Turning large CAD assemblies into real-time 3D visualizations- Unite Copenhagen 2019
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The document discusses the process of converting large CAD assemblies into real-time 3D visualizations using Pixyz software, focusing on the challenges and solutions associated with CAD data treatment. It details methods for optimizing geometry, mesh generation, and scene tree management to enhance visualization quality while maintaining performance. Key steps include CAD surface repair, tessellation, mesh optimization, and integration with platforms like Unity for immersive experiences.
Turning large CAD assemblies into real-time 3D visualizations- Unite Copenhagen 2019
- 2. Turning Large CAD Assemblies into Real-Time 3D Visualizations PiXYZ Software | Cédric Rousteau & Axel Jacquet
- 3. UNLOCK CAD DATA FOR REAL-TIME 3D EXPERIENCES First-class algorithms for automatic CAD/DCC data treatment What is PiXYZ? polygon model scan metadata nurbs data VR Training, Simulation, Product Viz, … AR Process Validation, product viz, marketing MOBILE Entertainment Marketing, Sales, Product Viz,… WEB Entertainment Marketing, Sales, Product Viz,… GAME & VFX Entertainment, Simulations, Visualization,… ANY DEVICE ANY USECASE
- 4. VRED to Unity workflow example LINK
- 5. Why is it a challenge to bring CAD assemblies in real-time 3D experiences? EXACT MATHEMATICAL GEOMETRIES BOUNDERY REPRESENTATIONS DESIGN PRODUCT STRUCTURE METADATA SIMPLIFIED HIERARCHY | ASSEMBLY OPTIMIZED MESH REAL-TIME ANIMATION PRODUCT MODELING INFORMATION PHYSICS PROPERTY MATERIALS LARGE ASSEMBLIES MATERIALS | UVs
- 6. • Many file formats CAD Import JT STEP IGES IFC
- 7. CAD Import • Complex and heavy product structure Root Rear Right Wheel Rear Left Wheel Rear Axle Right Wheel Left Wheel Axle Wheel Front Right Wheel Front Left Wheel Front Axle
- 8. • B-Rep Topology structure • 20 curve types • 22 surface types CAD Import
- 9. 1. Geometric optimization 2. Scene tree optimization 3. Meshes beautification 4. LODs Autodesk Alias to real-time 3D use case NURBS CAD Data
- 10. Alias Model Analysis Scene Tree • Hierarchy levels • Number of parts • Naming • Instances • Empty nodes • Variants • Pivot points BRep / Mesh Information Material Information Metadata
- 11. Geometric optimization Scene tree optimization Mesh beautification LOD
- 12. Step 1/11 Repairing CAD surfaces Inner free boundaries should be repaired (meaning stitched) prior to tessellation to create a beautiful, watertight mesh Repair CAD
- 13. Repair CAD algorithm • Sew face boundaries No CAD repair prior to tessellation = Gaps in the meshes
- 14. Repair CAD algorithm • Sew face boundaries • Remove duplicated faces No CAD repair prior to tessellation = non-manifold edges / duplicated polygons / Z-fighting
- 15. Repair CAD algorithm • Sew face boundaries • Remove duplicated faces • Optimize loops Without loop optimization With loop optimization
- 16. Step 2/11 Tessellation Generate mesh well balanced between quality and density 1 875 352 tris
- 17. Tessellation algorithm • Driven by criteria • Max Sag Sag = 0,1mm Sag = 0,2mm Radius=100mm Radius=50mm
- 18. Tessellation algorithm • Driven by criteria • Max Sag • Max Angle Angle = 10° Radius=100mm Radius=50mm Angle = 20°
- 19. Tessellation algorithm • Driven by criteria • Max Sag • Max Angle • Max Length Length = 10mm Radius=100mm Radius=50mm Length = 30mm ∞ 5 2 10
- 20. Tessellation algorithm • Driven by criteria (Sag, Angle, Length) • Based on fast and robust CAD modeler
- 21. Tessellation algorithm • Driven by criteria (Sag, Angle, Length) • Based on fast and robust CAD modeler • Alignment of vertices over surfaces Without alignment With alignment
- 23. Repair Mesh algorithm • Repair connectivity • Merge coincident vertices
- 24. Repair Mesh algorithm • Repair connectivity • Merge coincident vertices • Sew mesh boundaries
- 25. Repair Mesh algorithm • Repair connectivity • Merge coincident vertices • Sew mesh boundaries
- 26. Repair Mesh algorithm • Repair connectivity • Merge coincident vertices • Sew mesh boundaries • Orient consistently • Propagation
- 27. Repair Mesh algorithm • Repair connectivity • Merge coincident vertices • Sew mesh boundaries • Orient consistently • Propagation • Split Môbius strips
- 28. Step 4/11 Fix faces orientation
- 30. Smart Hidden Removal Remove hidden entities (parts, patches, polygons) using cavities automatic identification
- 31. Geometric optimization Scene tree optimization Mesh beautification LOD
- 32. Step 5/11 Optimize scene tree
- 33. Step 6/11 Adjust pivot points of moving parts
- 34. Geometric optimization Scene tree optimization Mesh beautification LOD
- 35. Step 7/11 Generate UVs & Assign material names
- 36. UV Generation • From CAD Faces • Surface parameterization • Uniform parameterization • By projection o Box o Spherical o Cylindrical • Automatic unwrap (beta) → Find the best lines to cut the mesh → Control angle and area deformation
- 37. Repack UV
- 38. Geometric optimization Scene tree optimization Mesh beautification LODs
- 39. Step 8/11 Export LOD 0 1 875 352 tris
- 40. Step 9/11 Decimate with quality control for LOD 1 1 875 352 tris 914 905 tris LOD0 LOD1
- 41. Decimation Algorithms • Quality driven o Vertex removal o Maximum deviation o Normal distorsion control o UV Distorsion control With normal control Without normal control
- 42. Decimation Algorithms • Polygon target o Edge collapse o Quadric Error Metric o Mesh attributes preserved 100 000 10 000 1 000
- 43. Step 10/11 Decimate with polygon target for LOD 2 148 494 tris
- 44. Step 11/11 Shadow & Physics proxy meshes 5 504 tris
- 45. Proxy Generation Proxy Mesh Voxelize Marching Cube
- 46. Baked Proxy Generation Baked PBR maps Original Model 40k triangles 3 materials 2 meshes Baked Model 8k triangles 1 material 1 mesh
- 47. Import in Unity… Mesh Metadata Product Structure Material Assignment via Rule Engine *.pxz file Credits: Unity Technologies
- 48. … and create great Real-time experiences Credits: Unity Technologies LINK
- 49. CAD DATA CATIA, SIEMENS NX, ALIAS, … MESH & 3D SCAN METADATA COLOR, MATERIAL, TEXTURE, NAME PLM DATA Data Prep automation
- 51. Thank you