Introduces GMSH as an alternative to OCC BRepMesh for STEP→GLB tessellation.
GMSH produces conforming meshes that eliminate fan triangles at cylinder seam
edges — a structural limitation of OCC BRepMesh that cannot be fixed via
deflection parameters.
Changes:
- render-worker/Dockerfile: install gmsh>=4.15.0 + libglu1-mesa + libxft2
- export_step_to_gltf.py: --tessellation_engine occ|gmsh CLI arg +
_tessellate_with_gmsh() using BRep→GMSH→Poly_Triangulation write-back
- admin.py: tessellation_engine setting (SETTINGS_DEFAULTS, SettingsOut,
SettingsUpdate, validation)
- export_glb.py: pass tessellation_engine to export_step_to_gltf.py CLI in
both geometry and production GLB tasks
- Admin.tsx: radio button UI for OCC vs GMSH selection
Tested: 121 faces meshed, 0 BRepMesh fallback, 649K triangles on sample part.
Clean seam edges for UV unwrap — GMSH respects B-rep periodic face boundaries.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
When re-generating a production or geometry GLB, the old approach deleted the
existing MediaAsset record and created a new one with a new UUID. Any page that
had the old download_url (/api/media/{old-id}/download) cached would then get
a 404 when trying to download, because the asset ID no longer existed in the DB.
Fix: update the existing MediaAsset record in-place (same UUID, new storage_key)
so existing download URLs remain valid after regeneration. Create a new record
only if no existing one is found.
Applies to both generate_gltf_geometry_task and generate_gltf_production_task.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Hartmut