fix(export): unbreak bakes and STL/OBJ exports on malformed/placeholder meshes (#466)

- roof-system: replace BoxGeometry placeholders (initial swap + empty-roof
  merged shell) with a group-less degenerate geometry — a Box's 6 groups
  against the roof's 4-material array crashed GLTFExporter on every scene
  with a segment-less roof node (prod: 'reading isShaderMaterial'), and
  count-0 groups crash MeshBVH's packed-tree build.
- glb-export: sanitizeMaterialGroups pass repairs any mesh whose geometry
  groups don't line up with its material array before GLTFExporter runs.
- export-manager: give neutralised (attribute-less) meshes an empty position
  attribute before STL/OBJ export — both exporters read position.count
  unconditionally.
- bake-exporter: log the full error stack so the bake worker's console relay
  captures it in the job's error trail.
- viewer: host-controlled disablePostFx prop (Viewer → PostProcessing) that
  skips building the SSGI/denoise pipeline entirely; the ?disable=postFx URL
  flag previously only bypassed it per-frame while still allocating it.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

packages/viewer/src/components/viewer/index.tsx

@@ -345,6 +345,14 @@ interface ViewerProps {
    */
   sceneReadyKey?: string | number | null
   onSceneReadyChange?: (ready: boolean) => void
+  /**
+   * Skip the TSL post-processing pipeline (SSGI/denoise/ink/outline) and render
+   * the scene directly. For headless/capture surfaces (the bake page) where
+   * frame quality is irrelevant: on a software-rasterised worker the pipeline
+   * consumes the whole CPU budget and bakes time out. Equivalent to the
+   * `?disable=postFx` diagnostic URL flag, but host-controlled.
+   */
+  disablePostFx?: boolean
 }
 
 /** Imperative handle exposed via `ref` on `<Viewer>`. */
@@ -371,6 +379,7 @@ const Viewer = forwardRef<ViewerHandle, ViewerProps>(function Viewer(
     isolate,
     sceneReadyKey,
     onSceneReadyChange,
+    disablePostFx = false,
   },
   ref,
 ) {
@@ -549,7 +558,7 @@ const Viewer = forwardRef<ViewerHandle, ViewerProps>(function Viewer(
             kind's `def.system` is loaded via lazy() and rendered here,
             ordered by `system.priority`. */}
         <RegisteredSystems />
-        <PostProcessing hoverStyles={hoverStyles} />
+        <PostProcessing disablePostFx={disablePostFx} hoverStyles={hoverStyles} />
         {selectionManager === 'default' && <SelectionManager />}
         {(perf || PERF_OVERLAY_ENABLED) && <PerfMonitor />}
         {children}

packages/viewer/src/components/viewer/post-processing.tsx

@@ -126,8 +126,11 @@ function sanitizeOutlineObjects(objects: Object3D[]) {
 
 const PostProcessingPasses = ({
   hoverStyles = DEFAULT_HOVER_STYLES,
+  disablePostFx = false,
 }: {
   hoverStyles?: HoverStyles
+  /** Host-controlled equivalent of `?disable=postFx` — see the Viewer prop. */
+  disablePostFx?: boolean
 }) => {
   const { gl: renderer, invalidate, scene, camera, size } = useThree()
   const renderPipelineRef = useRef<RenderPipeline | null>(null)
@@ -264,6 +267,19 @@ const PostProcessingPasses = ({
     }
 
     const perfDisable = readPerfDisableFlags()
+
+    // postFx off (host prop or ?disable=postFx): never allocate the pipeline —
+    // useFrame's null-pipeline branch direct-renders. Before this check the
+    // URL flag only skipped the pipeline at render time; the build still
+    // allocated every pass.
+    if (disablePostFx || perfDisable.postFx) {
+      hasPipelineErrorRef.current = false
+      if (renderPipelineRef.current) {
+        renderPipelineRef.current.dispose()
+      }
+      renderPipelineRef.current = null
+      return
+    }
     const ssgiEnabled = shading === 'rendered' && SSGI_PARAMS.enabled && !perfDisable.ao
     const denoiseEnabled = ssgiEnabled && !perfDisable.denoise
     const outlineEnabled = !perfDisable.outline
@@ -521,6 +537,7 @@ const PostProcessingPasses = ({
     // whole pipeline. The uniform refs below are stable (useMemo), so they
     // never trigger a rebuild either.
     camera,
+    disablePostFx,
     hoverHiddenColor,
     hoverPulseMix,
     hoverStrength,
@@ -556,7 +573,12 @@ const PostProcessingPasses = ({
     sanitizeOutlineObjects(outliner.selectedObjects)
     sanitizeOutlineObjects(outliner.hoveredObjects)
 
-    if (PERF_POST_FX_DISABLED || hasPipelineErrorRef.current || !renderPipelineRef.current) {
+    if (
+      disablePostFx ||
+      PERF_POST_FX_DISABLED ||
+      hasPipelineErrorRef.current ||
+      !renderPipelineRef.current
+    ) {
       try {
         if ((renderer as any).setClearAlpha) {
           ;(renderer as any).setClearAlpha(transparentBackground ? 0 : 1)

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

@@ -125,6 +125,28 @@ const _surfaceV1 = new THREE.Vector3()
 const _surfaceV2 = new THREE.Vector3()
 const _surfaceFaceNormal = new THREE.Vector3()
 
+/**
+ * Degenerate placeholder for a roof mesh with nothing to draw (initial
+ * BoxGeometry swap-out, or a roof whose segments were all deleted/painted).
+ * Three zero-vertices (one invisible triangle), not an empty attribute: an
+ * empty position (count 0) leaves WebGPU vertex buffer slot 0 unbound if the
+ * mesh is ever drawn, and computeBoundsTree needs a real position buffer to
+ * index. Deliberately NO groups: count-0 groups crash MeshBVH's packed-tree
+ * build (it partitions roots by group), and a BoxGeometry's 6 groups against
+ * the 4 roof materials crash raycasts and GLTFExporter. Group-less + a
+ * zero-area triangle is safe everywhere — it draws nothing under an array
+ * material and can never be ray-hit.
+ */
+function createDegenerateRoofPlaceholder(): THREE.BufferGeometry {
+  const placeholder = new THREE.BufferGeometry()
+  placeholder.setAttribute('position', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
+  placeholder.setAttribute('normal', new THREE.Float32BufferAttribute(new Float32Array(9), 3))
+  placeholder.setAttribute('uv', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
+  placeholder.setAttribute('uv2', new THREE.Float32BufferAttribute(new Float32Array(6), 2))
+  computeGeometryBoundsTree(placeholder)
+  return placeholder
+}
+
 // Pending merged-roof updates carried across frames (for throttling)
 const pendingRoofUpdates = new Set<AnyNodeId>()
 const warnedMergedRoofNaNIds = new Set<AnyNodeId>()
@@ -219,29 +241,7 @@ export const RoofSystem = () => {
             // so MeshBVH hits groups[4].materialIndex → undefined.side → crash.
             if (mesh.geometry.type === 'BoxGeometry') {
               mesh.geometry.dispose()
-              const placeholder = new THREE.BufferGeometry()
-              // Three zero-vertices (one degenerate, invisible triangle), not an
-              // empty attribute: an empty position (count 0) leaves WebGPU vertex
-              // buffer slot 0 unbound if the mesh is ever drawn, and computeBoundsTree
-              // needs a real position buffer to index.
-              placeholder.setAttribute(
-                'position',
-                new THREE.Float32BufferAttribute(new Float32Array(9), 3),
-              )
-              placeholder.setAttribute(
-                'normal',
-                new THREE.Float32BufferAttribute(new Float32Array(9), 3),
-              )
-              placeholder.setAttribute(
-                'uv',
-                new THREE.Float32BufferAttribute(new Float32Array(6), 2),
-              )
-              placeholder.setAttribute(
-                'uv2',
-                new THREE.Float32BufferAttribute(new Float32Array(6), 2),
-              )
-              computeGeometryBoundsTree(placeholder)
-              mesh.geometry = placeholder
+              mesh.geometry = createDegenerateRoofPlaceholder()
             }
             mesh.position.set(
               effectiveSegment.position[0],
@@ -497,8 +497,9 @@ function updateMergedRoofGeometry(
 
   if (children.length === 0) {
     mergedMesh.geometry.dispose()
-    // Keep a valid position attribute so Drei's BVH can index safely.
-    mergedMesh.geometry = new THREE.BoxGeometry(0, 0, 0)
+    // Not BoxGeometry: its 6 groups against the merged mesh's 4-material array
+    // crash GLTFExporter (materials[4] → undefined) when the roof bakes.
+    mergedMesh.geometry = createDegenerateRoofPlaceholder()
     return
   }