1. Interactive Sampling and Rendering for Complex and Procedural Geometry
Marc Stamminger, George Drettakis
REVES/iMAGIS Sophia-Antipolis

2. motivation tree created by AMAP 150,000 triangles
8 fps (Linux PC with GeForce Quadro)

3. motivation rendered with points at 60 fps reduced quality
7 times faster

4. motivation
level of detail
100 trees
270,000 points
20 fps

5. previous work
1985 Levoy/Whitted "The Use of Points as a Display Primitive"
1998 Grossman/Dally "Point Sample Rendering"
2000 Rusinkiewicz/Levoy "The Q-Splat"
2000 Pfister/Zwicker/van Baar/Gross "Surfels"

6. very recent work Wand/Fischer/Peter/Meyer/auf der Heide/Strasser
"The Randomized z-Buffer Algorithm"

7. point rendering pipeline
scene description
vrml file
mgf file …
procedural model
point set
(3D-coordinates,
normal,
material)
screen
point rendering
point generation

8. point generation (orthographic) views filtered triangle mesh hierarchy
random points

9. point rendering in software in hardware filtering texturing
hole filling
in hardware
as points
as polygonal disks

10. our approach fast / on the fly point generation for procedural objects
terrains
complex dynamic objects
point rendering with OpenGL’s GL_POINT
very fast (up to 10 million points per second)
OpenGL does lighting

11. results
points are well suited for
procedural geometry

12. results
points are well suited for
procedural geometry
terrains

13. results points are well suited for procedural geometry terrains
complex geometry

14. results points are well suited for procedural geometry terrains
complex geometry
combinations

15. complex polygonal geometry
generate list of randomly distributed samples
for every frame: compute n, render the first n
100,000
10,000
1,000

16. complex polygonal geometry
easy speed / quality trade off
frame rate control
100,000
10,000
1,000

17. modified complex geometry
simple modifications on the fly
30 fps

18. displaced geometry
25,000 points
25,000 points

19. displaced geometry
25,000 points
100,000 points

20. adaptive sampling

21. undersampling factor
< 1
> 1

22. undersampling factor

23. video sqrt(5) sampling

24. adaptive point generation

25. sqrt(5) sampling
(2/5,1/5)

26. sqrt(5) sampling

27. sqrt(5) sampling

28. sqrt(5) sampling

29. sqrt(5) sampling

30. sqrt(5) sampling

31. sqrt(5) sampling rotated, nested grids special attention to boundaries
grid distance decreases by 1/sqrt(5)
rotation angle  27o
special attention to boundaries

32. procedural modifiers

33. terrains

34. terrains

35. terrain parameterization
parameterize by (d,u) d u
terrain d u
screen

36. terrain parameterization
looking straight ahead
looking up
looking down

37. terrain algorithm sqrt(5) sampling scheme undersampling factor
parameterization distortions
perspective distortions
displacement

38. terrain occlusion culling
regular sampling
occlusion culling,
with adaptive sampling

39. video results

40. conclusion
points are very powerful, when details become smaller than a pixel
simple and efficient level of detail
simple manipulation
easily parallelizable
big potential for further improvements

41. link
more at:

42. with a Marie-Curie fellowship
acknowledgements
thanks to the European Union for funding me
with a Marie-Curie fellowship