"Powerful GPU techniques for next generation visualization engines” spring 2010

1. "Powerful GPU techniques for next generation visualization engines”spring 2010 Henrik Lieng Tomas Osland Tobias Lie Andersen.

2. Sf Constructor - Interactive visualization of CAD data

3. Bachelor Description - "Powerful GPU techniques for next generation visualization engines"

4. SURFACE RECONSTRUCTION FOR INDUSTRIAL POINT CLOUDS

5. Raw LASER SCAN DATA Laser scanners produce point clouds

6. OUTLIER REMOVAL Use standard deviation to trim the point set.

7. simplification Consider our world as a grid. Each cell in this grid can only contain one point

8. Simplification - RESULTS

9. DELAUNAY BASED SURFACE RECONSTRUCTION USING SCALAR FIELDS • Some key concepts: • Convex and concave set: convex set concave set property of: Wikipedia

10. Key consepts • Convex hull • Scalar field • Voxel

11. Delaunay 3D triangulation • A polygon is valid if its circumscribed sphere is empty • Figure taken from cgal.org

12. Delaunay and concave sets • Delaunay triangulation is a projection of a convex hull

13. Delaunay and a 3D concave set

14. Refine triangulation using a scalar field

15. Result

16. Comparison with other methods Ball Pivoting • Our method

17. Comparison with other methods Ball Pivoting • Our method

18. Project assessment • Initial milestone plan

19. Rasterization with ray traced specular maps

20. Rasterization with ray traced specular maps

21. Ray-tracing Principles of Ray tracing: We cast a ray for every point on the screen. What this point will show depends on what the ray hits.

22. OPTIX realtime ray-tracer

23. Optix realtime ray-tracer • Ray tracing engine with extreme performance. • Take advantage of the multi-thread capabilities of graphics cards. • Programming language: Cuda (like C) CUDA SceniX

24. Sub tasks Create a scene that uses Optix shaders Create a Optix Program with reflections Create a Optix Program that creates a specular reflection map

25. Simple scene rendered by OpenGL

26. Simple scene rendered by Optix

27. Specular Reflection Map

28. Sub tasks (part 2) Create the reflections without rendering the scene to the screen. Obtain the specular reflection map from the Optix shader Render scene with both rasterization and ray tracing.

29. Original 3D model - OpenGL

30. Specular Reflection Map

31. Final result – OpenGL + Reflections

32. Optimization • Two limits: • How far rays can travel • How far from the eye reflections can be made

33. Optimization Optimized: 26% performance improvement Original

34. Project assessment • Good looking results • Optimization gave a performance boost • The two renderings can be better merged

35. GPU driven procedural light sprites

36. Milestones Set up environment OpenGL light sprites SceniX light sprites with models Procedural light sprites with Cg shader

37. model without effects

38. Loading positions intFileLoader::loadCoordinates( const std::string &filename, std::vector< nvmath::Vec3f > &coords) { std::ifstreaminstream; intnumVecs = 0; intnumElm = 0; float x, y, z, input; instream.open(filename.c_str()); while(instream >> input) { if(numElm % 3 == 0) { z = input; } else if(numElm % 3 == 1) { x = input; } else if(numElm % 3 == 2) { y = input; numVecs++; coords.push_back( nvmath::Vec3f( x, y - 15.0, z) ); } numElm++; } return numVecs; }

39. Light texture in model

40. Billboard in model

41. texture billboard in model

42. Vertex shader VertexOutputVertexMain(float4 position: POSITION, float4 color: COLOR, uniform float4x4 modelviewproj) { VertexOutput OUT; float n = 0.0; n = noise(position.xy) + 2.0 * 0.4; OUT.position = mul(modelviewproj, position); OUT.texcoord = position; OUT.color = color * (n / 4.0); return OUT; }

43. Fragment shader FragmentOutputFragmentMain(float4 color: COLOR, VertexOutput IN) { FragmentOutput OUT; float n = 1.0; if(IN.texcoord.y > 0.0) { n *= (100.0 - IN.texcoord.y) / 100.0; } else if(IN.texcoord.y < 0.0) { n *= (100.0 + IN.texcoord.y) / 100.0; } if(IN.texcoord.x < 0.0) { n *= (450.0 + IN.texcoord.x) / 100.0; } else if(IN.texcoord.x > 0.0) { n *= (450.0 - IN.texcoord.x) / 100.0; } OUT.color = color * n; return OUT; }

44. procedural texture in model

45. Project assessment The assignment were completed according to Stormfjords requirements. Efficiency boost using procedural textures. Image texture 53.0 fps Procedural texture 59.9 fps Some downsides Light data must be found manually Two procedural shaders are used

46. Overall Conclusion A difficult but educational project Much research Good planning on all parts of the assignment Employer expressed satisfaction with our work