow region.
+        box.getBoundingSphere(boundsSphere.current)
+        const center = boundsSphere.current.center
+        const radius = boundsSphere.current.radius
+        // Empty scene OR a node with a NaN position/geometry poisoning the union
+        // box: fall back to the origin with a default radius. The directional
+        // light's position is derived from `focus`, so a single non-finite mesh
+        // must NOT be allowed to make `focus`/`radius` NaN — that breaks every
+        // shadow-casting light's position and renders the whole scene black.
+        const finiteBounds =
+          !box.isEmpty() &&
+          Number.isFinite(center.x) &&
+          Number.isFinite(center.y) &&
+          Number.isFinite(center.z) &&
+          Number.isFinite(radius)
+        if (finiteBounds) {
+          shadowFocus.current.copy(center)
+          shadowRadius.current = radius
+        } else {
           shadowFocus.current.set(0, 0, 0)
           shadowRadius.current = SHADOW_FALLBACK_RADIUS
-        } else {
-          box.getBoundingSphere(boundsSphere.current)
-          shadowFocus.current.copy(boundsSphere.current.center)
-          shadowRadius.current = boundsSphere.current.radius
         }
       }
 

packages/viewer/src/systems/floor-elevation/floor-elevation-system.tsx

@@ -1,15 +1,43 @@
 import {
   type AnyNode,
   type AnyNodeId,
+  getEffectiveNode,
+  getFloorStackedPosition,
   nodeRegistry,
-  resolveLevelId,
   sceneRegistry,
-  spatialGridManager,
+  useLiveTransforms,
   useScene,
 } from '@pascal-app/core'
 import { useFrame } from '@react-three/fiber'
 import type * as THREE from 'three'
 
+type PositionedNode = AnyNode & {
+  position?: [number, number, number]
+  rotation?: [number, number, number] | number
+}
+
+function withLiveTransform(node: AnyNode, id: string): AnyNode {
+  const liveTransform = useLiveTransforms.getState().get(id)
+  if (!liveTransform) return node
+
+  const currentRotation = (node as PositionedNode).rotation
+  const rotation = Array.isArray(currentRotation)
+    ? ([currentRotation[0] ?? 0, liveTransform.rotation, currentRotation[2] ?? 0] as [
+        number,
+        number,
+        number,
+      ])
+    : typeof currentRotation === 'number'
+      ? liveTransform.rotation
+      : currentRotation
+
+  return {
+    ...(node as Record<string, unknown>),
+    position: liveTransform.position,
+    ...(rotation !== undefined ? { rotation } : {}),
+  } as AnyNode
+}
+
 /**
  * Generic floor-elevation system.
  *
@@ -25,11 +53,12 @@ import type * as THREE from 'three'
  *
  * Runs at priority 1 — before the priority-2 systems (`GeometrySystem`,
  * `ItemSystem`) so the dirty mark survives long enough for those to do
- * their own work. Doesn't clear dirty; the per-kind system (or the
- * generic geometry rebuild) is responsible for that.
+ * their own work. Kinds with no geometry/system have no downstream dirty
+ * consumer, so this system clears their dirty mark after applying the lift.
  */
 export const FloorElevationSystem = () => {
   const dirtyNodes = useScene((s) => s.dirtyNodes)
+  const clearDirty = useScene((s) => s.clearDirty)
 
   useFrame(() => {
     if (dirtyNodes.size === 0) return
@@ -43,31 +72,31 @@ export const FloorElevationSystem = () => {
       const floorPlaced = def?.capabilities?.floorPlaced
       if (!floorPlaced) return
 
-      if (floorPlaced.applies && !floorPlaced.applies(node as AnyNode)) return
-
-      // Only nodes parented directly to a level get the lift. Children of
-      // walls / ceilings / other items inherit Y from the parent group.
-      const parentId = node.parentId as AnyNodeId | null
-      const parent = parentId ? nodes[parentId] : null
-      if (parent && parent.type !== 'level') return
-
       const mesh = sceneRegistry.nodes.get(id) as THREE.Object3D | undefined
       if (!mesh) return
 
-      const position = (node as { position?: [number, number, number] }).position
+      const effectiveNode = withLiveTransform(getEffectiveNode(node as AnyNode), id)
+      const position = (effectiveNode as PositionedNode).position
       if (!position) return
 
-      const levelId = resolveLevelId(node, nodes)
-      if (!levelId) return
-
-      const { dimensions, rotation } = floorPlaced.footprint(node as AnyNode)
-      const slabElevation = spatialGridManager.getSlabElevationForItem(
-        levelId,
+      // This system is the single drag-time authority for floor-stack mesh Y:
+      // tools publish base positions to live stores, renderers may
+      // reconcile that base Y onto the group, then this presentation system
+      // reapplies the resolver-derived visual Y before render. Because the
+      // override/store position remains base-height, the slab lift is never
+      // committed or applied twice.
+      const resolverNodes =
+        effectiveNode === node ? nodes : { ...nodes, [effectiveNode.id]: effectiveNode }
+      const visualPosition = getFloorStackedPosition({
+        node: effectiveNode,
+        nodes: resolverNodes,
         position,
-        dimensions,
-        rotation,
-      )
-      mesh.position.y = slabElevation + position[1]
+      })
+      mesh.position.y = visualPosition[1]
+
+      if (!(def.geometry || def.system)) {
+        clearDirty(id as AnyNodeId)
+      }
     })
   }, 1)
 

packages/viewer/src/systems/stair/stair-system.tsx

@@ -2,11 +2,10 @@ import {
   type AnyNode,
   type AnyNodeId,
   getEffectiveNode,
-  resolveLevelId,
+  getFloorStackedPosition,
   type StairNode,
   type StairSegmentNode,
   sceneRegistry,
-  spatialGridManager,
   useScene,
 } from '@pascal-app/core'
 import { useFrame } from '@react-three/fiber'
@@ -96,9 +95,9 @@ export const StairSystem = () => {
       // so slab-elevation spatial queries match where the segments are
       // actually being rendered. Without this, dragging the rotate gizmo
       // looks up slabs at the pre-drag world XZ — if rotation carries a
-      // segment off the original slab footprint, getStairSlabElevation
-      // returns 0 and `group.position.y` collapses, dropping the flight
-      // or landing below the floor and out of view mid-drag.
+      // segment off the original slab footprint, the floor-stack
+      // resolver would otherwise read the pre-drag footprint and drop
+      // the flight or landing below the floor mid-drag.
       const stairNode = getEffectiveNode(baseStairNode as StairNode)
       const group = sceneRegistry.nodes.get(stairId) as THREE.Group | undefined
       if (group) {
@@ -273,57 +272,20 @@ function syncStairGroupElevation(
   group: THREE.Group,
   nodes: Record<string, AnyNode>,
 ) {
-  const levelId = resolveLevelId(stairNode, nodes)
-  const slabElevation = getStairSlabElevation(levelId, stairNode, nodes)
-  group.position.y = stairNode.position[1] + slabElevation
-}
-
-function getStairSlabElevation(
-  levelId: string,
-  stairNode: StairNode,
-  nodes: Record<string, AnyNode>,
-): number {
-  // Merge live overrides so slab queries match the visual chain during a drag.
-  const segments = (stairNode.children ?? [])
-    .map((childId) => nodes[childId as AnyNodeId] as StairSegmentNode | undefined)
-    .filter((n): n is StairSegmentNode => n?.type === 'stair-segment')
-    .map((n) => getEffectiveNode(n))
-
-  if (segments.length === 0) return 0
-
-  const transforms = computeSegmentTransforms(segments)
-  let maxElevation = Number.NEGATIVE_INFINITY
-
-  for (let i = 0; i < segments.length; i++) {
-    const segment = segments[i]!
-    const transform = transforms[i]!
-
-    const [centerOffsetX, centerOffsetZ] = rotateXZ(0, segment.length / 2, transform.rotation)
-    const centerInGroupX = transform.position[0] + centerOffsetX
-    const centerInGroupZ = transform.position[2] + centerOffsetZ
-    const [centerOffsetWorldX, centerOffsetWorldZ] = rotateXZ(
-      centerInGroupX,
-      centerInGroupZ,
-      stairNode.rotation,
-    )
-
-    const slabElevation = spatialGridManager.getSlabElevationForItem(
-      levelId,
-      [
-        stairNode.position[0] + centerOffsetWorldX,
-        stairNode.position[1] + transform.position[1],
-        stairNode.position[2] + centerOffsetWorldZ,
-      ],
-      [segment.width, Math.max(segment.height, segment.thickness, 0.01), segment.length],
-      [0, stairNode.rotation + transform.rotation, 0],
-    )
-
-    if (slabElevation > maxElevation) {
-      maxElevation = slabElevation
+  const effectiveNodes: Record<string, AnyNode> = { ...nodes, [stairNode.id]: stairNode }
+  for (const childId of stairNode.children ?? []) {
+    const segment = nodes[childId as AnyNodeId]
+    if (segment?.type === 'stair-segment') {
+      effectiveNodes[segment.id] = getEffectiveNode(segment as StairSegmentNode)
     }
   }
-
-  return maxElevation === Number.NEGATIVE_INFINITY ? 0 : maxElevation
+  const visualPosition = getFloorStackedPosition({
+    node: stairNode,
+    nodes: effectiveNodes,
+    position: stairNode.position,
+    rotation: stairNode.rotation,
+  })
+  group.position.y = visualPosition[1]
 }
 
 // ============================================================================