fix: smooth normals on non-indexed geometry + sync DB in gltf task

InlineCadViewer: STL-derived GLBs have non-indexed geometry (unique vertex
per triangle face). computeVertexNormals() on non-indexed geometry produces
per-face normals (faceted shading). Fix: mergeVertices() first to create
shared/indexed geometry, then computeVertexNormals() averages across
adjacent faces → smooth shading. Indexed Blender GLBs are unaffected.

generate_gltf_geometry_task: asyncio.run() inside a Celery worker that
already runs asyncpg causes 'Future attached to a different loop'. Replace
async _store() with sync SQLAlchemy session (matching the rest of the task).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/tasks/step_tasks.py

@@ -530,38 +530,37 @@ def generate_gltf_geometry_task(self, cad_file_id: str):
         log_task_event(self.request.id, f"Blender GLB export completed: {output_path.name}", "done")
 
     # --- Store MediaAsset (replace existing gltf_geometry for this cad_file) ---
-    import asyncio
+    # Use sync SQLAlchemy to avoid asyncio event-loop conflicts in Celery workers.
+    import uuid as _uuid
+    from sqlalchemy import create_engine as _ce, delete as _del
+    from sqlalchemy.orm import Session as _Session
+    from app.domains.media.models import MediaAsset, MediaAssetType
 
-    async def _store():
-        from app.database import AsyncSessionLocal
-        from app.domains.media.models import MediaAsset, MediaAssetType
-        from app.config import settings as _cfg
-        import uuid
-        async with AsyncSessionLocal() as db:
-            # Delete previous gltf_geometry assets for this cad_file to avoid stale records
-            from sqlalchemy import delete as _delete
-            await db.execute(
-                _delete(MediaAsset).where(
-                    MediaAsset.cad_file_id == uuid.UUID(cad_file_id),
-                    MediaAsset.asset_type == MediaAssetType.gltf_geometry,
-                )
+    _sync_url = app_settings.database_url.replace("+asyncpg", "")
+    _eng2 = _ce(_sync_url)
+    with _Session(_eng2) as _sess:
+        _sess.execute(
+            _del(MediaAsset).where(
+                MediaAsset.cad_file_id == _uuid.UUID(cad_file_id),
+                MediaAsset.asset_type == MediaAssetType.gltf_geometry,
             )
-            _key = str(output_path)
-            _prefix = str(_cfg.upload_dir).rstrip("/") + "/"
-            if _key.startswith(_prefix):
-                _key = _key[len(_prefix):]
-            asset = MediaAsset(
-                cad_file_id=uuid.UUID(cad_file_id),
-                asset_type=MediaAssetType.gltf_geometry,
-                storage_key=_key,
-                mime_type="model/gltf-binary",
-                file_size_bytes=output_path.stat().st_size if output_path.exists() else None,
-            )
-            db.add(asset)
-            await db.commit()
-            return str(asset.id)
+        )
+        _key = str(output_path)
+        _prefix = str(app_settings.upload_dir).rstrip("/") + "/"
+        if _key.startswith(_prefix):
+            _key = _key[len(_prefix):]
+        asset = MediaAsset(
+            cad_file_id=_uuid.UUID(cad_file_id),
+            asset_type=MediaAssetType.gltf_geometry,
+            storage_key=_key,
+            mime_type="model/gltf-binary",
+            file_size_bytes=output_path.stat().st_size if output_path.exists() else None,
+        )
+        _sess.add(asset)
+        _sess.commit()
+        asset_id = str(asset.id)
+    _eng2.dispose()
 
-    asset_id = asyncio.run(_store())
     logger.info("generate_gltf_geometry_task: MediaAsset %s created for cad %s", asset_id, cad_file_id)
     return {"glb_path": str(output_path), "asset_id": asset_id}
 

frontend/src/components/cad/InlineCadViewer.tsx

@@ -1,16 +1,81 @@
-import { Suspense, useEffect, useState } from 'react'
+import { Suspense, useEffect, useRef, useState } from 'react'
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
 import { Canvas } from '@react-three/fiber'
-import { OrbitControls, useGLTF } from '@react-three/drei'
-import { Loader2, Box, RefreshCw } from 'lucide-react'
+import { OrbitControls, useGLTF, Environment } from '@react-three/drei'
+import * as THREE from 'three'
+import { mergeVertices } from 'three/examples/jsm/utils/BufferGeometryUtils.js'
+import { Loader2, Box, RefreshCw, Grid3X3, Layers, Sun } from 'lucide-react'
 import { toast } from 'sonner'
 import { getMediaAssets } from '../../api/media'
 import { generateGltfGeometry } from '../../api/cad'
 import { useAuthStore } from '../../store/auth'
 
-function GlbModel({ url }: { url: string }) {
+type ViewMode = 'solid' | 'wireframe'
+type LightPreset = 'studio' | 'warehouse' | 'sunset' | 'park' | 'city'
+
+const LIGHT_PRESETS: { id: LightPreset; label: string }[] = [
+  { id: 'studio', label: 'Studio' },
+  { id: 'warehouse', label: 'Warehouse' },
+  { id: 'sunset', label: 'Sunset' },
+  { id: 'park', label: 'Park' },
+  { id: 'city', label: 'City' },
+]
+
+function GlbModel({ url, wireframe }: { url: string; wireframe: boolean }) {
   const { scene } = useGLTF(url)
-  return <primitive object={scene} />
+  const cloned = useRef<THREE.Group | null>(null)
+
+  if (!cloned.current) {
+    cloned.current = scene.clone(true)
+    cloned.current.traverse((obj) => {
+      if (obj instanceof THREE.Mesh && obj.geometry) {
+        let geo = obj.geometry.clone()
+        if (!geo.index) {
+          // Non-indexed geometry (STL→GLB via trimesh): each triangle has unique vertices,
+          // so computeVertexNormals() would give per-face normals (flat shading).
+          // mergeVertices() creates an indexed geometry with shared vertices first,
+          // so the subsequent normal computation averages across adjacent faces → smooth.
+          geo = mergeVertices(geo)
+        }
+        // For indexed geometry (Blender GLB): normals are already baked smooth by Blender.
+        // Recomputing here still works correctly because shared vertices average properly.
+        geo.computeVertexNormals()
+        obj.geometry = geo
+      }
+    })
+  }
+
+  useEffect(() => {
+    cloned.current?.traverse((obj) => {
+      if (obj instanceof THREE.Mesh && obj.material) {
+        const mats = Array.isArray(obj.material) ? obj.material : [obj.material]
+        mats.forEach((m) => {
+          ;(m as THREE.MeshStandardMaterial).wireframe = wireframe
+          m.needsUpdate = true
+        })
+      }
+    })
+  }, [wireframe])
+
+  return <primitive object={cloned.current} />
+}
+
+const HEIGHT = 420
+
+function ToolbarBtn({
+  active, onClick, children, title,
+}: { active: boolean; onClick: () => void; children: React.ReactNode; title?: string }) {
+  return (
+    <button
+      title={title}
+      onClick={onClick}
+      className={`px-2 py-1 text-[11px] flex items-center gap-1 transition-colors ${
+        active ? 'bg-white/20 text-white' : 'text-white/50 hover:text-white/80 hover:bg-white/10'
+      }`}
+    >
+      {children}
+    </button>
+  )
 }
 
 export default function InlineCadViewer({
@@ -25,6 +90,8 @@ export default function InlineCadViewer({
   const [glbBlobUrl, setGlbBlobUrl] = useState<string | null>(null)
   const [loadingGlb, setLoadingGlb] = useState(false)
   const [generating, setGenerating] = useState(false)
+  const [viewMode, setViewMode] = useState<ViewMode>('solid')
+  const [lightPreset, setLightPreset] = useState<LightPreset>('studio')
 
   const { data: gltfAssets } = useQuery({
     queryKey: ['media-assets', cadFileId, 'gltf_geometry'],
@@ -33,7 +100,6 @@ export default function InlineCadViewer({
     refetchInterval: generating ? 4_000 : false,
   })
 
-  // Stop polling once asset appears
   useEffect(() => {
     if (generating && gltfAssets && gltfAssets.length > 0) setGenerating(false)
   }, [generating, gltfAssets])
@@ -41,7 +107,6 @@ export default function InlineCadViewer({
   const latestAsset = gltfAssets?.[0]
   const downloadUrl = latestAsset?.download_url
 
-  // Fetch GLB with auth when download URL is available
   useEffect(() => {
     if (!downloadUrl || !token) return
     setLoadingGlb(true)
@@ -69,31 +134,55 @@ export default function InlineCadViewer({
     onError: () => toast.error('Failed to queue GLB generation'),
   })
 
-  // Show GLB viewer
   if (glbBlobUrl) {
     return (
-      <div
-        className="w-full rounded-lg overflow-hidden border border-border-default bg-gray-950"
-        style={{ height: 280 }}
-      >
+      <div className="w-full rounded-lg overflow-hidden border border-border-default bg-gray-950 relative" style={{ height: HEIGHT }}>
         <Canvas camera={{ position: [0, 0, 2], fov: 45 }}>
-          <ambientLight intensity={1.2} />
-          <directionalLight position={[5, 5, 5]} intensity={1} />
           <Suspense fallback={null}>
-            <GlbModel url={glbBlobUrl} />
+            <Environment preset={lightPreset} background={false} />
+            <GlbModel url={glbBlobUrl} wireframe={viewMode === 'wireframe'} />
           </Suspense>
           <OrbitControls makeDefault />
         </Canvas>
+
+        {/* Toolbar */}
+        <div className="absolute top-2 right-2 flex flex-col gap-1 items-end">
+          {/* View mode */}
+          <div className="flex rounded-md overflow-hidden border border-white/10 bg-black/50 backdrop-blur-sm">
+            <ToolbarBtn active={viewMode === 'solid'} onClick={() => setViewMode('solid')} title="Solid">
+              <Layers size={12} /> Solid
+            </ToolbarBtn>
+            <div className="w-px bg-white/10" />
+            <ToolbarBtn active={viewMode === 'wireframe'} onClick={() => setViewMode('wireframe')} title="Wireframe">
+              <Grid3X3 size={12} /> Wire
+            </ToolbarBtn>
+          </div>
+
+          {/* Lighting presets */}
+          <div className="flex rounded-md overflow-hidden border border-white/10 bg-black/50 backdrop-blur-sm">
+            <span className="px-2 py-1 text-[11px] text-white/30 flex items-center">
+              <Sun size={11} />
+            </span>
+            <div className="w-px bg-white/10" />
+            {LIGHT_PRESETS.map((p, i) => (
+              <div key={p.id} className="flex">
+                {i > 0 && <div className="w-px bg-white/10" />}
+                <ToolbarBtn active={lightPreset === p.id} onClick={() => setLightPreset(p.id)} title={p.label}>
+                  {p.label}
+                </ToolbarBtn>
+              </div>
+            ))}
+          </div>
+        </div>
       </div>
     )
   }
 
-  // Loading GLB
   if (loadingGlb) {
     return (
       <div
         className="w-full rounded-lg border border-border-default bg-surface-muted flex items-center justify-center"
-        style={{ height: 280 }}
+        style={{ height: HEIGHT }}
       >
         <div className="flex flex-col items-center gap-2 text-content-muted">
           <Loader2 size={28} className="animate-spin" />
@@ -103,14 +192,13 @@ export default function InlineCadViewer({
     )
   }
 
-  // No GLB yet — show thumbnail + generate button
   return (
     <div
       className="w-full rounded-lg border border-border-default bg-surface-muted flex flex-col items-center justify-center gap-3"
-      style={{ height: 280 }}
+      style={{ height: HEIGHT }}
     >
       {thumbnailUrl ? (
-        <img src={thumbnailUrl} alt="CAD thumbnail" className="max-h-40 object-contain" />
+        <img src={thumbnailUrl} alt="CAD thumbnail" className="max-h-52 object-contain" />
       ) : (
         <Box size={48} className="text-content-muted" />
       )}