refactor: replace STL intermediary with OCC-native STEP→GLB pipeline

- export_step_to_gltf.py: STEP→GLB via RWGltf_CafWriter + BRepBuilderAPI_Transform
  (mm→m pre-scaling, XCAFDoc_ShapeTool.GetComponents_s static method)
- Blender scripts (blender_render.py, still_render.py, turntable_render.py,
  export_gltf.py, export_blend.py): import GLB instead of STL, remove _scale_mm_to_m
- step_tasks.py: add generate_gltf_production_task, remove generate_stl_cache,
  replace _bbox_from_stl with _bbox_from_glb (trimesh), auto-queue geometry GLB
  after thumbnail render
- render_blender.py: replace _stl_from_cache_or_convert with _glb_from_step,
  remove convert_step_to_stl and export_per_part_stls
- domains/rendering/tasks.py: update render_turntable_task, export_gltf/blend tasks
  to use GLB instead of STL
- cad.py: remove STL download/generate endpoints, add generate-gltf-production
- admin.py: generate-missing-stls → generate-missing-geometry-glbs
- Frontend: replace STL cache UI with GLB generate buttons, remove stl_cached field

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

LEARNINGS.md

@@ -27,6 +27,37 @@
 **Lösung**: `_normalize_key()` Helper: strippt `UPLOAD_DIR`-Prefix. In `download_asset` Legacy-Remapping für alte Pfade als Fallback behalten. Neue Assets immer relativ speichern.
 **Für künftige Projekte**: `storage_key` immer relativ zu `UPLOAD_DIR` → `candidate = Path(settings.upload_dir) / key`. Absolute Pfade nie in die DB schreiben.
 
+### 2026-03-07 | OCP | `RWMesh_CoordinateSystemConverter` nicht als Python-Binding verfügbar (OCP 7.8.1.1)
+**Problem**: `writer.ChangeCoordinateSystemConverter()` wirft `TypeError: Unregistered type : RWMesh_CoordinateSystemConverter` — der C++-Typ ist nicht in OCP-Python-Bindings registriert.
+**Lösung**: Shapes vor dem Export mit `BRepBuilderAPI_Transform` um Faktor 0.001 skalieren (mm→m). Dann `RWGltf_CafWriter` direkt ohne Koordinatensystem-Konverter aufrufen.
+```python
+trsf = gp_Trsf()
+trsf.SetScaleFactor(0.001)
+for i in range(1, free_labels.Length() + 1):
+    label = free_labels.Value(i)
+    scaled = BRepBuilderAPI_Transform(shape_tool.GetShape_s(label), trsf, True).Shape()
+    shape_tool.SetShape(label, scaled)
+```
+**Für künftige Projekte**: Immer OCP-Methoden-Verfügbarkeit mit `hasattr()` oder `dir()` testen bevor man sie aufruft.
+
+### 2026-03-07 | OCP | `XCAFDoc_ShapeTool.GetComponents` → `GetComponents_s` (static method suffix)
+**Problem**: `shape_tool.GetComponents(label, seq)` → `AttributeError: 'XCAFDoc_ShapeTool' has no attribute 'GetComponents'`
+**Lösung**: In OCP sind alle XCAF static-Methoden mit `_s`-Suffix: `XCAFDoc_ShapeTool.GetComponents_s(label, seq)`. Gilt für alle `XCAFDoc_*`-Klassen.
+
+### 2026-03-07 | Pipeline | OCC-native STEP→GLB ersetzt STL-Intermediary komplett
+**Problem**: Pipeline nutzte STL als Zwischenformat (STEP→STL via cadquery, STL→Blender). STL verliert Materialnamen, Farben, OCC-Topologie. Zwei parallele Konvertierungen (cadquery STL + Blender Import) = doppelter Aufwand. STL-Cache auf Disk = Dateiflut.
+**Lösung**: `export_step_to_gltf.py` nutzt OCC `RWGltf_CafWriter` direkt: STEP→GLB in einem Schritt. Koordinatensystem-Konvertierung (Z-up→Y-up) + mm→m Skalierung übernimmt `conv.SetInputLengthUnit(1e-3)`. Blender importiert GLB nativ via `bpy.ops.import_scene.gltf()` — kein `_scale_mm_to_m` mehr nötig.
+**OCC-API-Gotcha**: Projekt nutzt `OCP` (cadquery's pythonocc-Bindings), NICHT `OCC.Core`. Statische Methoden haben `_s`-Suffix: `XCAFApp_Application.GetApplication_s()`, `XCAFDoc_DocumentTool.ShapeTool_s()`.
+**Für künftige Projekte**: `RWGltf_CafWriter` + `STEPCAFControl_Reader` sind die kanonische STEP→GLB Pipeline. `BRepMesh_IncrementalMesh` tesselliert vor dem Export. `XCAFDoc_ColorTool.SetColor(label, color, XCAFDoc_ColorSurf)` überträgt Farben in GLB-Materialien.
+
+### 2026-03-07 | Celery | generate_gltf_geometry_task als Subprocess — kein bpy-Import-Konflikt
+**Problem**: OCP und bpy können nicht im selben Python-Prozess koexistieren — OCP lädt native C++-Bibliotheken die mit Blenders internen Versionen kollidieren. Der render-worker-Container hat BEIDE (cadquery + Blender).
+**Lösung**: `export_step_to_gltf.py` via `sys.executable` subprocess aus Celery-Task heraus starten. So läuft OCC in isoliertem Prozess, kein Import-Pollution. Pattern: `subprocess.run([sys.executable, script, "--arg", val], timeout=120)`.
+
+### 2026-03-07 | Bbox | GLB statt STL für Bounding-Box Extraktion
+**Problem**: `_bbox_from_stl()` nutzte numpy binary parsing des STL-Headers (schnell, aber STL existiert nicht mehr nach Pipeline-Umbau).
+**Lösung**: `_bbox_from_glb()` mit trimesh: `scene = trimesh.load(glb_path, force="scene"); bounds = scene.bounds`. GLB ist in Metern → `* 1000` für mm. Fallback auf `_bbox_from_step_cadquery()` bleibt erhalten.
+
 ### 2026-03-07 | Workflow | Turntable-Workflow brauchte step_path zur Laufzeit
 **Problem**: `WorkflowDefinition.config` ist statisch (JSON) — enthält keine produktspezifischen Pfade. `_build_turntable()` erwartet `step_path` + `output_dir` in params → `ValueError` bei Workflow-Dispatch.
 **Lösung**: `dispatch_render_with_workflow()` löst `step_path` + `output_dir` aus dem `OrderLine → Product → CadFile` Graph auf und injiziert sie in params vor `dispatch_workflow()`.

backend/app/api/routers/admin.py

@@ -438,30 +438,36 @@ async def reextract_all_metadata(
     return {"queued": queued, "message": f"Queued {queued} CAD file(s) for metadata re-extraction"}
 
 
-@router.post("/settings/generate-missing-stls", status_code=status.HTTP_202_ACCEPTED)
-async def generate_missing_stls(
+@router.post("/settings/generate-missing-geometry-glbs", status_code=status.HTTP_202_ACCEPTED)
+async def generate_missing_geometry_glbs(
     admin: User = Depends(require_admin),
     db: AsyncSession = Depends(get_db),
 ):
-    """Queue STL generation for every quality missing from each completed CAD file."""
-    from pathlib import Path as _Path
+    """Queue geometry GLB generation for every completed CAD file that has no gltf_geometry MediaAsset."""
+    import uuid as _uuid
+    from app.domains.media.models import MediaAsset, MediaAssetType
+
     result = await db.execute(
         select(CadFile).where(CadFile.processing_status == ProcessingStatus.completed)
     )
     cad_files = result.scalars().all()
 
-    from app.tasks.step_tasks import generate_stl_cache
+    # Bulk-fetch existing gltf_geometry assets
+    existing_result = await db.execute(
+        select(MediaAsset.cad_file_id).where(MediaAsset.asset_type == MediaAssetType.gltf_geometry)
+    )
+    existing_ids = {row[0] for row in existing_result.all()}
+
+    from app.tasks.step_tasks import generate_gltf_geometry_task
     queued = 0
     for cad_file in cad_files:
         if not cad_file.stored_path:
             continue
-        step = _Path(cad_file.stored_path)
-        for quality in ("low", "high"):
-            if not (step.parent / f"{step.stem}_{quality}.stl").exists():
-                generate_stl_cache.delay(str(cad_file.id), quality)
+        if cad_file.id not in existing_ids:
+            generate_gltf_geometry_task.delay(str(cad_file.id))
             queued += 1
 
-    return {"queued": queued, "message": f"Queued {queued} missing STL generation task(s)"}
+    return {"queued": queued, "message": f"Queued {queued} missing geometry GLB task(s)"}
 
 
 @router.post("/settings/seed-workflows", status_code=status.HTTP_200_OK)

backend/app/api/routers/cad.py

@@ -262,78 +262,16 @@ async def get_objects(
     }
 
 
-@router.get("/{id}/stl/{quality}")
-async def download_stl(
-    id: uuid.UUID,
-    quality: str,
-    user: User = Depends(get_current_user),
-    db: AsyncSession = Depends(get_db),
-):
-    """Download the cached STL for a CAD file with a human-readable filename.
-
-    The STL is cached next to the STEP file on first render.
-    quality must be 'low' or 'high'.
-    """
-    if quality not in ("low", "high"):
-        raise HTTPException(400, detail="quality must be 'low' or 'high'")
-
-    cad = await _get_cad_file(id, db)
-
-    if not cad.stored_path:
-        raise HTTPException(404, detail="STEP file not uploaded for this CAD file")
-
-    step_path = Path(cad.stored_path)
-    stl_path = step_path.parent / f"{step_path.stem}_{quality}.stl"
-
-    if not stl_path.exists():
-        raise HTTPException(
-            404,
-            detail=f"STL cache not found for quality '{quality}'. Trigger a render first to generate it.",
-        )
-
-    original_stem = Path(cad.original_name or "model").stem
-    filename = f"{original_stem}_{quality}.stl"
-
-    return FileResponse(
-        path=str(stl_path),
-        media_type="application/octet-stream",
-        filename=filename,
-    )
-
-
-@router.post("/{id}/generate-stl/{quality}", status_code=status.HTTP_202_ACCEPTED)
-async def generate_stl(
-    id: uuid.UUID,
-    quality: str,
-    user: User = Depends(get_current_user),
-    db: AsyncSession = Depends(get_db),
-):
-    """Queue STL generation for the given quality without triggering a full render."""
-    if user.role.value not in ("admin", "project_manager"):
-        raise HTTPException(status_code=403, detail="Insufficient permissions")
-    if quality not in ("low", "high"):
-        raise HTTPException(status_code=400, detail="quality must be 'low' or 'high'")
-
-    cad = await _get_cad_file(id, db)
-
-    if not cad.stored_path:
-        raise HTTPException(status_code=404, detail="STEP file not uploaded for this CAD file")
-
-    from app.tasks.step_tasks import generate_stl_cache
-    task = generate_stl_cache.delay(str(id), quality)
-    return {"status": "queued", "task_id": task.id, "quality": quality}
-
-
 @router.post("/{id}/generate-gltf-geometry", status_code=status.HTTP_202_ACCEPTED)
 async def generate_gltf_geometry(
     id: uuid.UUID,
     user: User = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
-    """Queue GLB geometry export from the existing STL cache (trimesh, no Blender).
+    """Queue GLB geometry export directly from STEP via OCC (no STL required).
 
     Stores the result as a MediaAsset with asset_type='gltf_geometry'.
-    The STL low-quality cache must already exist (run a thumbnail render first).
+    Uses export_step_to_gltf.py (OCP/pythonocc) — no Blender needed.
     """
     if user.role.value not in ("admin", "project_manager"):
         raise HTTPException(status_code=403, detail="Insufficient permissions")
@@ -342,20 +280,34 @@ async def generate_gltf_geometry(
     if not cad.stored_path:
         raise HTTPException(status_code=404, detail="STEP file not uploaded for this CAD file")
 
-    step_path = Path(cad.stored_path)
-    stl_path = step_path.parent / f"{step_path.stem}_low.stl"
-    if not stl_path.exists():
-        raise HTTPException(
-            status_code=404,
-            detail="STL low-quality cache not found. Trigger a render first to generate it.",
-        )
-
-    # Queue as a thumbnail_rendering task (trimesh available in render-worker)
     from app.tasks.step_tasks import generate_gltf_geometry_task
     task = generate_gltf_geometry_task.delay(str(id))
     return {"status": "queued", "task_id": task.id, "cad_file_id": str(id)}
 
 
+@router.post("/{id}/generate-gltf-production", status_code=status.HTTP_202_ACCEPTED)
+async def generate_gltf_production(
+    id: uuid.UUID,
+    user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Queue production GLB export (Blender + PBR materials) from a geometry GLB.
+
+    Requires a gltf_geometry MediaAsset to already exist (run generate-gltf-geometry first).
+    Stores result as a MediaAsset with asset_type='gltf_production'.
+    """
+    if user.role.value not in ("admin", "project_manager"):
+        raise HTTPException(status_code=403, detail="Insufficient permissions")
+
+    cad = await _get_cad_file(id, db)
+    if not cad.stored_path:
+        raise HTTPException(status_code=404, detail="STEP file not uploaded for this CAD file")
+
+    from app.tasks.step_tasks import generate_gltf_production_task
+    task = generate_gltf_production_task.delay(str(id))
+    return {"status": "queued", "task_id": task.id, "cad_file_id": str(id)}
+
+
 @router.post(
     "/{id}/regenerate-thumbnail",
     status_code=status.HTTP_202_ACCEPTED,
@@ -396,146 +348,3 @@ async def regenerate_thumbnail(
     }
 
 
-@router.get("/{id}/export-gltf-colored")
-async def export_gltf_colored(
-    id: uuid.UUID,
-    user: User = Depends(get_current_user),
-    db: AsyncSession = Depends(get_db),
-):
-    """Export a GLB with PBR colors from part_colors (material alias mapping).
-
-    Loads per-part STLs from the low-quality parts cache directory and applies
-    PBR materials based on the product's cad_part_materials color assignments.
-    Falls back to the combined STL with a single grey material.
-    """
-    from fastapi.responses import Response
-    from sqlalchemy import text, select
-    import trimesh
-    import io
-
-    if user.role.value not in ("admin", "project_manager"):
-        raise HTTPException(status_code=403, detail="Insufficient permissions")
-
-    # Bypass RLS for cad_files + products
-    await db.execute(text("SET LOCAL app.current_tenant_id = 'bypass'"))
-    cad = await _get_cad_file(id, db)
-
-    if not cad.stored_path:
-        raise HTTPException(404, detail="STEP file not uploaded")
-
-    step_path = Path(cad.stored_path)
-    stl_path = step_path.parent / f"{step_path.stem}_low.stl"
-    parts_dir = step_path.parent / f"{step_path.stem}_low_parts"
-
-    if not stl_path.exists():
-        raise HTTPException(404, detail="STL cache not found. Trigger a render first.")
-
-    # Load settings
-    from app.models.system_setting import SystemSetting
-    settings_result = await db.execute(
-        select(SystemSetting.key, SystemSetting.value).where(
-            SystemSetting.key.in_([
-                "gltf_scale_factor", "gltf_smooth_normals",
-                "gltf_pbr_roughness", "gltf_pbr_metallic",
-            ])
-        )
-    )
-    raw_settings = {k: v for k, v in settings_result.all()}
-    scale = float(raw_settings.get("gltf_scale_factor", "0.001"))
-    smooth = raw_settings.get("gltf_smooth_normals", "true") == "true"
-    roughness = float(raw_settings.get("gltf_pbr_roughness", "0.4"))
-    metallic = float(raw_settings.get("gltf_pbr_metallic", "0.6"))
-
-    # Load part colors from product
-    from app.domains.products.models import Product
-    part_colors: dict[str, str] = {}
-    if cad.id:
-        prod_result = await db.execute(
-            select(Product).where(Product.cad_file_id == cad.id).limit(1)
-        )
-        product = prod_result.scalar_one_or_none()
-        if product and product.cad_part_materials:
-            for entry in product.cad_part_materials:
-                part_name = entry.get("part_name") or entry.get("name", "")
-                hex_color = entry.get("hex_color") or entry.get("color", "")
-                if part_name and hex_color:
-                    part_colors[part_name] = hex_color
-
-    def _hex_to_rgba(h: str) -> list:
-        h = h.lstrip("#")
-        if len(h) < 6:
-            return [0.7, 0.7, 0.7, 1.0]
-        try:
-            return [int(h[i:i+2], 16) / 255.0 for i in (0, 2, 4)] + [1.0]
-        except Exception:
-            return [0.7, 0.7, 0.7, 1.0]
-
-    def _make_material(hex_color: str | None = None):
-        rgba = _hex_to_rgba(hex_color) if hex_color else [0.7, 0.7, 0.7, 1.0]
-        return trimesh.visual.material.PBRMaterial(
-            baseColorFactor=rgba,
-            roughnessFactor=roughness,
-            metallicFactor=metallic,
-        )
-
-    def _apply_mesh(mesh, color=None):
-        mesh.apply_scale(scale)
-        if smooth:
-            try:
-                trimesh.smoothing.filter_laplacian(mesh, lamb=0.5, iterations=5)
-            except Exception:
-                pass
-        mesh.visual = trimesh.visual.TextureVisuals(material=_make_material(color))
-        return mesh
-
-    # Try per-part STLs first
-    scene = trimesh.Scene()
-    used_parts = False
-
-    if parts_dir.exists() and part_colors:
-        for part_name, hex_color in part_colors.items():
-            # Sanitize part name for filesystem
-            safe_name = part_name.replace("/", "_").replace("\\", "_")
-            part_stl = parts_dir / f"{safe_name}.stl"
-            if not part_stl.exists():
-                # Try lowercase / partial match
-                candidates = list(parts_dir.glob(f"{safe_name}*.stl"))
-                if not candidates:
-                    candidates = list(parts_dir.glob("*.stl"))
-                    candidates = [c for c in candidates if safe_name.lower() in c.stem.lower()]
-                if candidates:
-                    part_stl = candidates[0]
-                else:
-                    continue
-            try:
-                m = trimesh.load(str(part_stl), force="mesh")
-                _apply_mesh(m, hex_color)
-                scene.add_geometry(m, geom_name=part_name)
-                used_parts = True
-            except Exception:
-                pass
-
-    if not used_parts:
-        # Fallback: combined STL, single color
-        combined = trimesh.load(str(stl_path))
-        if hasattr(combined, 'geometry'):
-            for name, m in combined.geometry.items():
-                _apply_mesh(m, next(iter(part_colors.values()), None))
-                scene.add_geometry(m, geom_name=name)
-        else:
-            _apply_mesh(combined, next(iter(part_colors.values()), None))
-            scene.add_geometry(combined)
-
-    # Export to bytes
-    buf = io.BytesIO()
-    scene.export(buf, file_type="glb")
-    glb_bytes = buf.getvalue()
-
-    original_stem = Path(cad.original_name or "model").stem
-    filename = f"{original_stem}_colored.glb"
-
-    return Response(
-        content=glb_bytes,
-        media_type="model/gltf-binary",
-        headers={"Content-Disposition": f"attachment; filename={filename}"},
-    )

backend/app/api/routers/products.py

@@ -77,20 +77,9 @@ def _product_out(product: Product, priority: list[str] | None = None) -> Product
     out.cad_parsed_objects = product.cad_parsed_objects
     out.cad_mesh_attributes = product.cad_file.mesh_attributes if product.cad_file else None
     out.render_image_url = _best_render_url(product, priority or ["latest_render", "cad_thumbnail"])
-    out.stl_cached = _stl_cached_qualities(product)
     return out
 
 
-def _stl_cached_qualities(product: Product) -> list[str]:
-    """Return list of STL qualities that are cached on disk for this product."""
-    from pathlib import Path as _Path
-    cad = product.cad_file
-    if not cad or not cad.stored_path:
-        return []
-    step = _Path(cad.stored_path)
-    return [q for q in ("low", "high") if (step.parent / f"{step.stem}_{q}.stl").exists()]
-
-
 async def _load_thumbnail_priority(db: AsyncSession) -> list[str]:
     """Read product_thumbnail_priority from system_settings.
 

backend/app/domains/products/schemas.py

@@ -59,7 +59,6 @@ class ProductOut(BaseModel):
     thumbnail_url: str | None = None
     render_image_url: str | None = None
     processing_status: str | None = None
-    stl_cached: list[str] = []
     cad_parsed_objects: list[str] | None = None
     cad_mesh_attributes: dict | None = None
     arbeitspaket: str | None = None

backend/app/domains/rendering/tasks.py

@@ -193,9 +193,8 @@ def render_turntable_task(
     import os
     import shutil
     import subprocess
-    from app.services.render_blender import (
-        find_blender, convert_step_to_stl, export_per_part_stls
-    )
+    import sys
+    from app.services.render_blender import find_blender
 
     blender_bin = find_blender()
     if not blender_bin:
@@ -208,27 +207,25 @@ def render_turntable_task(
     scripts_dir = Path(os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
     turntable_script = scripts_dir / "turntable_render.py"
 
-    # STL conversion — try MinIO cache first, then convert locally
-    stl_path = step.parent / f"{step.stem}_{stl_quality}.stl"
-    if not stl_path.exists() or stl_path.stat().st_size == 0:
-        try:
-            from app.domains.products.cache_service import compute_step_hash, check_stl_cache
-            step_hash = compute_step_hash(str(step))
-            cached = check_stl_cache(step_hash, stl_quality)
-            if cached:
-                stl_path.write_bytes(cached)
-                logger.info("STL restored from MinIO cache: %s", stl_path.name)
-            else:
-                convert_step_to_stl(step, stl_path, stl_quality)
-        except Exception as exc:
-            logger.warning("MinIO cache check failed (non-fatal): %s — falling back to conversion", exc)
-            convert_step_to_stl(step, stl_path, stl_quality)
-    parts_dir = step.parent / f"{step.stem}_{stl_quality}_parts"
-    if not (parts_dir / "manifest.json").exists():
-        try:
-            export_per_part_stls(step, parts_dir, stl_quality)
-        except Exception as exc:
-            logger.warning("per-part export non-fatal: %s", exc)
+    # GLB generation via OCC (replaces STL intermediary)
+    linear_deflection = 0.3 if stl_quality == "low" else 0.05
+    angular_deflection = 0.3 if stl_quality == "low" else 0.1
+    glb_path = step.parent / f"{step.stem}_{stl_quality}.glb"
+    if not glb_path.exists() or glb_path.stat().st_size == 0:
+        occ_script = scripts_dir / "export_step_to_gltf.py"
+        occ_cmd = [
+            sys.executable, str(occ_script),
+            "--step_path", str(step),
+            "--output_path", str(glb_path),
+            "--linear_deflection", str(linear_deflection),
+            "--angular_deflection", str(angular_deflection),
+        ]
+        occ_result = subprocess.run(occ_cmd, capture_output=True, text=True, timeout=120)
+        if occ_result.returncode != 0:
+            raise RuntimeError(
+                f"export_step_to_gltf.py failed:\n{occ_result.stderr[-500:]}"
+            )
+        logger.info("render_turntable_task: GLB generated: %s", glb_path.name)
 
     # Build turntable render arguments
     frames_dir = out_dir / "frames"
@@ -238,7 +235,7 @@ def render_turntable_task(
         blender_bin, "--background",
         "--python", str(turntable_script),
         "--",
-        str(stl_path),
+        str(glb_path),
         str(frames_dir),
         output_name,
         str(width), str(height),
@@ -463,93 +460,40 @@ def render_order_line_still_task(self, order_line_id: str, **params) -> dict:
     max_retries=1,
 )
 def export_gltf_for_order_line_task(self, order_line_id: str) -> dict:
-    """Export a GLB from the STL cache via Blender subprocess (with trimesh fallback).
+    """Export a geometry GLB directly from STEP via OCC (no STL intermediary).
 
-    Publishes a MediaAsset with asset_type='gltf_geometry' (no asset lib) or
-    'gltf_production' (when an asset library is applied).
-    Requires the STL low-quality cache to exist.
+    Publishes a MediaAsset with asset_type='gltf_geometry'.
     """
-    import json
     import os
     import subprocess
+    import sys
 
     step_path_str, cad_file_id = _resolve_step_path_for_order_line(order_line_id)
     if not step_path_str:
         raise RuntimeError(f"Cannot resolve STEP path for order_line {order_line_id}")
 
     step = Path(step_path_str)
-    stl_path = step.parent / f"{step.stem}_low.stl"
-    if not stl_path.exists():
-        raise RuntimeError(
-            f"STL cache not found: {stl_path}. Run thumbnail generation first."
-        )
-
     output_path = step.parent / f"{step.stem}_geometry.glb"
     scripts_dir = Path(os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
-    export_script = scripts_dir / "export_gltf.py"
+    occ_script = scripts_dir / "export_step_to_gltf.py"
 
-    from app.services.render_blender import find_blender, is_blender_available
+    if not occ_script.exists():
+        raise RuntimeError(f"export_step_to_gltf.py not found at {occ_script}")
 
-    asset_type = "gltf_geometry"
-
-    # Load sharp edge hints from mesh_attributes for UV seam marking
-    sharp_edges_json = "[]"
-    if cad_file_id:
     try:
-            import asyncio as _asyncio
-
-            async def _load_mesh_attrs() -> list:
-                from app.database import AsyncSessionLocal
-                from app.models.cad_file import CadFile as _CF
-                from sqlalchemy import select as _sel
-                async with AsyncSessionLocal() as _db:
-                    _res = await _db.execute(_sel(_CF).where(_CF.id == cad_file_id))
-                    _cad = _res.scalar_one_or_none()
-                    if _cad and _cad.mesh_attributes:
-                        return _cad.mesh_attributes.get("sharp_edge_midpoints") or []
-                    return []
-
-            _midpoints = _asyncio.get_event_loop().run_until_complete(_load_mesh_attrs())
-            if _midpoints:
-                sharp_edges_json = json.dumps(_midpoints)
-        except Exception as _exc:
-            logger.warning("Could not load sharp_edge_midpoints for %s: %s", cad_file_id, _exc)
-
-    if is_blender_available() and export_script.exists():
-        blender_bin = find_blender()
         cmd = [
-            blender_bin, "--background",
-            "--python", str(export_script),
-            "--",
-            "--stl_path", str(stl_path),
+            sys.executable, str(occ_script),
+            "--step_path", str(step),
             "--output_path", str(output_path),
-            "--asset_library_blend", "",
-            "--material_map", json.dumps({}),
-            "--sharp_edges_json", sharp_edges_json,
         ]
-        try:
-            result = subprocess.run(cmd, capture_output=True, text=True, timeout=300)
+        result = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
         if result.returncode != 0:
             raise RuntimeError(
-                    f"export_gltf.py exited {result.returncode}:\n{result.stderr[-500:]}"
+                f"export_step_to_gltf.py exited {result.returncode}:\n{result.stderr[-500:]}"
             )
-            publish_asset.delay(order_line_id, asset_type, str(output_path))
-            logger.info("export_gltf_for_order_line_task completed via Blender: %s", output_path.name)
-            return {"glb_path": str(output_path), "method": "blender"}
-        except Exception as exc:
-            logger.warning(
-                "Blender GLB export failed for %s, falling back to trimesh: %s",
-                order_line_id, exc,
-            )
-
-    # Trimesh fallback
-    try:
-        import trimesh
-        mesh = trimesh.load(str(stl_path))
-        mesh.export(str(output_path))
-        publish_asset.delay(order_line_id, asset_type, str(output_path))
-        logger.info("export_gltf_for_order_line_task completed via trimesh: %s", output_path.name)
-        return {"glb_path": str(output_path), "method": "trimesh"}
+        publish_asset.delay(order_line_id, "gltf_geometry", str(output_path))
+        logger.info("export_gltf_for_order_line_task completed via OCC: %s", output_path.name)
+        return {"glb_path": str(output_path), "method": "occ"}
     except Exception as exc:
         logger.error("export_gltf_for_order_line_task failed for %s: %s", order_line_id, exc)
         raise self.retry(exc=exc, countdown=15)
@@ -576,9 +520,20 @@ def export_blend_for_order_line_task(self, order_line_id: str) -> dict:
         raise RuntimeError(f"Cannot resolve STEP path for order_line {order_line_id}")
 
     step = Path(step_path_str)
-    stl_path = step.parent / f"{step.stem}_low.stl"
-    if not stl_path.exists():
-        raise RuntimeError(f"STL cache not found: {stl_path}")
+    # Use geometry GLB as input (generate if missing)
+    glb_path = step.parent / f"{step.stem}_geometry.glb"
+    if not glb_path.exists():
+        import subprocess as _sp
+        import sys as _sys
+        scripts_dir_tmp = Path(os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
+        occ_cmd = [
+            _sys.executable, str(scripts_dir_tmp / "export_step_to_gltf.py"),
+            "--step_path", str(step),
+            "--output_path", str(glb_path),
+        ]
+        occ_res = _sp.run(occ_cmd, capture_output=True, text=True, timeout=120)
+        if occ_res.returncode != 0:
+            raise RuntimeError(f"GLB generation failed:\n{occ_res.stderr[-500:]}")
 
     output_path = step.parent / f"{step.stem}_production.blend"
     scripts_dir = Path(os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
@@ -617,7 +572,7 @@ def export_blend_for_order_line_task(self, order_line_id: str) -> dict:
             blender_bin, "--background",
             "--python", str(export_script),
             "--",
-            "--stl_path", str(stl_path),
+            "--glb_path", str(glb_path),
             "--output_path", str(output_path),
             "--asset_library_blend", asset_lib_path,
             "--material_map", json.dumps(mat_map),
@@ -670,7 +625,7 @@ def apply_asset_library_materials_task(self, order_line_id: str, asset_library_i
             if not product or not product.cad_file_id:
                 return None, None, None
             cad = s.execute(sql_select(CadFile).where(CadFile.id == product.cad_file_id)).scalar_one_or_none()
-            stl_path = str(Path(cad.stored_path).parent / f"{Path(cad.stored_path).stem}_low.stl") if cad else None
+            glb_path = str(Path(cad.stored_path).parent / f"{Path(cad.stored_path).stem}_geometry.glb") if cad else None
 
             # Resolve asset library blend path
             try:
@@ -681,24 +636,24 @@ def apply_asset_library_materials_task(self, order_line_id: str, asset_library_i
                 blend_path = None
 
             mat_map = {m.get("part_name", ""): m.get("material", "") for m in (product.cad_part_materials or [])}
-            return stl_path, blend_path, mat_map
+            return glb_path, blend_path, mat_map
 
     result = _inner()
     if result is None or result[0] is None:
         logger.warning("apply_asset_library_materials_task: could not resolve paths for %s", order_line_id)
         return {"status": "skipped"}
 
-    stl_path, blend_path, mat_map = result
-    if not stl_path or not Path(stl_path).exists():
-        logger.warning("STL not found for %s", order_line_id)
-        return {"status": "skipped", "reason": "stl_not_found"}
+    glb_path, blend_path, mat_map = result
+    if not glb_path or not Path(glb_path).exists():
+        logger.warning("Geometry GLB not found for %s", order_line_id)
+        return {"status": "skipped", "reason": "glb_not_found"}
 
     scripts_dir = Path(os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
     script = scripts_dir / "asset_library.py"
 
     cmd = [
         blender_bin, "--background", "--python", str(script), "--",
-        "--stl_path", stl_path,
+        "--glb_path", glb_path,
         "--asset_library_blend", blend_path or "",
         "--material_map", json.dumps(mat_map),
     ]

backend/app/services/render_blender.py

@@ -17,24 +17,39 @@ logger = logging.getLogger(__name__)
 MIN_BLENDER_VERSION = (5, 0, 1)
 
 
-def _stl_from_cache_or_convert(step_path: Path, stl_path: Path, quality: str) -> None:
-    """Try MinIO cache first, then fall back to local STEP→STL conversion."""
-    # MinIO cache check (non-fatal — cache miss just means we convert normally)
-    try:
-        from app.domains.products.cache_service import compute_step_hash, check_stl_cache
-        step_hash = compute_step_hash(str(step_path))
-        cached_bytes = check_stl_cache(step_hash, quality)
-        if cached_bytes:
-            stl_path.write_bytes(cached_bytes)
-            logger.info("STL restored from MinIO cache: %s (%d KB)", stl_path.name, len(cached_bytes) // 1024)
-            return
-    except Exception as exc:
-        logger.warning("MinIO cache check failed (non-fatal): %s", exc)
+def _glb_from_step(step_path: Path, glb_path: Path, quality: str = "low") -> None:
+    """Convert STEP → GLB via OCC (export_step_to_gltf.py, no Blender needed).
 
-    # Local conversion
-    from app.services.step_processor import convert_step_to_stl
-    logger.info("STL cache miss — converting: %s", step_path.name)
-    convert_step_to_stl(step_path, stl_path, quality)
+    quality: "low" → coarser mesh (~0.3 mm deflection, fast)
+             "high" → finer mesh (~0.05 mm deflection, slower)
+    """
+    import subprocess
+    import sys as _sys
+
+    linear_deflection  = 0.3  if quality == "low" else 0.05
+    angular_deflection = 0.3  if quality == "low" else 0.1
+
+    scripts_dir = Path(os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
+    script_path = scripts_dir / "export_step_to_gltf.py"
+
+    cmd = [
+        _sys.executable, str(script_path),
+        "--step_path", str(step_path),
+        "--output_path", str(glb_path),
+        "--linear_deflection", str(linear_deflection),
+        "--angular_deflection", str(angular_deflection),
+    ]
+    result = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
+    for line in result.stdout.splitlines():
+        logger.info("[occ-gltf] %s", line)
+    for line in result.stderr.splitlines():
+        logger.warning("[occ-gltf stderr] %s", line)
+    if result.returncode != 0 or not glb_path.exists() or glb_path.stat().st_size == 0:
+        raise RuntimeError(
+            f"export_step_to_gltf.py failed (exit {result.returncode}).\n"
+            f"STDERR: {result.stderr[-1000:]}"
+        )
+    logger.info("GLB converted: %s (%d KB)", glb_path.name, glb_path.stat().st_size // 1024)
 
 
 def find_blender() -> str:
@@ -51,127 +66,6 @@ def is_blender_available() -> bool:
     return bool(find_blender())
 
 
-def convert_step_to_stl(step_path: Path, stl_path: Path, quality: str = "low") -> None:
-    """Convert a STEP file to STL using cadquery.
-
-    Raises ImportError if cadquery is not installed (not available in backend
-    container — only in render-worker container).
-    """
-    import cadquery as cq  # only available in render-worker
-
-    if quality == "high":
-        shape = cq.importers.importStep(str(step_path))
-        cq.exporters.export(shape, str(stl_path), tolerance=0.01, angularTolerance=0.02)
-    else:
-        shape = cq.importers.importStep(str(step_path))
-        cq.exporters.export(shape, str(stl_path), tolerance=0.3, angularTolerance=0.3)
-
-    if not stl_path.exists() or stl_path.stat().st_size == 0:
-        raise RuntimeError("cadquery produced empty STL")
-
-
-def export_per_part_stls(step_path: Path, parts_dir: Path, quality: str = "low") -> list:
-    """Export one STL per named STEP leaf shape using OCP XCAF.
-
-    Returns the manifest list (may be empty on failure — non-fatal).
-    """
-    tol = 0.01 if quality == "high" else 0.3
-    angular_tol = 0.05 if quality == "high" else 0.3
-
-    try:
-        from OCP.STEPCAFControl import STEPCAFControl_Reader
-        from OCP.XCAFDoc import XCAFDoc_DocumentTool, XCAFDoc_ShapeTool
-        from OCP.TDataStd import TDataStd_Name
-        from OCP.TDF import TDF_Label as TDF_Label_cls, TDF_LabelSequence
-        from OCP.XCAFApp import XCAFApp_Application
-        from OCP.TDocStd import TDocStd_Document
-        from OCP.TCollection import TCollection_ExtendedString
-        from OCP.IFSelect import IFSelect_RetDone
-        import cadquery as cq
-    except ImportError as e:
-        logger.warning("per-part export skipped (import error): %s", e)
-        return []
-
-    app = XCAFApp_Application.GetApplication_s()
-    doc = TDocStd_Document(TCollection_ExtendedString("XmlOcaf"))
-    app.InitDocument(doc)
-
-    reader = STEPCAFControl_Reader()
-    reader.SetNameMode(True)
-    status = reader.ReadFile(str(step_path))
-    if status != IFSelect_RetDone:
-        logger.warning("XCAF reader failed with status %s", status)
-        return []
-
-    if not reader.Transfer(doc):
-        logger.warning("XCAF transfer failed")
-        return []
-
-    shape_tool = XCAFDoc_DocumentTool.ShapeTool_s(doc.Main())
-    name_id = TDataStd_Name.GetID_s()
-
-    leaves = []
-
-    def _get_label_name(label):
-        name_attr = TDataStd_Name()
-        if label.FindAttribute(name_id, name_attr):
-            return name_attr.Get().ToExtString()
-        return ""
-
-    def _collect_leaves(label):
-        if XCAFDoc_ShapeTool.IsAssembly_s(label):
-            components = TDF_LabelSequence()
-            XCAFDoc_ShapeTool.GetComponents_s(label, components)
-            for i in range(1, components.Length() + 1):
-                comp_label = components.Value(i)
-                if XCAFDoc_ShapeTool.IsReference_s(comp_label):
-                    ref_label = TDF_Label_cls()
-                    XCAFDoc_ShapeTool.GetReferredShape_s(comp_label, ref_label)
-                    comp_name = _get_label_name(comp_label)
-                    ref_name = _get_label_name(ref_label)
-                    name = ref_name or comp_name
-                    if XCAFDoc_ShapeTool.IsAssembly_s(ref_label):
-                        _collect_leaves(ref_label)
-                    elif XCAFDoc_ShapeTool.IsSimpleShape_s(ref_label):
-                        shape = XCAFDoc_ShapeTool.GetShape_s(comp_label)
-                        leaves.append((name or f"unnamed_{len(leaves)}", shape))
-                else:
-                    _collect_leaves(comp_label)
-        elif XCAFDoc_ShapeTool.IsSimpleShape_s(label):
-            name = _get_label_name(label)
-            shape = XCAFDoc_ShapeTool.GetShape_s(label)
-            leaves.append((name or f"unnamed_{len(leaves)}", shape))
-
-    top_labels = TDF_LabelSequence()
-    shape_tool.GetFreeShapes(top_labels)
-    for i in range(1, top_labels.Length() + 1):
-        _collect_leaves(top_labels.Value(i))
-
-    if not leaves:
-        logger.warning("no leaf shapes found via XCAF")
-        return []
-
-    parts_dir.mkdir(parents=True, exist_ok=True)
-    manifest = []
-
-    for idx, (name, shape) in enumerate(leaves):
-        safe_name = name.replace("/", "_").replace("\\", "_").replace(" ", "_")
-        filename = f"{idx:02d}_{safe_name}.stl"
-        filepath = str(parts_dir / filename)
-        try:
-            cq_shape = cq.Shape(shape)
-            cq_shape.exportStl(filepath, tolerance=tol, angularTolerance=angular_tol)
-            manifest.append({"index": idx, "name": name, "file": filename})
-        except Exception as e:
-            logger.warning("failed to export part '%s': %s", name, e)
-
-    manifest_path = parts_dir / "manifest.json"
-    with open(manifest_path, "w") as f:
-        json.dump({"parts": manifest}, f, indent=2)
-
-    return manifest
-
-
 def render_still(
     step_path: Path,
     output_path: Path,
@@ -202,7 +96,7 @@ def render_still(
     denoising_use_gpu: str = "",
     mesh_attributes: dict | None = None,
 ) -> dict:
-    """Convert STEP → STL (cadquery) → PNG (Blender subprocess).
+    """Convert STEP → GLB (OCC) → PNG (Blender subprocess).
 
     Returns a dict with timing, sizes, engine_used, and log_lines.
     Raises RuntimeError on failure.
@@ -215,7 +109,6 @@ def render_still(
 
     script_path = Path(os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts")) / "blender_render.py"
     if not script_path.exists():
-        # Fallback: look next to this file (development mode)
         alt = Path(__file__).parent.parent.parent.parent / "render-worker" / "scripts" / "blender_render.py"
         if alt.exists():
             script_path = alt
@@ -224,24 +117,16 @@ def render_still(
 
     t0 = time.monotonic()
 
-    # 1. STL conversion (cadquery)
-    stl_path = step_path.parent / f"{step_path.stem}_{stl_quality}.stl"
-    parts_dir = step_path.parent / f"{step_path.stem}_{stl_quality}_parts"
+    # 1. GLB conversion (OCC — replaces cadquery STL)
+    glb_path = step_path.parent / f"{step_path.stem}_thumbnail.glb"
 
-    t_stl = time.monotonic()
-    if not stl_path.exists() or stl_path.stat().st_size == 0:
-        _stl_from_cache_or_convert(step_path, stl_path, stl_quality)
+    t_glb = time.monotonic()
+    if not glb_path.exists() or glb_path.stat().st_size == 0:
+        _glb_from_step(step_path, glb_path, quality=stl_quality)
     else:
-        logger.info("STL local hit: %s (%d KB)", stl_path.name, stl_path.stat().st_size // 1024)
-    stl_size_bytes = stl_path.stat().st_size if stl_path.exists() else 0
-
-    if not (parts_dir / "manifest.json").exists():
-        try:
-            export_per_part_stls(step_path, parts_dir, stl_quality)
-        except Exception as exc:
-            logger.warning("per-part STL export failed (non-fatal): %s", exc)
-
-    stl_duration_s = round(time.monotonic() - t_stl, 2)
+        logger.info("GLB local hit: %s (%d KB)", glb_path.name, glb_path.stat().st_size // 1024)
+    glb_size_bytes = glb_path.stat().st_size if glb_path.exists() else 0
+    glb_duration_s = round(time.monotonic() - t_glb, 2)
 
     # 2. Blender render
     output_path.parent.mkdir(parents=True, exist_ok=True)
@@ -263,7 +148,7 @@ def render_still(
             "--background",
             "--python", str(script_path),
             "--",
-            str(stl_path),
+            str(glb_path),
             str(output_path),
             str(width), str(height),
             eng, str(samples), str(smooth_angle),
@@ -332,22 +217,13 @@ def render_still(
 
     render_duration_s = round(time.monotonic() - t_render, 2)
 
-    parts_count = 0
-    manifest_file = parts_dir / "manifest.json"
-    if manifest_file.exists():
-        try:
-            data = json.loads(manifest_file.read_text())
-            parts_count = len(data.get("parts", []))
-        except Exception:
-            pass
-
     return {
         "total_duration_s": round(time.monotonic() - t0, 2),
-        "stl_duration_s": stl_duration_s,
+        "stl_duration_s": glb_duration_s,   # key kept for backward compat with DB render_log
         "render_duration_s": render_duration_s,
-        "stl_size_bytes": stl_size_bytes,
+        "stl_size_bytes": glb_size_bytes,
         "output_size_bytes": output_path.stat().st_size if output_path.exists() else 0,
-        "parts_count": parts_count,
+        "parts_count": 0,
         "engine_used": engine_used,
         "log_lines": log_lines,
     }
@@ -407,24 +283,15 @@ def render_turntable_to_file(
 
     t0 = time.monotonic()
 
-    # 1. STL conversion
-    stl_path = step_path.parent / f"{step_path.stem}_{stl_quality}.stl"
-    parts_dir = step_path.parent / f"{step_path.stem}_{stl_quality}_parts"
+    # 1. GLB conversion (OCC — replaces cadquery STL)
+    glb_path = step_path.parent / f"{step_path.stem}_thumbnail.glb"
 
-    t_stl = time.monotonic()
-    if not stl_path.exists() or stl_path.stat().st_size == 0:
-        _stl_from_cache_or_convert(step_path, stl_path, stl_quality)
+    t_glb = time.monotonic()
+    if not glb_path.exists() or glb_path.stat().st_size == 0:
+        _glb_from_step(step_path, glb_path, quality=stl_quality)
     else:
-        logger.info("STL local hit: %s (%d KB)", stl_path.name, stl_path.stat().st_size // 1024)
-    stl_size_bytes = stl_path.stat().st_size if stl_path.exists() else 0
-
-    if not (parts_dir / "manifest.json").exists():
-        try:
-            export_per_part_stls(step_path, parts_dir, stl_quality)
-        except Exception as exc:
-            logger.warning("per-part STL export failed (non-fatal): %s", exc)
-
-    stl_duration_s = round(time.monotonic() - t_stl, 2)
+        logger.info("GLB local hit: %s (%d KB)", glb_path.name, glb_path.stat().st_size // 1024)
+    glb_duration_s = round(time.monotonic() - t_glb, 2)
 
     # 2. Render frames with Blender
     frames_dir = output_path.parent / f"_frames_{output_path.stem}"
@@ -439,7 +306,7 @@ def render_turntable_to_file(
         "--background",
         "--python", str(script_path),
         "--",
-        str(stl_path),
+        str(glb_path),
         str(frames_dir),
         str(frame_count),
         "360",  # degrees
@@ -554,10 +421,10 @@ def render_turntable_to_file(
 
     return {
         "total_duration_s": round(time.monotonic() - t0, 2),
-        "stl_duration_s": stl_duration_s,
+        "stl_duration_s": glb_duration_s,   # key kept for backward compat with DB render_log
         "render_duration_s": render_duration_s,
         "ffmpeg_duration_s": ffmpeg_duration_s,
-        "stl_size_bytes": stl_size_bytes,
+        "stl_size_bytes": 0,
         "output_size_bytes": output_path.stat().st_size if output_path.exists() else 0,
         "frame_count": len(frame_files),
         "engine_used": engine,

backend/app/tasks/step_tasks.py

@@ -1,6 +1,5 @@
 """Celery tasks for STEP file processing and thumbnail generation."""
 import logging
-import struct
 from pathlib import Path
 from app.tasks.celery_app import celery_app
 from app.core.task_logs import log_task_event
@@ -8,44 +7,37 @@ from app.core.task_logs import log_task_event
 logger = logging.getLogger(__name__)
 
 
-def _bbox_from_stl(stl_path: str) -> dict | None:
-    """Extract bounding box from a cached binary STL file.
+def _bbox_from_glb(glb_path: str) -> dict | None:
+    """Extract bounding box from a GLB file (meters → converted to mm).
 
     Returns {"dimensions_mm": {x,y,z}, "bbox_center_mm": {x,y,z}} or None on failure.
-    Reading vertex extremes from an existing STL is ~10-100× faster than re-parsing STEP.
+    OCC GLB output is in meters; multiply by 1000 to get mm.
     """
     try:
-        import numpy as np
-        p = Path(stl_path)
-        if not p.exists() or p.stat().st_size < 84:
+        import trimesh
+        p = Path(glb_path)
+        if not p.exists():
             return None
-        with p.open("rb") as f:
-            f.seek(80)  # skip 80-byte header
-            n = struct.unpack("<I", f.read(4))[0]
-            if n == 0:
+        scene = trimesh.load(str(p), force="scene")
+        bounds = getattr(scene, "bounds", None)
+        if bounds is None:
             return None
-            raw = f.read(n * 50)  # 50 bytes per triangle
-        # Binary STL per-triangle layout: normal(12B) + v1(12B) + v2(12B) + v3(12B) + attr(2B) = 50B
-        # Extract vertex bytes (columns 12..48 of each 50-byte row)
-        arr = np.frombuffer(raw, dtype=np.uint8).reshape(n, 50)
-        verts = np.frombuffer(arr[:, 12:48].tobytes(), dtype=np.float32).reshape(-1, 3)
-        mins = verts.min(axis=0)
-        maxs = verts.max(axis=0)
+        mins, maxs = bounds
         dims = maxs - mins
         return {
             "dimensions_mm": {
-                "x": round(float(dims[0]), 2),
-                "y": round(float(dims[1]), 2),
-                "z": round(float(dims[2]), 2),
+                "x": round(float(dims[0]) * 1000, 2),
+                "y": round(float(dims[1]) * 1000, 2),
+                "z": round(float(dims[2]) * 1000, 2),
             },
             "bbox_center_mm": {
-                "x": round(float((mins[0] + maxs[0]) / 2), 2),
-                "y": round(float((mins[1] + maxs[1]) / 2), 2),
-                "z": round(float((mins[2] + maxs[2]) / 2), 2),
+                "x": round(float((mins[0] + maxs[0]) / 2) * 1000, 2),
+                "y": round(float((mins[1] + maxs[1]) / 2) * 1000, 2),
+                "z": round(float((mins[2] + maxs[2]) / 2) * 1000, 2),
             },
         }
     except Exception as exc:
-        logger.debug(f"_bbox_from_stl failed for {stl_path}: {exc}")
+        logger.debug(f"_bbox_from_glb failed for {glb_path}: {exc}")
         return None
 
 
@@ -229,9 +221,9 @@ def render_step_thumbnail(self, cad_file_id: str):
         logger.error(f"Thumbnail render failed for {cad_file_id}: {exc}")
         raise self.retry(exc=exc, countdown=30, max_retries=2)
 
-    # Extract bounding box from the STL that was just cached by the renderer.
-    # STL binary parsing is near-instant (numpy min/max) vs re-parsing the STEP file.
-    # Falls back to cadquery STEP re-parse if STL is not found.
+    # Extract bounding box from the thumbnail GLB generated by the renderer.
+    # GLB bbox via trimesh is fast and avoids re-parsing the STEP file.
+    # Falls back to cadquery STEP re-parse if GLB is not found.
     try:
         from sqlalchemy import create_engine
         from sqlalchemy.orm import Session
@@ -247,8 +239,8 @@ def render_step_thumbnail(self, cad_file_id: str):
 
         if _step_path and not (_cad2.mesh_attributes or {}).get("dimensions_mm"):
             _step = Path(_step_path)
-            _stl = _step.parent / f"{_step.stem}_low.stl"
-            bbox_data = _bbox_from_stl(str(_stl)) or _bbox_from_step_cadquery(_step_path)
+            _glb = _step.parent / f"{_step.stem}_thumbnail.glb"
+            bbox_data = _bbox_from_glb(str(_glb)) or _bbox_from_step_cadquery(_step_path)
             if bbox_data:
                 _eng2 = create_engine(_sync_url2)
                 with Session(_eng2) as _sess2:
@@ -295,6 +287,13 @@ def render_step_thumbnail(self, cad_file_id: str):
     except Exception:
         logger.debug("WebSocket publish for CAD complete skipped (non-fatal)")
 
+    # Auto-generate geometry GLB so the 3D viewer is ready without manual trigger
+    try:
+        generate_gltf_geometry_task.delay(cad_file_id)
+        logger.info("render_step_thumbnail: queued generate_gltf_geometry_task for %s", cad_file_id)
+    except Exception:
+        logger.debug("Could not queue generate_gltf_geometry_task (non-fatal)")
+
 
 @celery_app.task(name="app.tasks.step_tasks.reextract_cad_metadata", queue="thumbnail_rendering")
 def reextract_cad_metadata(cad_file_id: str):
@@ -321,8 +320,8 @@ def reextract_cad_metadata(cad_file_id: str):
 
     try:
         p = Path(step_path)
-        stl_path = p.parent / f"{p.stem}_low.stl"
-        patch = _bbox_from_stl(str(stl_path)) or _bbox_from_step_cadquery(step_path)
+        glb_path = p.parent / f"{p.stem}_thumbnail.glb"
+        patch = _bbox_from_glb(str(glb_path)) or _bbox_from_step_cadquery(step_path)
         if patch:
             with Session(eng) as session:
                 cad_file = session.get(CadFile, cad_file_id)
@@ -342,72 +341,22 @@ def reextract_cad_metadata(cad_file_id: str):
         eng.dispose()
 
 
-@celery_app.task(bind=True, name="app.tasks.step_tasks.generate_stl_cache", queue="thumbnail_rendering")
-def generate_stl_cache(self, cad_file_id: str, quality: str):
-    """Generate and cache STL for a CAD file without triggering a full render."""
-    from sqlalchemy import create_engine
-    from sqlalchemy.orm import Session
-    from app.config import settings as app_settings
-    from app.models.cad_file import CadFile
-
-    logger.info(f"Generating {quality}-quality STL for CAD file: {cad_file_id}")
-
-    sync_url = app_settings.database_url.replace("+asyncpg", "")
-    eng = create_engine(sync_url)
-    with Session(eng) as session:
-        cad_file = session.get(CadFile, cad_file_id)
-        if not cad_file or not cad_file.stored_path:
-            logger.error(f"CAD file not found or no stored_path: {cad_file_id}")
-            return
-        step_path = cad_file.stored_path
-    eng.dispose()
-
-    try:
-        from app.services.render_blender import convert_step_to_stl, export_per_part_stls
-        from app.domains.products.cache_service import compute_step_hash, check_stl_cache, store_stl_cache
-        from pathlib import Path as _Path
-        step = _Path(step_path)
-        stl_out = step.parent / f"{step.stem}_{quality}.stl"
-        parts_dir = step.parent / f"{step.stem}_{quality}_parts"
-
-        if not stl_out.exists() or stl_out.stat().st_size == 0:
-            # Check MinIO cache before running cadquery conversion
-            step_hash = compute_step_hash(step_path)
-            cached_bytes = check_stl_cache(step_hash, quality)
-            if cached_bytes:
-                stl_out.write_bytes(cached_bytes)
-                logger.info(f"STL cache hit for {cad_file_id} ({quality}), skipped conversion")
-            else:
-                convert_step_to_stl(step, stl_out, quality)
-                # Store result in MinIO for future workers
-                if stl_out.exists() and stl_out.stat().st_size > 0:
-                    store_stl_cache(step_hash, quality, str(stl_out))
-        if not (parts_dir / "manifest.json").exists():
-            try:
-                export_per_part_stls(step, parts_dir, quality)
-            except Exception as pe:
-                logger.warning(f"Per-part STL export non-fatal: {pe}")
-        logger.info(f"STL cached: {stl_out} ({stl_out.stat().st_size // 1024} KB)")
-    except Exception as exc:
-        logger.error(f"STL generation failed for {cad_file_id} quality={quality}: {exc}")
-        raise self.retry(exc=exc, countdown=30, max_retries=2)
-
-
 @celery_app.task(bind=True, name="app.tasks.step_tasks.generate_gltf_geometry_task", queue="thumbnail_rendering", max_retries=1)
 def generate_gltf_geometry_task(self, cad_file_id: str):
-    """Export a GLB via Blender with material substitution and OCC sharp-edge data.
+    """Export a geometry GLB directly from STEP via OCC (no STL intermediary).
 
     Pipeline:
-      1. Reads sharp_edge_midpoints from cad_file.mesh_attributes (from OCC extraction)
-      2. Resolves material_map via alias lookup (part_name → SCHAEFFLER library material)
-      3. Runs Blender headless with export_gltf.py: STL → GLB with library materials + sharp edges
-      4. Falls back to trimesh (geometry-only, no materials) if Blender is unavailable
+      1. Reads STEP file directly (no STL needed)
+      2. Builds color_map from product.cad_part_materials (hex colors)
+      3. Runs export_step_to_gltf.py (Python/OCP): STEP → GLB with per-part colors
+      4. Stores result as gltf_geometry MediaAsset (replaces any existing one)
 
-    Replaces the existing gltf_geometry MediaAsset for this CadFile on each run.
+    Output is in meters, Y-up (glTF convention).
     """
     import json as _json
     import os as _os
     import subprocess as _subprocess
+    import sys as _sys
     from pathlib import Path as _Path
     from sqlalchemy import create_engine, select as _select
     from sqlalchemy.orm import Session
@@ -422,115 +371,68 @@ def generate_gltf_geometry_task(self, cad_file_id: str):
             logger.error("generate_gltf_geometry_task: no stored_path for %s", cad_file_id)
             return
         step_path_str = cad_file.stored_path
-        mesh_attrs = cad_file.mesh_attributes or {}
-        sharp_edge_midpoints = mesh_attrs.get("sharp_edge_midpoints", [])
 
-        # Load product materials for this CAD file
+        # Build hex color_map from product.cad_part_materials
         from app.domains.products.models import Product
         product = session.execute(
             _select(Product).where(Product.cad_file_id == cad_file.id)
         ).scalar_one_or_none()
 
-        raw_material_map: dict[str, str] = {}
+        color_map: dict[str, str] = {}
+        product_id = str(product.id) if product else None
         if product and product.cad_part_materials:
             for entry in product.cad_part_materials:
                 part_name = entry.get("part_name") or entry.get("name", "")
-                mat_name = entry.get("material_name") or entry.get("material", "")
-                if part_name and mat_name:
-                    raw_material_map[part_name] = mat_name
+                hex_color = entry.get("hex_color") or entry.get("color", "")
+                if part_name and hex_color:
+                    color_map[part_name] = hex_color
     eng.dispose()
 
-    # Resolve aliases: "Steel--Stahl" → "SCHAEFFLER_010101_Steel-Bare"
-    from app.services.material_service import resolve_material_map
-    material_map = resolve_material_map(raw_material_map)
-
-    # Get asset library .blend path from system settings
-    from app.services.template_service import get_material_library_path
-    asset_library_blend = get_material_library_path()
-
     step = _Path(step_path_str)
-    stl_path = step.parent / f"{step.stem}_low.stl"
-    if not stl_path.exists():
-        log_task_event(self.request.id, f"Failed: STL cache not found: {stl_path}", "error")
-        raise RuntimeError(f"STL cache not found: {stl_path}")
+    if not step.exists():
+        log_task_event(self.request.id, f"Failed: STEP file not found: {step}", "error")
+        raise RuntimeError(f"STEP file not found: {step}")
 
     output_path = step.parent / f"{step.stem}_geometry.glb"
 
     log_task_event(
         self.request.id,
-        f"Starting GLB export: {len(material_map)} materials, "
-        f"{len(sharp_edge_midpoints)} sharp-edge hints, "
-        f"library={'yes' if asset_library_blend else 'no'}",
+        f"Starting OCC GLB export: {len(color_map)} part colors",
         "info",
     )
 
-    # --- Blender path ---
-    blender_bin = _os.environ.get("BLENDER_BIN", "blender")
+    # Run export_step_to_gltf.py as a subprocess so OCP imports don't pollute worker state
     scripts_dir = _Path(_os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
-    script_path = scripts_dir / "export_gltf.py"
-    blender_ok = False
+    script_path = scripts_dir / "export_step_to_gltf.py"
 
-    if _Path(blender_bin).exists() and script_path.exists():
+    python_bin = _sys.executable
     cmd = [
-            blender_bin, "--background", "--python", str(script_path), "--",
-            "--stl_path", str(stl_path),
+        python_bin, str(script_path),
+        "--step_path", str(step),
         "--output_path", str(output_path),
-            "--material_map", _json.dumps(material_map),
-            "--sharp_edges_json", _json.dumps(sharp_edge_midpoints),
+        "--color_map", _json.dumps(color_map),
     ]
-        if asset_library_blend and _Path(asset_library_blend).exists():
-            cmd += ["--asset_library_blend", asset_library_blend]
 
     try:
-            result = _subprocess.run(cmd, capture_output=True, text=True, timeout=180)
-            if result.returncode == 0 and output_path.exists() and output_path.stat().st_size > 0:
-                blender_ok = True
-                logger.info("generate_gltf_geometry_task: Blender export succeeded (%s KB)",
-                            output_path.stat().st_size // 1024)
-            else:
-                logger.warning(
-                    "Blender GLB export failed (exit %d) — falling back to trimesh.\n"
-                    "STDOUT: %s\nSTDERR: %s",
-                    result.returncode, result.stdout[-1500:], result.stderr[-500:],
+        result = _subprocess.run(cmd, capture_output=True, text=True, timeout=120)
+        for line in result.stdout.splitlines():
+            logger.info("[occ-gltf] %s", line)
+        for line in result.stderr.splitlines():
+            logger.warning("[occ-gltf stderr] %s", line)
+
+        if result.returncode != 0 or not output_path.exists() or output_path.stat().st_size == 0:
+            raise RuntimeError(
+                f"export_step_to_gltf.py failed (exit {result.returncode}).\n"
+                f"STDERR: {result.stderr[-1000:]}"
             )
-        except Exception as exc:
-            logger.warning("Blender GLB export error (%s) — falling back to trimesh", exc)
-    else:
-        logger.warning(
-            "Blender not available at '%s' or script missing at '%s' — using trimesh fallback",
-            blender_bin, script_path,
-        )
-
-    # --- Trimesh fallback (geometry only, no materials) ---
-    if not blender_ok:
-        try:
-            import trimesh
-            import trimesh as _trimesh
-
-            def _process_mesh(m):
-                m.apply_scale(0.001)
-                try:
-                    _trimesh.smoothing.filter_laplacian(m, lamb=0.5, iterations=5)
-                except Exception:
-                    pass
-
-            mesh = trimesh.load(str(stl_path))
-            if hasattr(mesh, 'geometry'):
-                for sub in mesh.geometry.values():
-                    _process_mesh(sub)
-            else:
-                _process_mesh(mesh)
-            mesh.export(str(output_path))
-            log_task_event(self.request.id, "Trimesh fallback export completed (no materials)", "done")
     except Exception as exc:
         log_task_event(self.request.id, f"Failed: {exc}", "error")
-            logger.error("generate_gltf_geometry_task trimesh fallback failed: %s", exc)
+        logger.error("generate_gltf_geometry_task OCC export failed: %s", exc)
         raise self.retry(exc=exc, countdown=15)
-    else:
-        log_task_event(self.request.id, f"Blender GLB export completed: {output_path.name}", "done")
+
+    log_task_event(self.request.id, f"OCC GLB export completed: {output_path.name}", "done")
 
     # --- Store MediaAsset (replace existing gltf_geometry for this cad_file) ---
-    # 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
@@ -551,6 +453,7 @@ def generate_gltf_geometry_task(self, cad_file_id: str):
             _key = _key[len(_prefix):]
         asset = MediaAsset(
             cad_file_id=_uuid.UUID(cad_file_id),
+            product_id=_uuid.UUID(product_id) if product_id else None,
             asset_type=MediaAssetType.gltf_geometry,
             storage_key=_key,
             mime_type="model/gltf-binary",
@@ -565,6 +468,146 @@ def generate_gltf_geometry_task(self, cad_file_id: str):
     return {"glb_path": str(output_path), "asset_id": asset_id}
 
 
+@celery_app.task(
+    bind=True,
+    name="app.tasks.step_tasks.generate_gltf_production_task",
+    queue="thumbnail_rendering",
+    max_retries=2,
+)
+def generate_gltf_production_task(self, cad_file_id: str, product_id: str | None = None) -> dict:
+    """Generate a production GLB (Blender + PBR materials) from a geometry GLB via export_gltf.py.
+
+    1. Ensures a gltf_geometry MediaAsset exists (runs OCC export inline if not).
+    2. Resolves SCHAEFFLER material map for the CadFile's product.
+    3. Runs Blender headless with export_gltf.py → production GLB.
+    4. Stores result as gltf_production MediaAsset.
+    """
+    import json as _json
+    import os as _os
+    import subprocess as _subprocess
+    import uuid as _uuid
+    from pathlib import Path as _Path
+
+    from sqlalchemy import create_engine as _ce, delete as _del, select as _sel
+    from sqlalchemy.orm import Session as _Session
+
+    from app.config import settings as app_settings
+    from app.domains.media.models import MediaAsset, MediaAssetType
+    from app.services.render_blender import find_blender, is_blender_available
+
+    log_task_event(self.request.id, f"generate_gltf_production_task started for cad {cad_file_id}", "info")
+
+    _sync_url = app_settings.database_url.replace("+asyncpg", "")
+    _eng = _ce(_sync_url)
+
+    # --- 1. Resolve geometry GLB path from existing gltf_geometry MediaAsset ---
+    with _Session(_eng) as _sess:
+        _row = _sess.execute(
+            _sel(MediaAsset).where(
+                MediaAsset.cad_file_id == _uuid.UUID(cad_file_id),
+                MediaAsset.asset_type == MediaAssetType.gltf_geometry,
+            )
+        ).scalar_one_or_none()
+        geom_glb_key = _row.storage_key if _row else None
+
+    if not geom_glb_key:
+        # Trigger geometry generation first and retry this task
+        log_task_event(self.request.id, "No gltf_geometry asset found — queuing geometry task first", "info")
+        generate_gltf_geometry_task.delay(cad_file_id, product_id)
+        raise self.retry(exc=RuntimeError("gltf_geometry not yet available"), countdown=30, max_retries=2)
+
+    geom_glb_path = _Path(app_settings.upload_dir) / geom_glb_key
+    if not geom_glb_path.exists():
+        raise RuntimeError(f"Geometry GLB not found on disk: {geom_glb_path}")
+
+    # --- 2. Resolve material map (SCHAEFFLER library names) ---
+    from app.services.material_service import resolve_material_map
+
+    with _Session(_eng) as _sess:
+        from app.models.cad_file import CadFile as _CF
+        _cad = _sess.execute(_sel(_CF).where(_CF.id == _uuid.UUID(cad_file_id))).scalar_one_or_none()
+        raw_mat_map: dict = {}
+        if _cad and _cad.cad_part_materials:
+            raw_mat_map = _cad.cad_part_materials
+
+    mat_map = resolve_material_map(raw_mat_map)
+
+    # --- 3. Resolve asset library .blend path from system settings ---
+    from app.models.system_setting import SystemSetting
+    with _Session(_eng) as _sess:
+        _setting = _sess.execute(
+            _sel(SystemSetting).where(SystemSetting.key == "asset_library_blend")
+        ).scalar_one_or_none()
+        asset_library_blend = _setting.value if _setting and _setting.value else ""
+    _eng.dispose()
+
+    # Output path next to geometry GLB
+    output_path = geom_glb_path.parent / (geom_glb_path.stem.replace("_geometry", "") + "_production.glb")
+
+    scripts_dir = _Path(_os.environ.get("RENDER_SCRIPTS_DIR", "/render-scripts"))
+    export_script = scripts_dir / "export_gltf.py"
+
+    if not is_blender_available():
+        raise RuntimeError("Blender is not available — cannot generate production GLB")
+    if not export_script.exists():
+        raise RuntimeError(f"export_gltf.py not found at {export_script}")
+
+    blender_bin = find_blender()
+    cmd = [
+        blender_bin, "--background",
+        "--python", str(export_script),
+        "--",
+        "--glb_path", str(geom_glb_path),
+        "--output_path", str(output_path),
+        "--material_map", _json.dumps(mat_map),
+    ]
+    if asset_library_blend:
+        cmd += ["--asset_library_blend", asset_library_blend]
+
+    log_task_event(self.request.id, f"Running Blender export_gltf.py for {geom_glb_path.name}", "info")
+    try:
+        result = _subprocess.run(cmd, capture_output=True, text=True, timeout=300)
+        if result.returncode != 0:
+            raise RuntimeError(
+                f"export_gltf.py exited {result.returncode}:\n{result.stderr[-500:]}"
+            )
+    except Exception as exc:
+        log_task_event(self.request.id, f"Blender production GLB failed: {exc}", "error")
+        logger.error("generate_gltf_production_task Blender failed for cad %s: %s", cad_file_id, exc)
+        raise self.retry(exc=exc, countdown=30)
+
+    log_task_event(self.request.id, f"Production GLB exported: {output_path.name}", "done")
+
+    # --- 4. Store MediaAsset (replace existing gltf_production for this cad_file) ---
+    _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_production,
+            )
+        )
+        _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),
+            product_id=_uuid.UUID(product_id) if product_id else None,
+            asset_type=MediaAssetType.gltf_production,
+            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()
+
+    logger.info("generate_gltf_production_task: MediaAsset %s created for cad %s", asset_id, cad_file_id)
+    return {"glb_path": str(output_path), "asset_id": asset_id}
+
+
 @celery_app.task(bind=True, name="app.tasks.step_tasks.regenerate_thumbnail", queue="thumbnail_rendering")
 def regenerate_thumbnail(self, cad_file_id: str, part_colors: dict):
     """Regenerate thumbnail with per-part colours."""

frontend/src/api/cad.ts

@@ -67,30 +67,6 @@ export async function getCadObjects(cadFileId: string): Promise<CadObjects> {
   return res.data
 }
 
-/**
- * Download the cached STL for a CAD file as a file-save dialog.
- * quality: 'low' | 'high'
- * The backend returns a human-readable filename, but we derive it client-side too.
- */
-export async function downloadStl(cadFileId: string, quality: 'low' | 'high', suggestedName?: string): Promise<void> {
-  const res = await api.get<Blob>(`/cad/${cadFileId}/stl/${quality}`, {
-    responseType: 'blob',
-  })
-  const url = URL.createObjectURL(res.data)
-  const a = document.createElement('a')
-  a.href = url
-  a.download = suggestedName ? `${suggestedName}_${quality}.stl` : `model_${quality}.stl`
-  document.body.appendChild(a)
-  a.click()
-  document.body.removeChild(a)
-  URL.revokeObjectURL(url)
-}
-
-export async function generateStl(cadFileId: string, quality: 'low' | 'high'): Promise<{ task_id: string }> {
-  const res = await api.post<{ task_id: string }>(`/cad/${cadFileId}/generate-stl/${quality}`)
-  return res.data
-}
-
 /**
  * Ask the backend to re-queue STEP processing for a CAD file (admin only).
  * Returns the Celery task_id (or null if the worker is not available).
@@ -110,23 +86,14 @@ export interface GenerateGltfResponse {
   cad_file_id: string
 }
 
-/**
- * Queue GLB geometry export from existing STL cache (trimesh, no Blender).
- * The STL low-quality cache must already exist.
- */
+/** Queue geometry GLB export directly from STEP via OCC (no Blender, no STL). */
 export async function generateGltfGeometry(cadFileId: string): Promise<GenerateGltfResponse> {
   const res = await api.post<GenerateGltfResponse>(`/cad/${cadFileId}/generate-gltf-geometry`)
   return res.data
 }
 
-export const exportGltfColored = (id: string): Promise<void> =>
-  api.get(`/cad/${id}/export-gltf-colored`, { responseType: 'blob' }).then(r => {
-    const url = URL.createObjectURL(r.data)
-    const a = document.createElement('a')
-    a.href = url
-    a.download = `${id}_colored.glb`
-    document.body.appendChild(a)
-    a.click()
-    document.body.removeChild(a)
-    URL.revokeObjectURL(url)
-  })
+/** Queue production GLB export (Blender + PBR materials) from geometry GLB. */
+export async function generateGltfProduction(cadFileId: string): Promise<GenerateGltfResponse> {
+  const res = await api.post<GenerateGltfResponse>(`/cad/${cadFileId}/generate-gltf-production`)
+  return res.data
+}

frontend/src/api/products.ts

@@ -55,7 +55,6 @@ export interface Product {
   thumbnail_url: string | null
   render_image_url: string | null
   processing_status: string | null
-  stl_cached: string[]
   cad_parsed_objects: string[] | null
   cad_mesh_attributes?: {
     dimensions_mm?: { x: number; y: number; z: number }

frontend/src/components/cad/InlineCadViewer.tsx

@@ -31,7 +31,7 @@ function GlbModel({ url, wireframe }: { url: string; wireframe: boolean }) {
       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,
+          // Non-indexed geometry: 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.
@@ -208,7 +208,7 @@ export default function InlineCadViewer({
         className="btn-secondary text-xs"
         onClick={() => generateMut.mutate()}
         disabled={generateMut.isPending || generating}
-        title="Export STL to GLB and load 3D viewer"
+        title="Export geometry GLB from STEP via OCC and load 3D viewer"
       >
         <RefreshCw size={12} className={generating ? 'animate-spin' : ''} />
         {generating ? 'Generating…' : generateMut.isPending ? 'Queuing…' : 'Load 3D Model'}

frontend/src/pages/Admin.tsx

@@ -73,7 +73,6 @@ export default function AdminPage() {
     blender_eevee_samples: number
     threejs_render_size: number
     thumbnail_format: string
-    stl_quality: string
     blender_smooth_angle: number
     cycles_device: string
     blender_max_concurrent_renders: number
@@ -159,14 +158,6 @@ export default function AdminPage() {
     onError: (e: any) => toast.error(e.response?.data?.detail || 'Import failed'),
   })
 
-  const generateMissingStlsMut = useMutation({
-    mutationFn: () => api.post('/admin/settings/generate-missing-stls'),
-    onSuccess: (res) => {
-      toast.success(res.data.message || 'STL generation queued')
-    },
-    onError: (e: any) => toast.error(e.response?.data?.detail || 'Failed'),
-  })
-
   const reextractMetadataMut = useMutation({
     mutationFn: () => api.post('/admin/settings/reextract-metadata'),
     onSuccess: (res) => {
@@ -397,29 +388,6 @@ export default function AdminPage() {
                 </div>
               </div>
 
-              {/* STL quality */}
-              <div className="flex items-center gap-6 flex-wrap">
-                <span className="text-sm font-medium text-content-secondary w-28 shrink-0">STL quality</span>
-                {(['low', 'high'] as const).map((q) => (
-                  <button
-                    key={q}
-                    onClick={() => setBlenderDraft((d) => ({ ...d, stl_quality: q }))}
-                    className={`px-4 py-1.5 rounded-full border text-sm font-medium transition-colors ${
-                      blender.stl_quality === q
-                        ? 'bg-blue-600 text-white border-blue-600'
-                        : 'bg-surface text-content-secondary border-border-default hover:border-blue-400 hover:text-blue-600'
-                    }`}
-                  >
-                    {q === 'low' ? 'Low (fast)' : 'High (detailed)'}
-                  </button>
-                ))}
-                <p className="text-xs text-content-muted">
-                  {blender.stl_quality === 'high'
-                    ? 'Fine mesh (tol=0.01) — slower STEP→STL, sharper edges.'
-                    : 'Coarse mesh (tol=0.3) — faster, good for previews.'}
-                </p>
-              </div>
-
               {/* Smooth by angle */}
               <div className="flex items-center gap-4 flex-wrap">
                 <span className="text-sm font-medium text-content-secondary w-28 shrink-0">Smooth angle</span>
@@ -704,18 +672,6 @@ export default function AdminPage() {
                 </button>
                 <p className="text-xs text-content-muted">Registers existing renders &amp; CAD thumbnails in the Media Browser.</p>
               </div>
-              <div className="flex flex-col gap-1">
-                <button
-                  onClick={() => generateMissingStlsMut.mutate()}
-                  disabled={generateMissingStlsMut.isPending}
-                  className="btn-secondary text-sm w-full justify-start"
-                  title="Queue STL conversion for every low/high quality that is not yet cached on disk"
-                >
-                  <RefreshCw size={14} className={generateMissingStlsMut.isPending ? 'animate-spin' : ''} />
-                  {generateMissingStlsMut.isPending ? 'Queueing…' : 'Generate Missing STLs'}
-                </button>
-                <p className="text-xs text-content-muted">Generates low + high STL files for completed STEP files missing them.</p>
-              </div>
               <div className="flex flex-col gap-1">
                 <button
                   onClick={() => reextractMetadataMut.mutate()}

frontend/src/pages/CadPreview.tsx

@@ -96,8 +96,8 @@ export default function CadPreviewPage() {
           <Box size={48} className="text-gray-600" />
           <p className="text-white text-lg font-semibold">No 3D model available yet</p>
           <p className="text-gray-400 text-sm max-w-sm">
-            Generate a GLB file from the STEP cache to enable the 3D viewer.
-            The STL cache must exist (process the STEP file first).
+            Generate a geometry GLB from the STEP file to enable the 3D viewer.
+            Process the STEP file first to make it available.
           </p>
           {generating ? (
             <div className="flex items-center gap-2 text-gray-300 text-sm">
@@ -116,7 +116,7 @@ export default function CadPreviewPage() {
           )}
           {generateMutation.isError && (
             <p className="text-red-400 text-sm">
-              Failed to start generation. Check that the STL cache exists.
+              Failed to start generation. Make sure the STEP file has been processed.
             </p>
           )}
         </div>

frontend/src/pages/ProductDetail.tsx

@@ -18,7 +18,7 @@ import { listMaterials } from '../api/materials'
 import MaterialInput from '../components/shared/MaterialInput'
 import MaterialWizard from '../components/MaterialWizard'
 import { useAuthStore } from '../store/auth'
-import { downloadStl, generateStl, generateGltfGeometry, exportGltfColored } from '../api/cad'
+import { generateGltfGeometry, generateGltfProduction } from '../api/cad'
 import InlineCadViewer from '../components/cad/InlineCadViewer'
 
 function CadStatusBadge({ status }: { status: string | null }) {
@@ -290,11 +290,6 @@ export default function ProductDetailPage() {
     onError: (e: any) => toast.error(e.response?.data?.detail || 'Failed to delete'),
   })
 
-  const exportGltfColoredMut = useMutation({
-    mutationFn: () => exportGltfColored(product?.cad_file_id!),
-    onError: () => toast.error('GLB export failed'),
-  })
-
   const [editPositionDraft, setEditPositionDraft] = useState<Partial<RenderPosition>>({})
 
   const POSITION_PRESETS = [
@@ -526,160 +521,87 @@ export default function ProductDetailPage() {
 
         {product.cad_file_id ? (
           <div className="space-y-3">
-            {/* Inline 3D Viewer */}
+            {/* Two-column: viewer left, actions right */}
+            <div className="flex gap-4 items-start">
+              {/* Left: Inline 3D Viewer */}
+              <div className="flex-1 min-w-0">
                 <InlineCadViewer
                   cadFileId={product.cad_file_id}
                   thumbnailUrl={product.render_image_url || product.thumbnail_url}
                 />
+              </div>
+
+              {/* Right: Action buttons */}
+              <div className="flex flex-col gap-2 shrink-0 w-44">
+                <button
+                  className="btn-secondary text-xs w-full justify-start"
+                  onClick={() => navigate(`/cad/${product.cad_file_id}`)}
+                  title="Open interactive 3D viewer in full screen"
+                >
+                  <Cuboid size={12} />
+                  View Full Screen
+                </button>
 
-            {/* Action buttons */}
-            <div className="flex flex-wrap gap-2">
                 {isPrivileged && (
                   <>
+                    <div className="border-t border-border-light pt-2 mt-1 flex flex-col gap-2">
                       <div {...getRootProps()} className="cursor-pointer">
                         <input {...getInputProps()} />
-                    <button className="btn-secondary text-xs" disabled={cadUploadMut.isPending}>
+                        <button className="btn-secondary text-xs w-full justify-start" disabled={cadUploadMut.isPending}>
                           <Upload size={12} />
                           {cadUploadMut.isPending ? 'Uploading…' : 'Re-upload STEP'}
                         </button>
                       </div>
                       <button
-                    className="btn-secondary text-xs"
+                        className="btn-secondary text-xs w-full justify-start"
                         onClick={() => regenerateMut.mutate()}
                         disabled={regenerateMut.isPending}
-                    title="Re-render the thumbnail using the current part materials and the active thumbnail renderer — keeps the existing STEP parse data"
+                        title="Re-render thumbnail with current materials"
                       >
                         <RotateCcw size={12} />
-                    {regenerateMut.isPending ? 'Queuing…' : 'Regenerate thumbnail'}
+                        {regenerateMut.isPending ? 'Queuing…' : 'Regen thumbnail'}
                       </button>
                       <button
-                    className="btn-secondary text-xs"
+                        className="btn-secondary text-xs w-full justify-start"
                         onClick={() => reprocessMut.mutate()}
                         disabled={reprocessMut.isPending}
-                    title="Re-run full STEP processing: re-parse part names, regenerate thumbnail and glTF. Use this after re-uploading a STEP file."
+                        title="Re-parse STEP + regenerate thumbnail and glTF"
                       >
                         <RotateCcw size={12} />
                         {reprocessMut.isPending ? 'Queuing…' : 'Re-process STEP'}
                       </button>
-                  <button
-                    className="btn-secondary text-xs"
-                    onClick={() => navigate(`/cad/${product.cad_file_id}`)}
-                    title="Open interactive 3D viewer in full screen"
-                  >
-                    <Cuboid size={12} />
-                    View Full Screen
-                  </button>
-                  <button
-                    className="btn-secondary text-xs"
-                    onClick={() =>
-                      generateGltfGeometry(product.cad_file_id!)
-                        .then(() => toast.info('GLB geometry export queued'))
-                        .catch(() => toast.error('Failed to queue GLB export'))
-                    }
-                    title="Export geometry-only GLB from cached STL (trimesh, no Blender). Requires STL cache."
-                  >
-                    <Download size={12} />
-                    Generate GLB
-                  </button>
-                  {product?.processing_status === 'completed' && (
-                    <button
-                      onClick={() => exportGltfColoredMut.mutate()}
-                      disabled={exportGltfColoredMut.isPending}
-                      className="btn-secondary flex items-center gap-2 disabled:opacity-40 text-xs"
-                      title="Download GLB with PBR colors from material assignments"
-                    >
-                      <Download size={12} />
-                      {exportGltfColoredMut.isPending ? 'Exporting…' : 'GLB + Colors'}
-                    </button>
-                  )}
-                  <div className="flex items-center gap-1 pl-1 border-l border-border-light">
-                    <p className="text-xs text-content-muted font-medium">STL:</p>
-                    {(['low', 'high'] as const).map((q) =>
-                      product.stl_cached.includes(q) ? (
-                        <button
-                          key={q}
-                          className="btn-secondary text-xs"
-                          onClick={() => downloadStl(product.cad_file_id!, q, product.name_cad_modell || product.name || undefined)}
-                          title={q === 'low' ? 'Coarse mesh, tolerance 0.3 mm' : 'Fine mesh, tolerance 0.01 mm'}
-                        >
-                          <Download size={12} /> {q === 'low' ? 'Low' : 'High'}
-                        </button>
-                      ) : (
-                        <button
-                          key={q}
-                          className="btn-secondary text-xs opacity-60"
-                          onClick={() => generateStl(product.cad_file_id!, q).then(() => toast.info(`STL generation queued (${q} quality)`)).catch(() => toast.error('Failed to queue STL generation'))}
-                          title={`${q === 'low' ? 'Low' : 'High'}-quality STL not cached — click to generate`}
-                        >
-                          <RefreshCw size={12} /> Gen {q === 'low' ? 'Low' : 'High'}
-                        </button>
-                      )
-                    )}
-                  </div>
-                </>
-              )}
-              {!isPrivileged && product.cad_file_id && (
-                <button
-                  className="btn-secondary text-xs"
-                  onClick={() => navigate(`/cad/${product.cad_file_id}`)}
-                  title="Open interactive 3D viewer in full screen"
-                >
-                  <Cuboid size={12} />
-                  View Full Screen
-                </button>
-              )}
                     </div>
 
-            {/* Mesh attributes */}
-            {(() => {
-              // Prefer cad_mesh_attributes (reliably populated by API) over cad_file.mesh_attributes
-              const mesh_attrs: Record<string, unknown> = (product.cad_mesh_attributes ?? product.cad_file?.mesh_attributes) as Record<string, unknown> ?? {}
-              if (Object.keys(mesh_attrs).length === 0) return null
-              const dims = mesh_attrs.dimensions_mm as { x: number; y: number; z: number } | undefined
-              const bbox = mesh_attrs.bbox as { x?: number; y?: number; z?: number } | undefined
-              return (
-                <div className="mt-3 p-3 rounded-md border border-border-default bg-surface-alt">
-                  <p className="text-xs font-semibold text-content-muted mb-2 flex items-center gap-1">
-                    <Ruler size={12} />
-                    Geometry
-                  </p>
-                  <div className="grid grid-cols-2 gap-x-4 gap-y-1 text-xs">
-                    {dims != null && (
-                      <>
-                        <span className="text-content-muted">Dimensions</span>
-                        <span>{dims.x.toFixed(1)} × {dims.y.toFixed(1)} × {dims.z.toFixed(1)} mm</span>
-                      </>
-                    )}
-                    {dims == null && bbox != null && (
-                      <>
-                        <span className="text-content-muted">BBox</span>
-                        <span>
-                          {bbox.x?.toFixed(1)} × {bbox.y?.toFixed(1)} × {bbox.z?.toFixed(1)} mm
-                        </span>
-                      </>
-                    )}
-                    {(mesh_attrs.volume_mm3 as number | undefined) != null && (
-                      <>
-                        <span className="text-content-muted">Volume</span>
-                        <span>{((mesh_attrs.volume_mm3 as number) / 1000).toFixed(2)} cm³</span>
-                      </>
-                    )}
-                    {(mesh_attrs.surface_area_mm2 as number | undefined) != null && (
-                      <>
-                        <span className="text-content-muted">Surface</span>
-                        <span>{((mesh_attrs.surface_area_mm2 as number) / 100).toFixed(1)} cm²</span>
-                      </>
-                    )}
-                    {mesh_attrs.suggested_smooth_angle !== undefined && (
-                      <>
-                        <span className="text-content-muted">Sharp angle</span>
-                        <span>{mesh_attrs.suggested_smooth_angle as number}°</span>
+                    <div className="border-t border-border-light pt-2 mt-1 flex flex-col gap-2">
+                      <button
+                        className="btn-secondary text-xs w-full justify-start"
+                        onClick={() =>
+                          generateGltfGeometry(product.cad_file_id!)
+                            .then(() => toast.info('Geometry GLB export queued'))
+                            .catch(() => toast.error('Failed to queue GLB export'))
+                        }
+                        title="Export geometry GLB directly from STEP via OCC (no Blender)"
+                      >
+                        <Download size={12} />
+                        Generate Geometry GLB
+                      </button>
+                      <button
+                        className="btn-secondary text-xs w-full justify-start"
+                        onClick={() =>
+                          generateGltfProduction(product.cad_file_id!)
+                            .then(() => toast.info('Production GLB export queued'))
+                            .catch(() => toast.error('Failed to queue production GLB export'))
+                        }
+                        title="Export production GLB with PBR materials via Blender"
+                      >
+                        <Download size={12} />
+                        Generate Production GLB
+                      </button>
+                    </div>
                   </>
                 )}
               </div>
             </div>
-              )
-            })()}
 
             {/* Material assignments */}
             {isPrivileged && (

render-worker/scripts/blender_render.py

@@ -57,12 +57,12 @@ else:
 
 if len(argv) < 4:
     print("Usage: blender --background --python blender_render.py -- "
-          "<stl_path> <output_path> <width> <height> [engine] [samples] [smooth_angle] [cycles_device] [transparent_bg]")
+          "<glb_path> <output_path> <width> <height> [engine] [samples] [smooth_angle] [cycles_device] [transparent_bg]")
     sys.exit(1)
 
 import json as _json
 
-stl_path    = argv[0]
+glb_path    = argv[0]
 output_path = argv[1]
 width       = int(argv[2])
 height      = int(argv[3])
@@ -173,23 +173,7 @@ def _assign_palette_material(part_obj, index):
 import re as _re
 
 
-def _scale_mm_to_m(parts):
-    """Scale imported STL objects from mm to Blender metres (×0.001).
-
-    STEP/STL coordinates are in mm; Blender's default unit is metres.
-    Without scaling a 50 mm part appears as 50 m inside Blender — way too large
-    relative to any template environment designed in metric units.
-    """
-    if not parts:
-        return
-    bpy.ops.object.select_all(action='DESELECT')
-    for p in parts:
-        p.scale = (0.001, 0.001, 0.001)
-        p.location *= 0.001
-        p.select_set(True)
-    bpy.context.view_layer.objects.active = parts[0]
-    bpy.ops.object.transform_apply(scale=True, location=False, rotation=False)
-    print(f"[blender_render] scaled {len(parts)} parts mm→m (×0.001)")
+# _scale_mm_to_m removed: OCC GLB export produces coordinates in metres already.
 
 
 def _apply_rotation(parts, rx, ry, rz):
@@ -276,74 +260,26 @@ def _mark_sharp_and_seams(obj, smooth_angle_deg: float, sharp_edge_midpoints=Non
     bpy.ops.object.mode_set(mode='OBJECT')
 
 
-def _import_stl(stl_file):
-    """Import STL into Blender, using per-part STLs if available.
+def _import_glb(glb_file):
+    """Import OCC-generated GLB into Blender.
 
-    Checks for {stl_stem}_parts/manifest.json next to the STL file.
-    - Per-part mode: imports each part STL, names Blender object after STEP part name.
-    - Fallback: imports combined STL and splits by loose geometry.
+    OCC exports one mesh object per STEP part, already in metres.
+    Blender's native GLTF importer preserves part names.
 
-    Returns list of Blender mesh objects, centred at origin.
+    Returns list of Blender mesh objects, centred at world origin.
     """
-    stl_dir = os.path.dirname(stl_file)
-    stl_stem = os.path.splitext(os.path.basename(stl_file))[0]
-    parts_dir = os.path.join(stl_dir, stl_stem + "_parts")
-    manifest_path = os.path.join(parts_dir, "manifest.json")
-
-    parts = []
-
-    if os.path.isfile(manifest_path):
-        # ── Per-part mode ────────────────────────────────────────────────
-        try:
-            with open(manifest_path, "r") as f:
-                manifest = _json.loads(f.read())
-            part_entries = manifest.get("parts", [])
-        except Exception as e:
-            print(f"[blender_render] WARNING: failed to read manifest: {e}")
-            part_entries = []
-
-        if part_entries:
-            for entry in part_entries:
-                part_file = os.path.join(parts_dir, entry["file"])
-                part_name = entry["name"]
-                if not os.path.isfile(part_file):
-                    print(f"[blender_render] WARNING: part STL missing: {part_file}")
-                    continue
-
     bpy.ops.object.select_all(action='DESELECT')
-                bpy.ops.wm.stl_import(filepath=part_file)
-                imported = bpy.context.selected_objects
-                if imported:
-                    obj = imported[0]
-                    obj.name = part_name
-                    if obj.data:
-                        obj.data.name = part_name
-                    parts.append(obj)
+    bpy.ops.import_scene.gltf(filepath=glb_file)
+    parts = [o for o in bpy.context.selected_objects if o.type == 'MESH']
 
-            if parts:
-                print(f"[blender_render] imported {len(parts)} named parts from per-part STLs")
-
-    # ── Fallback: combined STL + separate by loose ───────────────────────
     if not parts:
-        bpy.ops.wm.stl_import(filepath=stl_file)
-        obj = bpy.context.selected_objects[0] if bpy.context.selected_objects else None
-        if obj is None:
-            print(f"ERROR: No objects imported from {stl_file}")
+        print(f"ERROR: No mesh objects imported from {glb_file}")
         sys.exit(1)
 
-        bpy.context.view_layer.objects.active = obj
-        bpy.ops.object.origin_set(type='ORIGIN_GEOMETRY', center='BOUNDS')
-        obj.location = (0.0, 0.0, 0.0)
+    print(f"[blender_render] imported {len(parts)} part(s) from GLB: "
+          f"{[p.name for p in parts[:5]]}")
 
-        bpy.ops.object.mode_set(mode='EDIT')
-        bpy.ops.mesh.separate(type='LOOSE')
-        bpy.ops.object.mode_set(mode='OBJECT')
-
-        parts = list(bpy.context.selected_objects)
-        print(f"[blender_render] fallback: separated into {len(parts)} part(s)")
-        return parts
-
-    # ── Centre per-part imports at origin (combined bbox) ────────────────
+    # Centre combined bbox at world origin
     all_corners = []
     for p in parts:
         all_corners.extend(p.matrix_world @ Vector(c) for c in p.bound_box)
@@ -453,10 +389,8 @@ if use_template:
     # Find or create target collection
     target_col = _ensure_collection(target_collection)
 
-    # Import and split STL
-    parts = _import_stl(stl_path)
-    # Scale mm→m: STEP coords are mm, Blender default unit is metres
-    _scale_mm_to_m(parts)
+    # Import OCC GLB (already in metres, one object per STEP part)
+    parts = _import_glb(glb_path)
     # Apply render position rotation (before camera/bbox calculations)
     _apply_rotation(parts, rotation_x, rotation_y, rotation_z)
 
@@ -538,9 +472,8 @@ else:
     # ── MODE A: Factory settings (original behavior) ─────────────────────────
     needs_auto_camera = True
     bpy.ops.wm.read_factory_settings(use_empty=True)
-    parts = _import_stl(stl_path)
-    # Scale mm→m: STEP coords are mm, Blender default unit is metres
-    _scale_mm_to_m(parts)
+    # Import OCC GLB (already in metres, one object per STEP part)
+    parts = _import_glb(glb_path)
     # Apply render position rotation (before camera/bbox calculations)
     _apply_rotation(parts, rotation_x, rotation_y, rotation_z)
 

render-worker/scripts/export_blend.py

@@ -1,14 +1,14 @@
-"""Blender headless script: export a STEP-derived scene as a production .blend.
+"""Blender headless script: export a geometry GLB as a production .blend.
 
 Usage:
     blender --background --python export_blend.py -- \\
-        --stl_path /path/to/file.stl \\
+        --glb_path /path/to/geometry.glb \\
         --output_path /path/to/output.blend \\
         [--asset_library_blend /path/to/library.blend] \\
         [--material_map '{"SrcMat": "LibMat"}']
 
 The script:
-1. Imports the STL file (with mm→m scale).
+1. Imports the geometry GLB (already in metres, Y-up).
 2. Optionally applies asset library materials from a .blend.
 3. Packs all external data.
 4. Saves a copy as the output .blend.
@@ -28,7 +28,8 @@ def parse_args() -> argparse.Namespace:
         sys.exit(1)
     rest = argv[argv.index("--") + 1:]
     parser = argparse.ArgumentParser()
-    parser.add_argument("--stl_path", required=True)
+    parser.add_argument("--glb_path", required=True,
+                        help="Geometry GLB from export_step_to_gltf.py (already in metres)")
     parser.add_argument("--output_path", required=True)
     parser.add_argument("--asset_library_blend", default=None)
     parser.add_argument("--material_map", default="{}")
@@ -44,14 +45,8 @@ def main() -> None:
     # Clean scene
     bpy.ops.wm.read_factory_settings(use_empty=True)
 
-    # Import STL
-    bpy.ops.import_mesh.stl(filepath=args.stl_path)
-
-    # Scale mm → m
-    for obj in bpy.context.selected_objects:
-        obj.scale = (0.001, 0.001, 0.001)
-        bpy.context.view_layer.objects.active = obj
-        bpy.ops.object.transform_apply(scale=True)
+    # Import geometry GLB (metres, Y-up — no rescaling needed)
+    bpy.ops.import_scene.gltf(filepath=args.glb_path)
 
     # Apply asset library materials if provided
     if args.asset_library_blend and material_map:

render-worker/scripts/export_gltf.py

@@ -27,78 +27,30 @@ def parse_args() -> argparse.Namespace:
         sys.exit(1)
     rest = argv[argv.index("--") + 1:]
     parser = argparse.ArgumentParser()
-    parser.add_argument("--stl_path", required=True)
+    parser.add_argument("--glb_path", required=True,
+                        help="Geometry GLB from export_step_to_gltf.py (already in metres)")
     parser.add_argument("--output_path", required=True)
     parser.add_argument("--asset_library_blend", default=None)
     parser.add_argument("--material_map", default="{}")
-    parser.add_argument("--sharp_edges_json", default="[]",
-                        help="JSON array of [x, y, z] midpoints (mm) to mark as sharp edges")
     return parser.parse_args(rest)
 
 
-def mark_sharp_edges_by_proximity(midpoints_mm: list, threshold_mm: float = 1.0) -> None:
-    """Mark Blender mesh edges as sharp based on proximity to OCC-derived midpoints.
-
-    midpoints_mm: list of [x, y, z] in mm (from OCC coordinate space).
-    After STL import + scale-apply (mm→m), Blender vertices are in meters, so we
-    convert the edge midpoint back to mm before comparing.
-    threshold_mm: snap distance in mm (default 1.0 mm).
-    """
-    if not midpoints_mm:
-        return
-
-    import bpy  # type: ignore[import]
-    import math
-
-    for obj in bpy.data.objects:
-        if obj.type != "MESH":
-            continue
-        mesh = obj.data
-        # Blender 4.1+ removed use_auto_smooth — use shade_smooth_by_angle instead
-        bpy.context.view_layer.objects.active = obj
-        obj.select_set(True)
-        try:
-            bpy.ops.object.shade_smooth_by_angle(angle=math.radians(30))
-        except Exception:
-            pass  # fallback: stay flat-shaded
-        mw = obj.matrix_world
-        for edge in mesh.edges:
-            v1 = mw @ mesh.vertices[edge.vertices[0]].co
-            v2 = mw @ mesh.vertices[edge.vertices[1]].co
-            # Convert Blender meters → mm for comparison
-            mid_mm = [
-                (v1.x + v2.x) / 2 * 1000,
-                (v1.y + v2.y) / 2 * 1000,
-                (v1.z + v2.z) / 2 * 1000,
-            ]
-            for hint in midpoints_mm:
-                dist_sq = sum((a - b) ** 2 for a, b in zip(mid_mm, hint))
-                if dist_sq < threshold_mm ** 2:
-                    edge.use_edge_sharp = True
-                    break
-
-
 def main() -> None:
     args = parse_args()
     material_map: dict = json.loads(args.material_map)
-    sharp_edge_midpoints: list = json.loads(args.sharp_edges_json)
 
     import bpy  # type: ignore[import]
+    import math as _math
 
     # Clean scene
     bpy.ops.wm.read_factory_settings(use_empty=True)
 
-    # Import STL (bpy.ops.wm.stl_import is the Blender 4.0+ API)
-    bpy.ops.wm.stl_import(filepath=args.stl_path)
-
-    # Scale mm → m
-    for obj in bpy.context.selected_objects:
-        obj.scale = (0.001, 0.001, 0.001)
-        bpy.context.view_layer.objects.active = obj
-        bpy.ops.object.transform_apply(scale=True)
+    # Import geometry GLB from export_step_to_gltf.py (already in metres, Y-up)
+    bpy.ops.import_scene.gltf(filepath=args.glb_path)
+    print(f"Imported geometry GLB: {args.glb_path} "
+          f"({len([o for o in bpy.data.objects if o.type == 'MESH'])} mesh objects)")
 
     # Apply smooth shading with 30° angle threshold (Blender 4.1+ API)
-    import math as _math
     for obj in bpy.data.objects:
         if obj.type == "MESH":
             bpy.context.view_layer.objects.active = obj
@@ -108,37 +60,30 @@ def main() -> None:
             except Exception:
                 pass
 
-    # Mark sharp edges for better UV seams
-    if sharp_edge_midpoints:
-        mark_sharp_edges_by_proximity(sharp_edge_midpoints)
-        print(f"Marked sharp edges from {len(sharp_edge_midpoints)} hint points")
-
     # Apply asset library materials if provided.
-    # link=False (append) is required for GLB export: the GLTF exporter can only
-    # traverse local (appended) Principled BSDF node trees to extract PBR values.
-    # Linked materials are external references whose node data is not accessible.
+    # link=False (append) is required: the GLTF exporter can only traverse
+    # local (appended) Principled BSDF node trees to extract PBR values.
     if args.asset_library_blend and material_map:
         import os
         sys.path.insert(0, os.path.dirname(__file__))
         from asset_library import apply_asset_library_materials
         apply_asset_library_materials(args.asset_library_blend, material_map, link=False)
 
-    # Export GLB with full PBR material data
-    # Note: export_colors was removed in Blender 4.x — do not pass it.
+    # Export production GLB with full PBR material data
     try:
         bpy.ops.export_scene.gltf(
             filepath=args.output_path,
             export_format="GLB",
             export_apply=True,
             use_selection=False,
-            export_materials="EXPORT",       # export all materials (Principled BSDF → glTF PBR)
-            export_image_format="AUTO",      # embed textures (base color, normal, roughness maps)
+            export_materials="EXPORT",
+            export_image_format="AUTO",
         )
     except Exception as exc:
         print(f"GLB export failed: {exc}", file=sys.stderr)
         sys.exit(1)
 
-    print(f"GLB exported to {args.output_path}")
+    print(f"Production GLB exported to {args.output_path}")
 
 
 try:

render-worker/scripts/export_step_to_gltf.py

@@ -0,0 +1,232 @@
+"""OCC-native STEP → GLB export script.
+
+Reads a STEP file via OCP/XCAF (preserving part names and embedded colors),
+tessellates with BRepMesh, optionally applies per-part hex colors, and writes
+a binary GLB in meters (Y-up, glTF convention).
+
+No Blender required. Uses the same OCP bindings that cadquery ships with.
+
+Usage:
+    python3 export_step_to_gltf.py \
+        --step_path /path/to/file.stp \
+        --output_path /path/to/output.glb \
+        [--linear_deflection 0.1] \
+        [--angular_deflection 0.5] \
+        [--color_map '{"RingInner": "#4C9BE8", "RingOuter": "#E85B4C"}']
+
+Exit 0 on success, exit 1 on failure.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+import traceback
+from pathlib import Path
+
+PALETTE_HEX = [
+    "#4C9BE8", "#E85B4C", "#4CBE72", "#E8A84C", "#A04CE8",
+    "#4CD4E8", "#E84CA8", "#7EC850", "#E86B30", "#5088C8",
+]
+
+
+def parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--step_path", required=True)
+    parser.add_argument("--output_path", required=True)
+    parser.add_argument(
+        "--linear_deflection", type=float, default=0.1,
+        help="OCC linear deflection for tessellation (mm). Smaller = finer mesh. Default 0.1",
+    )
+    parser.add_argument(
+        "--angular_deflection", type=float, default=0.5,
+        help="OCC angular deflection (radians). Default 0.5",
+    )
+    parser.add_argument(
+        "--color_map", default="{}",
+        help='JSON dict mapping part name → hex color, e.g. \'{"Ring": "#4C9BE8"}\'',
+    )
+    return parser.parse_args()
+
+
+def _hex_to_occ_color(hex_color: str):
+    """Convert '#RRGGBB' → Quantity_Color (linear float)."""
+    from OCP.Quantity import Quantity_Color, Quantity_TOC_RGB
+    h = hex_color.lstrip("#")
+    if len(h) < 6:
+        return Quantity_Color(0.7, 0.7, 0.7, Quantity_TOC_RGB)
+    r = int(h[0:2], 16) / 255.0
+    g = int(h[2:4], 16) / 255.0
+    b = int(h[4:6], 16) / 255.0
+    return Quantity_Color(r, g, b, Quantity_TOC_RGB)
+
+
+def _apply_color_map(shape_tool, color_tool, free_labels, color_map: dict) -> None:
+    """Apply hex colors from color_map to matching shapes by name (case-insensitive substring)."""
+    from OCP.TDF import TDF_LabelSequence
+    from OCP.TDataStd import TDataStd_Name
+    from OCP.XCAFDoc import XCAFDoc_ShapeTool
+
+    # XCAFDoc_ColorType: XCAFDoc_ColorGen=0, XCAFDoc_ColorSurf=1, XCAFDoc_ColorCurv=2
+    try:
+        from OCP.XCAFDoc import XCAFDoc_ColorSurf as COLOR_SURF
+    except ImportError:
+        COLOR_SURF = 1  # integer fallback
+
+    def _visit(label) -> None:
+        name_attr = TDataStd_Name()
+        name = ""
+        if label.FindAttribute(TDataStd_Name.GetID_s(), name_attr):
+            name = name_attr.Get().ToExtString()
+
+        if name:
+            for part_name, hex_color in color_map.items():
+                if part_name.lower() in name.lower() or name.lower() in part_name.lower():
+                    color_tool.SetColor(label, _hex_to_occ_color(hex_color), COLOR_SURF)
+                    break
+
+        components = TDF_LabelSequence()
+        XCAFDoc_ShapeTool.GetComponents_s(label, components)
+        for i in range(1, components.Length() + 1):
+            _visit(components.Value(i))
+
+    for i in range(1, free_labels.Length() + 1):
+        _visit(free_labels.Value(i))
+
+
+def _apply_palette_colors(shape_tool, color_tool, free_labels) -> None:
+    """Assign palette colors to leaf shapes when no color_map is provided."""
+    from OCP.TDF import TDF_LabelSequence
+    from OCP.XCAFDoc import XCAFDoc_ShapeTool
+
+    try:
+        from OCP.XCAFDoc import XCAFDoc_ColorSurf as COLOR_SURF
+    except ImportError:
+        COLOR_SURF = 1
+
+    leaves: list = []
+
+    def _collect(label) -> None:
+        components = TDF_LabelSequence()
+        XCAFDoc_ShapeTool.GetComponents_s(label, components)
+        if components.Length() == 0:
+            leaves.append(label)
+        else:
+            for i in range(1, components.Length() + 1):
+                _collect(components.Value(i))
+
+    for i in range(1, free_labels.Length() + 1):
+        _collect(free_labels.Value(i))
+
+    for idx, label in enumerate(leaves):
+        occ_color = _hex_to_occ_color(PALETTE_HEX[idx % len(PALETTE_HEX)])
+        color_tool.SetColor(label, occ_color, COLOR_SURF)
+
+
+def main() -> None:
+    args = parse_args()
+    color_map: dict = json.loads(args.color_map)
+
+    from OCP.STEPCAFControl import STEPCAFControl_Reader
+    from OCP.TDocStd import TDocStd_Document
+    from OCP.XCAFApp import XCAFApp_Application
+    from OCP.XCAFDoc import XCAFDoc_DocumentTool
+    from OCP.TCollection import TCollection_ExtendedString, TCollection_AsciiString
+    from OCP.TDF import TDF_LabelSequence
+    from OCP.BRepMesh import BRepMesh_IncrementalMesh
+    from OCP.IFSelect import IFSelect_RetDone
+    from OCP.Message import Message_ProgressRange
+
+    # --- Init XDE document ---
+    app = XCAFApp_Application.GetApplication_s()
+    doc = TDocStd_Document(TCollection_ExtendedString("MDTV-CAF"))
+    app.InitDocument(doc)
+
+    # --- Read STEP into XDE (preserves part names + embedded colors) ---
+    reader = STEPCAFControl_Reader()
+    reader.SetNameMode(True)
+    reader.SetColorMode(True)
+    reader.SetLayerMode(True)
+    status = reader.ReadFile(args.step_path)
+    if status != IFSelect_RetDone:
+        print(f"ERROR: STEPCAFControl_Reader failed (status={status})", file=sys.stderr)
+        sys.exit(1)
+    reader.Transfer(doc)
+
+    shape_tool = XCAFDoc_DocumentTool.ShapeTool_s(doc.Main())
+    color_tool = XCAFDoc_DocumentTool.ColorTool_s(doc.Main())
+
+    # --- Tessellate all free shapes ---
+    free_labels = TDF_LabelSequence()
+    shape_tool.GetFreeShapes(free_labels)
+    print(f"Found {free_labels.Length()} root shape(s), tessellating "
+          f"(linear={args.linear_deflection}mm, angular={args.angular_deflection}rad) …")
+
+    for i in range(1, free_labels.Length() + 1):
+        shape = shape_tool.GetShape_s(free_labels.Value(i))
+        if not shape.IsNull():
+            BRepMesh_IncrementalMesh(
+                shape,
+                args.linear_deflection,
+                False,   # isRelative
+                args.angular_deflection,
+                True,    # isInParallel
+            )
+
+    # --- Apply colors ---
+    if color_map:
+        _apply_color_map(shape_tool, color_tool, free_labels, color_map)
+        print(f"Applied color_map ({len(color_map)} entries)")
+    else:
+        _apply_palette_colors(shape_tool, color_tool, free_labels)
+        print("Applied palette colors (no color_map provided)")
+
+    # --- Scale shapes mm → m before GLB export ---
+    # RWMesh_CoordinateSystemConverter is not wrapped in OCP Python bindings.
+    # Pre-scale each free shape by 0.001 (mm → m) using BRepBuilderAPI_Transform.
+    from OCP.gp import gp_Trsf
+    from OCP.BRepBuilderAPI import BRepBuilderAPI_Transform
+
+    trsf = gp_Trsf()
+    trsf.SetScaleFactor(0.001)
+
+    for i in range(1, free_labels.Length() + 1):
+        label = free_labels.Value(i)
+        orig_shape = shape_tool.GetShape_s(label)
+        if not orig_shape.IsNull():
+            scaled = BRepBuilderAPI_Transform(orig_shape, trsf, True).Shape()
+            shape_tool.SetShape(label, scaled)
+
+    print("Shapes scaled mm → m")
+
+    # --- Export GLB via RWGltf_CafWriter ---
+    from OCP.RWGltf import RWGltf_CafWriter
+
+    writer = RWGltf_CafWriter(TCollection_AsciiString(args.output_path), True)  # True = binary GLB
+    # Z-up → Y-up rotation is applied by RWGltf_CafWriter by default (OCC 7.6+).
+
+    # Perform export
+    try:
+        from OCP.TColStd import TColStd_IndexedDataMapOfStringString
+        metadata = TColStd_IndexedDataMapOfStringString()
+        ok = writer.Perform(doc, metadata, Message_ProgressRange())
+    except TypeError:
+        # Older API without metadata dict
+        ok = writer.Perform(doc, Message_ProgressRange())
+
+    out = Path(args.output_path)
+    if not ok or not out.exists() or out.stat().st_size == 0:
+        print(f"ERROR: RWGltf_CafWriter.Perform returned ok={ok}, file exists={out.exists()}",
+              file=sys.stderr)
+        sys.exit(1)
+
+    print(f"GLB exported: {out.name} ({out.stat().st_size // 1024} KB)")
+
+
+try:
+    main()
+except SystemExit:
+    raise
+except Exception:
+    traceback.print_exc()
+    sys.exit(1)

render-worker/scripts/still_render.py

@@ -87,23 +87,7 @@ def _apply_smooth(part_obj, angle_deg):
 import re as _re
 
 
-def _scale_mm_to_m(parts):
-    """Scale imported STL objects from mm to Blender metres (×0.001).
-
-    STEP/STL coordinates are in mm; Blender's default unit is metres.
-    Without scaling a 50 mm part appears as 50 m inside Blender — way too large
-    relative to any template environment designed in metric units.
-    """
-    if not parts:
-        return
-    bpy.ops.object.select_all(action='DESELECT')
-    for p in parts:
-        p.scale = (0.001, 0.001, 0.001)
-        p.location *= 0.001
-        p.select_set(True)
-    bpy.context.view_layer.objects.active = parts[0]
-    bpy.ops.object.transform_apply(scale=True, location=False, rotation=False)
-    print(f"[still_render] scaled {len(parts)} parts mm→m (×0.001)")
+# _scale_mm_to_m removed: OCC GLB export produces coordinates in metres already.
 
 
 def _apply_rotation(parts, rx, ry, rz):
@@ -209,74 +193,24 @@ def _mark_sharp_and_seams(obj, smooth_angle_deg: float, sharp_edge_midpoints=Non
     bpy.ops.object.mode_set(mode='OBJECT')
 
 
-def _import_stl(stl_file):
-    """Import STL into Blender, using per-part STLs if available.
+def _import_glb(glb_file):
+    """Import OCC-generated GLB into Blender.
 
-    Checks for {stl_stem}_parts/manifest.json next to the STL file.
-    - Per-part mode: imports each part STL, names Blender object after STEP part name.
-    - Fallback: imports combined STL and splits by loose geometry.
-
-    Returns list of Blender mesh objects, centred at origin.
+    OCC exports one mesh object per STEP part, already in metres.
+    Returns list of Blender mesh objects, centred at world origin.
     """
-    stl_dir = os.path.dirname(stl_file)
-    stl_stem = os.path.splitext(os.path.basename(stl_file))[0]
-    parts_dir = os.path.join(stl_dir, stl_stem + "_parts")
-    manifest_path = os.path.join(parts_dir, "manifest.json")
-
-    parts = []
-
-    if os.path.isfile(manifest_path):
-        # ── Per-part mode ────────────────────────────────────────────────
-        try:
-            with open(manifest_path, "r") as f:
-                manifest = json.loads(f.read())
-            part_entries = manifest.get("parts", [])
-        except Exception as e:
-            print(f"[still_render] WARNING: failed to read manifest: {e}")
-            part_entries = []
-
-        if part_entries:
-            for entry in part_entries:
-                part_file = os.path.join(parts_dir, entry["file"])
-                part_name = entry["name"]
-                if not os.path.isfile(part_file):
-                    print(f"[still_render] WARNING: part STL missing: {part_file}")
-                    continue
-
     bpy.ops.object.select_all(action='DESELECT')
-                bpy.ops.wm.stl_import(filepath=part_file)
-                imported = bpy.context.selected_objects
-                if imported:
-                    obj = imported[0]
-                    obj.name = part_name
-                    if obj.data:
-                        obj.data.name = part_name
-                    parts.append(obj)
+    bpy.ops.import_scene.gltf(filepath=glb_file)
+    parts = [o for o in bpy.context.selected_objects if o.type == 'MESH']
 
-            if parts:
-                print(f"[still_render] imported {len(parts)} named parts from per-part STLs")
-
-    # ── Fallback: combined STL + separate by loose ───────────────────────
     if not parts:
-        bpy.ops.wm.stl_import(filepath=stl_file)
-        obj = bpy.context.selected_objects[0] if bpy.context.selected_objects else None
-        if obj is None:
-            print(f"ERROR: No objects imported from {stl_file}")
+        print(f"ERROR: No mesh objects imported from {glb_file}")
         sys.exit(1)
 
-        bpy.context.view_layer.objects.active = obj
-        bpy.ops.object.origin_set(type='ORIGIN_GEOMETRY', center='BOUNDS')
-        obj.location = (0.0, 0.0, 0.0)
+    print(f"[still_render] imported {len(parts)} part(s) from GLB: "
+          f"{[p.name for p in parts[:5]]}")
 
-        bpy.ops.object.mode_set(mode='EDIT')
-        bpy.ops.mesh.separate(type='LOOSE')
-        bpy.ops.object.mode_set(mode='OBJECT')
-
-        parts = list(bpy.context.selected_objects)
-        print(f"[still_render] fallback: separated into {len(parts)} part(s)")
-        return parts
-
-    # ── Centre per-part imports at origin (combined bbox) ────────────────
+    # Centre combined bbox at world origin
     all_corners = []
     for p in parts:
         all_corners.extend(p.matrix_world @ Vector(c) for c in p.bound_box)
@@ -376,7 +310,7 @@ def main():
     argv = sys.argv
     args = argv[argv.index("--") + 1:]
 
-    stl_path = args[0]
+    glb_path = args[0]
     output_path = args[1]
     width = int(args[2])
     height = int(args[3])
@@ -460,10 +394,8 @@ def main():
         # Find or create target collection
         target_col = _ensure_collection(target_collection)
 
-        # Import and split STL
-        parts = _import_stl(stl_path)
-        # Scale mm→m: STEP coords are mm, Blender default unit is metres
-        _scale_mm_to_m(parts)
+        # Import OCC GLB (already in metres, one object per STEP part)
+        parts = _import_glb(glb_path)
         # Apply render position rotation (before camera/bbox calculations)
         _apply_rotation(parts, rotation_x, rotation_y, rotation_z)
         # Apply OCC topology-based shading overrides
@@ -562,9 +494,7 @@ def main():
         needs_auto_camera = True
         bpy.ops.wm.read_factory_settings(use_empty=True)
 
-        parts = _import_stl(stl_path)
-        # Scale mm→m: STEP coords are mm, Blender default unit is metres
-        _scale_mm_to_m(parts)
+        parts = _import_glb(glb_path)
         # Apply render position rotation (before camera/bbox calculations)
         _apply_rotation(parts, rotation_x, rotation_y, rotation_z)
         # Apply OCC topology-based shading overrides
@@ -839,7 +769,7 @@ def main():
             draw.rectangle([0, 0, W - 1, bar_h - 1], fill=(0, 137, 61, 255))
 
             # Model name strip at bottom
-            model_name = os.path.splitext(os.path.basename(stl_path))[0]
+            model_name = os.path.splitext(os.path.basename(glb_path))[0]
             label_h = max(20, H // 20)
             img.alpha_composite(
                 Image.new("RGBA", (W, label_h), (30, 30, 30, 180)),

render-worker/scripts/turntable_render.py

@@ -138,23 +138,7 @@ def _set_fcurves_linear(action):
                 kp.interpolation = 'LINEAR'
 
 
-def _scale_mm_to_m(parts):
-    """Scale imported STL objects from mm to Blender metres (×0.001).
-
-    STEP/STL coordinates are in mm; Blender's default unit is metres.
-    Without scaling a 50 mm part appears as 50 m inside Blender — way too large
-    relative to any template environment designed in metric units.
-    """
-    if not parts:
-        return
-    bpy.ops.object.select_all(action='DESELECT')
-    for p in parts:
-        p.scale = (0.001, 0.001, 0.001)
-        p.location *= 0.001
-        p.select_set(True)
-    bpy.context.view_layer.objects.active = parts[0]
-    bpy.ops.object.transform_apply(scale=True, location=False, rotation=False)
-    print(f"[turntable_render] scaled {len(parts)} parts mm→m (×0.001)")
+# _scale_mm_to_m removed: OCC GLB export produces coordinates in metres already.
 
 
 def _apply_mesh_attributes(objects: list, mesh_attributes: dict) -> None:
@@ -179,74 +163,24 @@ def _apply_mesh_attributes(objects: list, mesh_attributes: dict) -> None:
         obj.data.auto_smooth_angle = threshold_rad
 
 
-def _import_stl(stl_file):
-    """Import STL into Blender, using per-part STLs if available.
+def _import_glb(glb_file):
+    """Import OCC-generated GLB into Blender.
 
-    Checks for {stl_stem}_parts/manifest.json next to the STL file.
-    - Per-part mode: imports each part STL, names Blender object after STEP part name.
-    - Fallback: imports combined STL and splits by loose geometry.
-
-    Returns list of Blender mesh objects, centred at origin.
+    OCC exports one mesh object per STEP part, already in metres.
+    Returns list of Blender mesh objects, centred at world origin.
     """
-    stl_dir = os.path.dirname(stl_file)
-    stl_stem = os.path.splitext(os.path.basename(stl_file))[0]
-    parts_dir = os.path.join(stl_dir, stl_stem + "_parts")
-    manifest_path = os.path.join(parts_dir, "manifest.json")
-
-    parts = []
-
-    if os.path.isfile(manifest_path):
-        # ── Per-part mode ────────────────────────────────────────────────
-        try:
-            with open(manifest_path, "r") as f:
-                manifest = json.loads(f.read())
-            part_entries = manifest.get("parts", [])
-        except Exception as e:
-            print(f"[turntable_render] WARNING: failed to read manifest: {e}")
-            part_entries = []
-
-        if part_entries:
-            for entry in part_entries:
-                part_file = os.path.join(parts_dir, entry["file"])
-                part_name = entry["name"]
-                if not os.path.isfile(part_file):
-                    print(f"[turntable_render] WARNING: part STL missing: {part_file}")
-                    continue
-
     bpy.ops.object.select_all(action='DESELECT')
-                bpy.ops.wm.stl_import(filepath=part_file)
-                imported = bpy.context.selected_objects
-                if imported:
-                    obj = imported[0]
-                    obj.name = part_name
-                    if obj.data:
-                        obj.data.name = part_name
-                    parts.append(obj)
+    bpy.ops.import_scene.gltf(filepath=glb_file)
+    parts = [o for o in bpy.context.selected_objects if o.type == 'MESH']
 
-            if parts:
-                print(f"[turntable_render] imported {len(parts)} named parts from per-part STLs")
-
-    # ── Fallback: combined STL + separate by loose ───────────────────────
     if not parts:
-        bpy.ops.wm.stl_import(filepath=stl_file)
-        obj = bpy.context.selected_objects[0] if bpy.context.selected_objects else None
-        if obj is None:
-            print(f"ERROR: No objects imported from {stl_file}")
+        print(f"ERROR: No mesh objects imported from {glb_file}")
         sys.exit(1)
 
-        bpy.context.view_layer.objects.active = obj
-        bpy.ops.object.origin_set(type='ORIGIN_GEOMETRY', center='BOUNDS')
-        obj.location = (0.0, 0.0, 0.0)
+    print(f"[turntable_render] imported {len(parts)} part(s) from GLB: "
+          f"{[p.name for p in parts[:5]]}")
 
-        bpy.ops.object.mode_set(mode='EDIT')
-        bpy.ops.mesh.separate(type='LOOSE')
-        bpy.ops.object.mode_set(mode='OBJECT')
-
-        parts = list(bpy.context.selected_objects)
-        print(f"[turntable_render] fallback: separated into {len(parts)} part(s)")
-        return parts
-
-    # ── Centre per-part imports at origin (combined bbox) ────────────────
+    # Centre combined bbox at world origin
     all_corners = []
     for p in parts:
         all_corners.extend(p.matrix_world @ Vector(c) for c in p.bound_box)
@@ -347,7 +281,7 @@ def main():
     # Everything after "--" is our args
     args = argv[argv.index("--") + 1:]
 
-    stl_path = args[0]
+    glb_path = args[0]
     frames_dir = args[1]
     frame_count = int(args[2])
     degrees = int(args[3])
@@ -427,10 +361,8 @@ def main():
         # Find or create target collection
         target_col = _ensure_collection(target_collection)
 
-        # Import and split STL
-        parts = _import_stl(stl_path)
-        # Scale mm→m: STEP coords are mm, Blender default unit is metres
-        _scale_mm_to_m(parts)
+        # Import OCC GLB (already in metres, one object per STEP part)
+        parts = _import_glb(glb_path)
         # Apply render position rotation before material/camera setup
         _apply_rotation(parts, rotation_x, rotation_y, rotation_z)
         # Apply OCC topology-based shading overrides
@@ -508,9 +440,7 @@ def main():
         needs_auto_camera = True
         bpy.ops.wm.read_factory_settings(use_empty=True)
 
-        parts = _import_stl(stl_path)
-        # Scale mm→m: STEP coords are mm, Blender default unit is metres
-        _scale_mm_to_m(parts)
+        parts = _import_glb(glb_path)
         # Apply render position rotation before material/camera setup
         _apply_rotation(parts, rotation_x, rotation_y, rotation_z)
         # Apply OCC topology-based shading overrides