Use mesh bounds for item placement and floorplan

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

@@ -1,5 +1,8 @@
 import type { AnyNode, CeilingNode, ItemNode, SlabNode, WallNode } from '../../schema'
 import { getScaledDimensions } from '../../schema'
+import { sceneRegistry } from '../scene-registry/scene-registry'
+import useScene from '../../store/use-scene'
+import { Box3, Matrix4, Vector3, type Object3D } from 'three'
 import { SpatialGrid } from './spatial-grid'
 import { WallSpatialGrid } from './wall-spatial-grid'
 
@@ -51,6 +54,155 @@ function getItemFootprint(
   ]
 }
 
+type ItemLocalBounds = {
+  min: [number, number, number]
+  max: [number, number, number]
+}
+
+type ItemParentAabb = {
+  minX: number
+  maxX: number
+  minY: number
+  maxY: number
+  minZ: number
+  maxZ: number
+}
+
+function getFallbackItemLocalBounds(item: ItemNode): ItemLocalBounds {
+  const [width, height, depth] = getScaledDimensions(item)
+  const minZ = item.asset.attachTo === 'wall-side' ? -depth : -depth / 2
+  const maxZ = item.asset.attachTo === 'wall-side' ? 0 : depth / 2
+  return {
+    min: [-width / 2, 0, minZ],
+    max: [width / 2, height, maxZ],
+  }
+}
+
+function getItemLocalBoundsFromObject(object: Object3D | null): ItemLocalBounds | null {
+  if (!object) return null
+
+  object.updateWorldMatrix(true, true)
+
+  const inverseRootMatrix = new Matrix4().copy(object.matrixWorld).invert()
+  const localMatrix = new Matrix4()
+  const localBounds = new Box3()
+  const scratchBounds = new Box3()
+  let hasBounds = false
+  const registeredNodeObjects = new Set(sceneRegistry.nodes.values())
+
+  const expandBounds = (child: Object3D) => {
+    if (child !== object && registeredNodeObjects.has(child)) return
+
+    const mesh = child as Object3D & {
+      isMesh?: boolean
+      name?: string
+      geometry?: {
+        boundingBox: Box3 | null
+        computeBoundingBox?: () => void
+      }
+    }
+
+    if (mesh.isMesh && mesh.name !== 'cutout' && mesh.geometry) {
+      if (!mesh.geometry.boundingBox && mesh.geometry.computeBoundingBox) {
+        mesh.geometry.computeBoundingBox()
+      }
+
+      if (mesh.geometry.boundingBox) {
+        localMatrix.copy(inverseRootMatrix).multiply(mesh.matrixWorld)
+        scratchBounds.copy(mesh.geometry.boundingBox).applyMatrix4(localMatrix)
+        if (!hasBounds) {
+          localBounds.copy(scratchBounds)
+          hasBounds = true
+        } else {
+          localBounds.union(scratchBounds)
+        }
+      }
+    }
+
+    for (const grandchild of child.children) {
+      expandBounds(grandchild)
+    }
+  }
+
+  for (const child of object.children) {
+    expandBounds(child)
+  }
+
+  if (!hasBounds) return null
+
+  return {
+    min: [localBounds.min.x, localBounds.min.y, localBounds.min.z],
+    max: [localBounds.max.x, localBounds.max.y, localBounds.max.z],
+  }
+}
+
+function getItemLocalBounds(item: ItemNode): ItemLocalBounds {
+  return getItemLocalBoundsFromObject(sceneRegistry.nodes.get(item.id) ?? null) ?? getFallbackItemLocalBounds(item)
+}
+
+function getItemParentAabb(item: ItemNode): ItemParentAabb {
+  const object = sceneRegistry.nodes.get(item.id)
+  const bounds = getItemLocalBounds(item)
+
+  if (!object) {
+    return {
+      minX: bounds.min[0] + item.position[0],
+      maxX: bounds.max[0] + item.position[0],
+      minY: bounds.min[1] + item.position[1],
+      maxY: bounds.max[1] + item.position[1],
+      minZ: bounds.min[2] + item.position[2],
+      maxZ: bounds.max[2] + item.position[2],
+    }
+  }
+
+  object.updateMatrix()
+  const corners = [
+    new Vector3(bounds.min[0], bounds.min[1], bounds.min[2]),
+    new Vector3(bounds.min[0], bounds.min[1], bounds.max[2]),
+    new Vector3(bounds.min[0], bounds.max[1], bounds.min[2]),
+    new Vector3(bounds.min[0], bounds.max[1], bounds.max[2]),
+    new Vector3(bounds.max[0], bounds.min[1], bounds.min[2]),
+    new Vector3(bounds.max[0], bounds.min[1], bounds.max[2]),
+    new Vector3(bounds.max[0], bounds.max[1], bounds.min[2]),
+    new Vector3(bounds.max[0], bounds.max[1], bounds.max[2]),
+  ]
+
+  let minX = Number.POSITIVE_INFINITY
+  let minY = Number.POSITIVE_INFINITY
+  let minZ = Number.POSITIVE_INFINITY
+  let maxX = Number.NEGATIVE_INFINITY
+  let maxY = Number.NEGATIVE_INFINITY
+  let maxZ = Number.NEGATIVE_INFINITY
+
+  for (const corner of corners) {
+    corner.applyMatrix4(object.matrix)
+    minX = Math.min(minX, corner.x)
+    minY = Math.min(minY, corner.y)
+    minZ = Math.min(minZ, corner.z)
+    maxX = Math.max(maxX, corner.x)
+    maxY = Math.max(maxY, corner.y)
+    maxZ = Math.max(maxZ, corner.z)
+  }
+
+  return { minX, maxX, minY, maxY, minZ, maxZ }
+}
+
+function intervalsOverlap(minA: number, maxA: number, minB: number, maxB: number, epsilon = 1e-4) {
+  return minA < maxB - epsilon && maxA > minB + epsilon
+}
+
+function resolveNodeLevelId(node: AnyNode, nodes: Record<string, AnyNode>): string {
+  if (node.type === 'level') return node.id
+
+  let current: AnyNode | undefined = node
+  while (current) {
+    if (current.type === 'level') return current.id
+    current = current.parentId ? nodes[current.parentId] : undefined
+  }
+
+  return 'default'
+}
+
 /**
  * Test if two line segments (a1->a2) and (b1->b2) intersect.
  */
@@ -481,8 +633,39 @@ export class SpatialGridManager {
     rotation: [number, number, number],
     ignoreIds?: string[],
   ) {
-    const grid = this.getFloorGrid(levelId)
+    const nodes = useScene.getState().nodes
-    return grid.canPlace(position, dimensions, rotation, ignoreIds)
+    const ignoreSet = new Set(ignoreIds ?? [])
+    const [width, , depth] = dimensions
+    const yRot = rotation[1]
+    const cos = Math.abs(Math.cos(yRot))
+    const sin = Math.abs(Math.sin(yRot))
+    const rotatedW = width * cos + depth * sin
+    const rotatedD = width * sin + depth * cos
+    const draftBounds = {
+      minX: position[0] - rotatedW / 2,
+      maxX: position[0] + rotatedW / 2,
+      minZ: position[2] - rotatedD / 2,
+      maxZ: position[2] + rotatedD / 2,
+    }
+
+    const conflicts: string[] = []
+    for (const node of Object.values(nodes)) {
+      if (node.type !== 'item') continue
+      const item = node as ItemNode
+      if (item.asset.attachTo) continue
+      if (ignoreSet.has(item.id)) continue
+      if (resolveNodeLevelId(item, nodes) !== levelId) continue
+
+      const bounds = getItemParentAabb(item)
+      if (
+        intervalsOverlap(draftBounds.minX, draftBounds.maxX, bounds.minX, bounds.maxX) &&
+        intervalsOverlap(draftBounds.minZ, draftBounds.maxZ, bounds.minZ, bounds.maxZ)
+      ) {
+        conflicts.push(item.id)
+      }
+    }
+
+    return { valid: conflicts.length === 0, conflictIds: conflicts }
   }
 
   /**
@@ -514,7 +697,7 @@ export class SpatialGridManager {
     // Convert local X position to parametric t (0-1)
     const tCenter = localX / wallLength
     const [itemWidth, itemHeight] = dimensions
-    return this.getWallGrid(levelId).canPlaceOnWall(
+    const baseResult = this.getWallGrid(levelId).canPlaceOnWall(
       wallId,
       wallLength,
       wallHeight,
@@ -526,6 +709,44 @@ export class SpatialGridManager {
       side,
       ignoreIds,
     )
+
+    if (!baseResult.valid) return baseResult
+
+    const nodes = useScene.getState().nodes
+    const ignoreSet = new Set(ignoreIds ?? [])
+    const draftBounds = {
+      minX: localX - itemWidth / 2,
+      maxX: localX + itemWidth / 2,
+      minY: baseResult.adjustedY,
+      maxY: baseResult.adjustedY + itemHeight,
+    }
+
+    const conflicts: string[] = []
+    for (const node of Object.values(nodes)) {
+      if (node.type !== 'item') continue
+      const item = node as ItemNode
+      if (!(item.asset.attachTo === 'wall' || item.asset.attachTo === 'wall-side')) continue
+      if (ignoreSet.has(item.id)) continue
+      if (item.parentId !== wallId) continue
+
+      if (attachType === 'wall-side' && item.asset.attachTo === 'wall-side' && side && item.side) {
+        if (side !== item.side) continue
+      }
+
+      const bounds = getItemParentAabb(item)
+      if (
+        intervalsOverlap(draftBounds.minX, draftBounds.maxX, bounds.minX, bounds.maxX) &&
+        intervalsOverlap(draftBounds.minY, draftBounds.maxY, bounds.minY, bounds.maxY)
+      ) {
+        conflicts.push(item.id)
+      }
+    }
+
+    return {
+      ...baseResult,
+      valid: conflicts.length === 0,
+      conflictIds: conflicts,
+    }
   }
 
   getWallForItem(levelId: string, itemId: string): string | undefined {
@@ -692,8 +913,39 @@ export class SpatialGridManager {
       }
     }
 
-    // Check for overlaps with other ceiling items
+    const nodes = useScene.getState().nodes
-    return this.getCeilingGrid(ceilingId).canPlace(position, dimensions, rotation, ignoreIds)
+    const ignoreSet = new Set(ignoreIds ?? [])
+    const [width, , depth] = dimensions
+    const yRot = rotation[1]
+    const cos = Math.abs(Math.cos(yRot))
+    const sin = Math.abs(Math.sin(yRot))
+    const rotatedW = width * cos + depth * sin
+    const rotatedD = width * sin + depth * cos
+    const draftBounds = {
+      minX: position[0] - rotatedW / 2,
+      maxX: position[0] + rotatedW / 2,
+      minZ: position[2] - rotatedD / 2,
+      maxZ: position[2] + rotatedD / 2,
+    }
+
+    const conflicts: string[] = []
+    for (const node of Object.values(nodes)) {
+      if (node.type !== 'item') continue
+      const item = node as ItemNode
+      if (item.asset.attachTo !== 'ceiling') continue
+      if (ignoreSet.has(item.id)) continue
+      if (item.parentId !== ceilingId) continue
+
+      const bounds = getItemParentAabb(item)
+      if (
+        intervalsOverlap(draftBounds.minX, draftBounds.maxX, bounds.minX, bounds.maxX) &&
+        intervalsOverlap(draftBounds.minZ, draftBounds.maxZ, bounds.minZ, bounds.maxZ)
+      ) {
+        conflicts.push(item.id)
+      }
+    }
+
+    return { valid: conflicts.length === 0, conflictIds: conflicts }
   }
 
   clearLevel(levelId: string) {

packages/editor/src/components/editor/floorplan-panel.tsx

@@ -449,6 +449,7 @@ type FloorplanItemEntry = {
   item: ItemNode
   points: string
   polygon: Point2D[]
+  usesRealMesh: boolean
 }
 
 type FloorplanStairSegmentEntry = {
@@ -6165,10 +6166,12 @@ export function FloorplanPanel() {
           item: entry.item,
           points: formatPolygonPoints(entry.polygon),
           polygon: entry.polygon,
+          usesRealMesh: entry.usesRealMesh,
         },
       ]
     })
   }, [cursorPoint, floorplanItems, levelDescendantNodeById, movingFloorplanNodeRevision])
+  const hasPendingItemMeshFootprints = floorplanItemEntries.some((entry) => !entry.usesRealMesh)
   const floorplanStairEntries = useMemo(
     () =>
       floorplanStairs.flatMap((stair) => {
@@ -8044,6 +8047,20 @@ export function FloorplanPanel() {
     }
   }, [isItemPlacementPreviewActive])
 
+  useEffect(() => {
+    if (!hasPendingItemMeshFootprints) {
+      return
+    }
+
+    const frameId = window.requestAnimationFrame(() => {
+      setMovingFloorplanNodeRevision((current) => current + 1)
+    })
+
+    return () => {
+      window.cancelAnimationFrame(frameId)
+    }
+  }, [hasPendingItemMeshFootprints])
+
   useEffect(() => {
     if (!(movingNode?.type === 'door' || movingNode?.type === 'window')) {
       return

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

@@ -20,11 +20,14 @@ import { useFrame } from '@react-three/fiber'
 import { useEffect, useRef } from 'react'
 import {
   BoxGeometry,
+  Box3,
   EdgesGeometry,
   Euler,
   type Group,
   type LineSegments,
+  Matrix4,
   type Mesh,
+  type Object3D,
   PlaneGeometry,
   Quaternion,
   Vector3,
@@ -46,6 +49,108 @@ import type { DraftNodeHandle } from './use-draft-node'
 
 const DEFAULT_DIMENSIONS: [number, number, number] = [1, 1, 1]
 
+type PreviewBounds = {
+  min: [number, number, number]
+  max: [number, number, number]
+  dimensions: [number, number, number]
+  center: [number, number, number]
+}
+
+function getPreviewBoundsFromObject(object: Object3D | null): PreviewBounds | null {
+  if (!object) return null
+
+  object.updateWorldMatrix(true, true)
+
+  const inverseRootMatrix = new Matrix4().copy(object.matrixWorld).invert()
+  const localMatrix = new Matrix4()
+  const localBounds = new Box3()
+  const scratchBounds = new Box3()
+  const hasBounds = { current: false }
+  const registeredNodeObjects = new Set(sceneRegistry.nodes.values())
+
+  const expandBounds = (child: Object3D) => {
+    if (child !== object && registeredNodeObjects.has(child)) {
+      return
+    }
+
+    const mesh = child as Object3D & {
+      isMesh?: boolean
+      name?: string
+      geometry?: {
+        boundingBox: Box3 | null
+        computeBoundingBox?: () => void
+      }
+    }
+
+    if (mesh.isMesh && mesh.name !== 'cutout' && mesh.geometry) {
+      if (!mesh.geometry.boundingBox && mesh.geometry.computeBoundingBox) {
+        mesh.geometry.computeBoundingBox()
+      }
+
+      if (mesh.geometry.boundingBox) {
+        localMatrix.copy(inverseRootMatrix).multiply(mesh.matrixWorld)
+        scratchBounds.copy(mesh.geometry.boundingBox).applyMatrix4(localMatrix)
+        if (Number.isFinite(scratchBounds.min.x) && Number.isFinite(scratchBounds.max.x)) {
+          if (!hasBounds.current) {
+            localBounds.copy(scratchBounds)
+            hasBounds.current = true
+          } else {
+            localBounds.union(scratchBounds)
+          }
+        }
+      }
+    }
+
+    for (const grandchild of child.children) {
+      expandBounds(grandchild)
+    }
+  }
+
+  for (const child of object.children) {
+    expandBounds(child)
+  }
+
+  if (!hasBounds.current) return null
+
+  const size = new Vector3()
+  const center = new Vector3()
+  localBounds.getSize(size)
+  localBounds.getCenter(center)
+
+  if (size.x <= 0 || size.y <= 0 || size.z <= 0) {
+    return null
+  }
+
+  return {
+    min: [localBounds.min.x, localBounds.min.y, localBounds.min.z],
+    max: [localBounds.max.x, localBounds.max.y, localBounds.max.z],
+    dimensions: [size.x, size.y, size.z],
+    center: [center.x, center.y, center.z],
+  }
+}
+
+function getFallbackPreviewBounds(
+  item: import('@pascal-app/core').ItemNode | null,
+  asset: AssetInput,
+  attachTo: AssetInput['attachTo'],
+): PreviewBounds {
+  const dims = item ? getScaledDimensions(item) : (asset.dimensions ?? DEFAULT_DIMENSIONS)
+  return {
+    min: [
+      -dims[0] / 2,
+      0,
+      attachTo === 'wall-side' ? -dims[2] : -dims[2] / 2,
+    ],
+    max: [
+      dims[0] / 2,
+      dims[1],
+      attachTo === 'wall-side' ? 0 : dims[2] / 2,
+    ],
+    dimensions: dims,
+    center: [0, dims[1] / 2, attachTo === 'wall-side' ? -dims[2] / 2 : 0],
+  }
+}
+
 // 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({
@@ -89,6 +194,8 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
     config.initialState ?? { surface: 'floor', wallId: null, ceilingId: null, surfaceItemId: null },
   )
   const shiftFreeRef = useRef(false)
+  const previewBoundsSignatureRef = useRef<string | null>(null)
+  const meshPreviewAppliedRef = useRef(false)
 
   // Store config callbacks in refs to avoid re-running effect when they change
   const configRef = useRef(config)
@@ -97,9 +204,33 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
   const { canPlaceOnFloor, canPlaceOnWall, canPlaceOnCeiling } = useSpatialQuery()
   const { asset, draftNode } = config
 
+  const updatePreviewGeometry = (bounds: PreviewBounds) => {
+    const [width, height, depth] = bounds.dimensions
+    const [centerX, centerY, centerZ] = bounds.center
+    const signature = `${width.toFixed(4)}:${height.toFixed(4)}:${depth.toFixed(4)}:${centerX.toFixed(4)}:${centerY.toFixed(4)}:${centerZ.toFixed(4)}`
+
+    if (previewBoundsSignatureRef.current === signature) return
+    previewBoundsSignatureRef.current = signature
+
+    const nextBoxGeometry = new BoxGeometry(width, height, depth)
+    nextBoxGeometry.translate(centerX, centerY, centerZ)
+    const nextEdgesGeometry = new EdgesGeometry(nextBoxGeometry)
+
+    const nextBasePlaneGeometry = new PlaneGeometry(width, depth)
+    nextBasePlaneGeometry.rotateX(-Math.PI / 2)
+    nextBasePlaneGeometry.translate(centerX, 0.01, centerZ)
+
+    edgesRef.current.geometry.dispose()
+    edgesRef.current.geometry = nextEdgesGeometry
+    basePlaneRef.current.geometry.dispose()
+    basePlaneRef.current.geometry = nextBasePlaneGeometry
+    nextBoxGeometry.dispose()
+  }
+
   useEffect(() => {
     if (!asset) return
     useScene.temporal.getState().pause()
+    meshPreviewAppliedRef.current = false
 
     const validators = { canPlaceOnFloor, canPlaceOnWall, canPlaceOnCeiling }
 
@@ -825,12 +956,13 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
     // ---- Bounding box geometry ----
 
     const draft = draftNode.current
-    const dims = draft ? getScaledDimensions(draft) : (asset.dimensions ?? DEFAULT_DIMENSIONS)
+    const fallbackBounds = getFallbackPreviewBounds(draft, asset, asset.attachTo)
-    const boxGeometry = new BoxGeometry(dims[0], dims[1], dims[2])
+    updatePreviewGeometry(
-    const wallSideZOffset = asset.attachTo === 'wall-side' ? -dims[2] / 2 : 0
+      draft
-    boxGeometry.translate(0, dims[1] / 2, wallSideZOffset)
+        ? (getPreviewBoundsFromObject(sceneRegistry.nodes.get(draft.id) ?? null) ??
-    const edgesGeometry = new EdgesGeometry(boxGeometry)
+          fallbackBounds)
-    edgesRef.current.geometry = edgesGeometry
+        : fallbackBounds,
+    )
 
     // ---- Undo protection ----
     // Undo replaces the entire `nodes` object with a previous snapshot, which doesn't
@@ -874,6 +1006,7 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
 
     return () => {
       tearingDown = true
+      meshPreviewAppliedRef.current = false
       unsubDraftWatch()
       // Clear live transform for any remaining draft
       if (draftNode.current) {
@@ -920,6 +1053,14 @@ export function usePlacementCoordinator(config: PlacementCoordinatorConfig): Rea
     const mesh = sceneRegistry.nodes.get(draftNode.current.id)
     if (!mesh) return
 
+    if (!meshPreviewAppliedRef.current) {
+      const previewBounds = getPreviewBoundsFromObject(mesh)
+      if (previewBounds) {
+        updatePreviewGeometry(previewBounds)
+        meshPreviewAppliedRef.current = true
+      }
+    }
+
     // Hide wall/ceiling-attached items when between surfaces (only cursor visible)
     if (asset.attachTo && placementState.current.surface === 'floor') {
       mesh.visible = false

packages/editor/src/lib/floorplan/items.ts

@@ -1,12 +1,14 @@
 import {
-  getScaledDimensions,
   type AnyNode,
   type AnyNodeId,
   type ItemNode,
   type LevelNode,
+  sceneRegistry,
   useLiveTransforms,
 } from '@pascal-app/core'
-import { getRotatedRectanglePolygon, rotatePlanVector } from './geometry'
+import type { Object3D } from 'three'
+import { Box3, Matrix4, Vector3 } from 'three'
+import { rotatePlanVector } from './geometry'
 import type { FloorplanItemEntry, FloorplanNodeTransform, LevelDescendantMap } from './types'
 
 export function collectLevelDescendants(
@@ -136,9 +138,253 @@ export function buildFloorplanItemEntry(
     return null
   }
 
-  const [width, , depth] = getScaledDimensions(item)
+  const object = sceneRegistry.nodes.get(item.id)
+  const realMeshPolygon = object
+    ? getRealMeshFloorplanPolygon(transform, object)
+    : getCachedMeshFloorplanPolygon(item, transform)
+  if (!realMeshPolygon) {
+    return null
+  }
+
   return {
     item,
-    polygon: getRotatedRectanglePolygon(transform.position, width, depth, transform.rotation),
+    polygon: realMeshPolygon,
+    usesRealMesh: realMeshPolygon !== null,
   }
 }
+
+type Point = {
+  x: number
+  y: number
+}
+
+function getCachedLocalMeshPolygon(item: ItemNode): Point[] | null {
+  const metadata =
+    typeof item.metadata === 'object' && item.metadata !== null && !Array.isArray(item.metadata)
+      ? (item.metadata as Record<string, unknown>)
+      : null
+  const rawPolygon = metadata?.floorplanLocalPolygon
+  if (!Array.isArray(rawPolygon)) {
+    return null
+  }
+
+  const polygon = rawPolygon.flatMap((point) => {
+    if (!Array.isArray(point) || point.length < 2) {
+      return []
+    }
+    const x = point[0]
+    const y = point[1]
+    return typeof x === 'number' && typeof y === 'number' ? [{ x, y }] : []
+  })
+
+  return polygon.length >= 3 ? polygon : null
+}
+
+function getCachedMeshFloorplanPolygon(item: ItemNode, transform: FloorplanNodeTransform) {
+  const localPolygon = getCachedLocalMeshPolygon(item)
+  if (!localPolygon) {
+    return null
+  }
+
+  return localPolygon.map((corner) => {
+    const [offsetX, offsetY] = rotatePlanVector(corner.x, corner.y, transform.rotation)
+    return {
+      x: transform.position.x + offsetX,
+      y: transform.position.y + offsetY,
+    }
+  })
+}
+
+function getRealMeshFloorplanPolygon(transform: FloorplanNodeTransform, object: Object3D) {
+  const localPolygon = getLocalMeshFloorplanPolygon(object)
+  if (localPolygon.length === 0) {
+    return null
+  }
+
+  return localPolygon.map((corner) => {
+    const [offsetX, offsetY] = rotatePlanVector(corner.x, corner.y, transform.rotation)
+    return {
+      x: transform.position.x + offsetX,
+      y: transform.position.y + offsetY,
+    }
+  })
+}
+
+function getLocalMeshFloorplanPolygon(object: Object3D): Point[] {
+  object.updateWorldMatrix(true, true)
+
+  const inverseRootMatrix = new Matrix4().copy(object.matrixWorld).invert()
+  const localMatrix = new Matrix4()
+  const scratchBounds = new Box3()
+  const scratchPosition = new Vector3()
+  const registeredNodeObjects = new Set(sceneRegistry.nodes.values())
+  const footprintPoints: Point[] = []
+
+  const collectPoints = (child: Object3D) => {
+    if (child !== object && registeredNodeObjects.has(child)) {
+      return
+    }
+
+    const mesh = child as {
+      isMesh?: boolean
+      name?: string
+      geometry?: {
+        boundingBox: Box3 | null
+        computeBoundingBox?: () => void
+        attributes?: {
+          position?: {
+            count: number
+            getX: (index: number) => number
+            getY: (index: number) => number
+            getZ: (index: number) => number
+          }
+        }
+      }
+      matrixWorld: Matrix4
+    }
+
+    if (mesh.isMesh && mesh.name !== 'cutout' && mesh.geometry) {
+      if (!mesh.geometry.boundingBox && mesh.geometry.computeBoundingBox) {
+        mesh.geometry.computeBoundingBox()
+      }
+
+      localMatrix.copy(inverseRootMatrix).multiply(mesh.matrixWorld)
+
+      const vertexPositions = mesh.geometry.attributes?.position
+      if (vertexPositions && vertexPositions.count > 0) {
+        for (let index = 0; index < vertexPositions.count; index += 1) {
+          scratchPosition
+            .set(
+              vertexPositions.getX(index),
+              vertexPositions.getY(index),
+              vertexPositions.getZ(index),
+            )
+            .applyMatrix4(localMatrix)
+
+          if (Number.isFinite(scratchPosition.x) && Number.isFinite(scratchPosition.z)) {
+            footprintPoints.push({ x: scratchPosition.x, y: scratchPosition.z })
+          }
+        }
+      } else if (mesh.geometry.boundingBox) {
+        scratchBounds.copy(mesh.geometry.boundingBox)
+        scratchBounds.applyMatrix4(localMatrix)
+        if (Number.isFinite(scratchBounds.min.x) && Number.isFinite(scratchBounds.max.x)) {
+          footprintPoints.push(
+            { x: scratchBounds.min.x, y: scratchBounds.min.z },
+            { x: scratchBounds.max.x, y: scratchBounds.min.z },
+            { x: scratchBounds.max.x, y: scratchBounds.max.z },
+            { x: scratchBounds.min.x, y: scratchBounds.max.z },
+          )
+        }
+      }
+    }
+
+    for (const grandchild of child.children) {
+      collectPoints(grandchild)
+    }
+  }
+
+  for (const child of object.children) {
+    collectPoints(child)
+  }
+
+  return getMinimumAreaBoundingRect(footprintPoints) ?? []
+}
+
+function getMinimumAreaBoundingRect(points: Point[]) {
+  if (points.length === 0) {
+    return null
+  }
+
+  const hull = getConvexHull(points)
+  if (hull.length === 0) {
+    return null
+  }
+
+  if (hull.length === 1) {
+    const point = hull[0]!
+    return [point, point, point, point]
+  }
+
+  if (hull.length === 2) {
+    const [start, end] = hull
+    return [start!, end!, end!, start!]
+  }
+
+  let bestArea = Number.POSITIVE_INFINITY
+  let bestRect: Point[] | null = null
+
+  for (let index = 0; index < hull.length; index += 1) {
+    const start = hull[index]!
+    const end = hull[(index + 1) % hull.length]!
+    const angle = Math.atan2(end.y - start.y, end.x - start.x)
+    const cos = Math.cos(-angle)
+    const sin = Math.sin(-angle)
+
+    let minX = Number.POSITIVE_INFINITY
+    let maxX = Number.NEGATIVE_INFINITY
+    let minY = Number.POSITIVE_INFINITY
+    let maxY = Number.NEGATIVE_INFINITY
+
+    for (const point of hull) {
+      const rx = point.x * cos - point.y * sin
+      const ry = point.x * sin + point.y * cos
+      minX = Math.min(minX, rx)
+      maxX = Math.max(maxX, rx)
+      minY = Math.min(minY, ry)
+      maxY = Math.max(maxY, ry)
+    }
+
+    const area = (maxX - minX) * (maxY - minY)
+    if (area >= bestArea) {
+      continue
+    }
+
+    bestRect = [
+      { x: minX, y: minY },
+      { x: maxX, y: minY },
+      { x: maxX, y: maxY },
+      { x: minX, y: maxY },
+    ].map((point) => ({
+      x: point.x * Math.cos(angle) - point.y * Math.sin(angle),
+      y: point.x * Math.sin(angle) + point.y * Math.cos(angle),
+    }))
+    bestArea = area
+  }
+
+  return bestRect
+}
+
+function getConvexHull(points: Point[]) {
+  const uniquePoints = Array.from(
+    new Map(points.map((point) => [`${point.x.toFixed(6)}:${point.y.toFixed(6)}`, point])).values(),
+  ).sort((a, b) => (a.x === b.x ? a.y - b.y : a.x - b.x))
+
+  if (uniquePoints.length <= 1) {
+    return uniquePoints
+  }
+
+  const cross = (origin: Point, a: Point, b: Point) =>
+    (a.x - origin.x) * (b.y - origin.y) - (a.y - origin.y) * (b.x - origin.x)
+
+  const lower: Point[] = []
+  for (const point of uniquePoints) {
+    while (lower.length >= 2 && cross(lower[lower.length - 2]!, lower[lower.length - 1]!, point) <= 0) {
+      lower.pop()
+    }
+    lower.push(point)
+  }
+
+  const upper: Point[] = []
+  for (let index = uniquePoints.length - 1; index >= 0; index -= 1) {
+    const point = uniquePoints[index]!
+    while (upper.length >= 2 && cross(upper[upper.length - 2]!, upper[upper.length - 1]!, point) <= 0) {
+      upper.pop()
+    }
+    upper.push(point)
+  }
+
+  lower.pop()
+  upper.pop()
+  return [...lower, ...upper]
+}

packages/editor/src/lib/floorplan/types.ts

@@ -13,6 +13,7 @@ export type FloorplanLineSegment = {
 export type FloorplanItemEntry = {
   item: ItemNode
   polygon: Point2D[]
+  usesRealMesh: boolean
 }
 
 export type FloorplanStairSegmentEntry = {

packages/viewer/src/components/renderers/item/item-renderer.tsx

@@ -15,8 +15,8 @@ import { Clone } from '@react-three/drei/core/Clone'
 import { useGLTF } from '@react-three/drei/core/Gltf'
 import { useFrame } from '@react-three/fiber'
 import { Suspense, useEffect, useMemo, useRef } from 'react'
-import type { AnimationAction, Group, Material, Mesh } from 'three'
+import type { AnimationAction, Group, Material, Mesh, Object3D } from 'three'
-import { MathUtils } from 'three'
+import { Box3, MathUtils, Matrix4, Vector3 } from 'three'
 import { positionLocal, smoothstep, time } from 'three/tsl'
 import { MeshStandardNodeMaterial } from 'three/webgpu'
 import { useNodeEvents } from '../../../hooks/use-node-events'
@@ -89,6 +89,167 @@ const multiplyScales = (
   b: [number, number, number],
 ): [number, number, number] => [a[0] * b[0], a[1] * b[1], a[2] * b[2]]
 
+type Point = {
+  x: number
+  y: number
+}
+
+function getLocalMeshFloorplanPolygon(object: Object3D): Point[] {
+  object.updateWorldMatrix(true, true)
+
+  const inverseRootMatrix = new Matrix4().copy(object.matrixWorld).invert()
+  const localMatrix = new Matrix4()
+  const scratchBounds = new Box3()
+  const scratchPosition = new Vector3()
+  const footprintPoints: Point[] = []
+
+  const collectPoints = (child: Object3D) => {
+    const mesh = child as Object3D & {
+      isMesh?: boolean
+      name?: string
+      geometry?: {
+        boundingBox: Box3 | null
+        computeBoundingBox?: () => void
+        attributes?: {
+          position?: {
+            count: number
+            getX: (index: number) => number
+            getY: (index: number) => number
+            getZ: (index: number) => number
+          }
+        }
+      }
+      matrixWorld: Matrix4
+    }
+
+    if (mesh.isMesh && mesh.name !== 'cutout' && mesh.geometry) {
+      if (!mesh.geometry.boundingBox && mesh.geometry.computeBoundingBox) {
+        mesh.geometry.computeBoundingBox()
+      }
+
+      localMatrix.copy(inverseRootMatrix).multiply(mesh.matrixWorld)
+
+      const vertexPositions = mesh.geometry.attributes?.position
+      if (vertexPositions && vertexPositions.count > 0) {
+        for (let index = 0; index < vertexPositions.count; index += 1) {
+          scratchPosition
+            .set(
+              vertexPositions.getX(index),
+              vertexPositions.getY(index),
+              vertexPositions.getZ(index),
+            )
+            .applyMatrix4(localMatrix)
+
+          if (Number.isFinite(scratchPosition.x) && Number.isFinite(scratchPosition.z)) {
+            footprintPoints.push({ x: scratchPosition.x, y: scratchPosition.z })
+          }
+        }
+      } else if (mesh.geometry.boundingBox) {
+        scratchBounds.copy(mesh.geometry.boundingBox)
+        scratchBounds.applyMatrix4(localMatrix)
+        if (Number.isFinite(scratchBounds.min.x) && Number.isFinite(scratchBounds.max.x)) {
+          footprintPoints.push(
+            { x: scratchBounds.min.x, y: scratchBounds.min.z },
+            { x: scratchBounds.max.x, y: scratchBounds.min.z },
+            { x: scratchBounds.max.x, y: scratchBounds.max.z },
+            { x: scratchBounds.min.x, y: scratchBounds.max.z },
+          )
+        }
+      }
+    }
+
+    for (const grandchild of child.children) {
+      collectPoints(grandchild)
+    }
+  }
+
+  for (const child of object.children) {
+    collectPoints(child)
+  }
+
+  return getMinimumAreaBoundingRect(footprintPoints) ?? []
+}
+
+function getMinimumAreaBoundingRect(points: Point[]) {
+  if (points.length === 0) return null
+  if (points.length < 3) return points
+
+  const hull = getConvexHull(points)
+  if (hull.length < 3) return hull
+
+  let bestArea = Number.POSITIVE_INFINITY
+  let bestRect: Point[] | null = null
+
+  for (let index = 0; index < hull.length; index += 1) {
+    const nextIndex = (index + 1) % hull.length
+    const current = hull[index]!
+    const next = hull[nextIndex]!
+    const angle = Math.atan2(next.y - current.y, next.x - current.x)
+    const cos = Math.cos(-angle)
+    const sin = Math.sin(-angle)
+
+    let minX = Number.POSITIVE_INFINITY
+    let maxX = Number.NEGATIVE_INFINITY
+    let minY = Number.POSITIVE_INFINITY
+    let maxY = Number.NEGATIVE_INFINITY
+
+    for (const point of hull) {
+      const rx = point.x * cos - point.y * sin
+      const ry = point.x * sin + point.y * cos
+      minX = Math.min(minX, rx)
+      maxX = Math.max(maxX, rx)
+      minY = Math.min(minY, ry)
+      maxY = Math.max(maxY, ry)
+    }
+
+    const area = (maxX - minX) * (maxY - minY)
+    if (area >= bestArea) continue
+    bestArea = area
+
+    const unrotate = (x: number, y: number): Point => ({
+      x: x * Math.cos(angle) - y * Math.sin(angle),
+      y: x * Math.sin(angle) + y * Math.cos(angle),
+    })
+
+    bestRect = [
+      unrotate(minX, minY),
+      unrotate(maxX, minY),
+      unrotate(maxX, maxY),
+      unrotate(minX, maxY),
+    ]
+  }
+
+  return bestRect
+}
+
+function getConvexHull(points: Point[]) {
+  if (points.length <= 1) return points
+
+  const sorted = [...points].sort((a, b) => (a.x === b.x ? a.y - b.y : a.x - b.x))
+  const cross = (o: Point, a: Point, b: Point) => (a.x - o.x) * (b.y - o.y) - (a.y - o.y) * (b.x - o.x)
+
+  const lower: Point[] = []
+  for (const point of sorted) {
+    while (lower.length >= 2 && cross(lower[lower.length - 2]!, lower[lower.length - 1]!, point) <= 0) {
+      lower.pop()
+    }
+    lower.push(point)
+  }
+
+  const upper: Point[] = []
+  for (let index = sorted.length - 1; index >= 0; index -= 1) {
+    const point = sorted[index]!
+    while (upper.length >= 2 && cross(upper[upper.length - 2]!, upper[upper.length - 1]!, point) <= 0) {
+      upper.pop()
+    }
+    upper.push(point)
+  }
+
+  lower.pop()
+  upper.pop()
+  return [...lower, ...upper]
+}
+
 const ModelRenderer = ({ node }: { node: ItemNode }) => {
   const { scene, nodes, animations } = useGLTF(resolveCdnUrl(node.asset.src) || '')
   const ref = useRef<Group>(null!)
@@ -107,6 +268,39 @@ const ModelRenderer = ({ node }: { node: ItemNode }) => {
     useScene.getState().dirtyNodes.add(node.parentId as AnyNodeId)
   }, [node.parentId])
 
+  useEffect(() => {
+    const cloneRoot = ref.current
+    if (!cloneRoot) return
+
+    const polygon = getLocalMeshFloorplanPolygon(cloneRoot)
+    if (polygon.length < 3) return
+
+    const nextPolygon = polygon.map(({ x, y }) => [x, y] as [number, number])
+    const metadata =
+      typeof node.metadata === 'object' && node.metadata !== null && !Array.isArray(node.metadata)
+        ? (node.metadata as Record<string, unknown>)
+        : {}
+    const currentPolygon = metadata.floorplanLocalPolygon
+    const unchanged =
+      Array.isArray(currentPolygon) &&
+      currentPolygon.length === nextPolygon.length &&
+      currentPolygon.every(
+        (point, index) =>
+          Array.isArray(point) &&
+          point[0] === nextPolygon[index]?.[0] &&
+          point[1] === nextPolygon[index]?.[1],
+      )
+
+    if (unchanged) return
+
+    useScene.getState().updateNode(node.id, {
+      metadata: {
+        ...metadata,
+        floorplanLocalPolygon: nextPolygon,
+      },
+    })
+  }, [node.id, node.metadata, scene])
+
   useEffect(() => {
     const interactive = interactiveRef.current
     if (!interactive) return