1. Lapped Textures SIGGRAPH 2000 Emil Praun Adam Finkelstein Hugues Hoppe

2. Traditional Approach: Problems Not view independent Seams between multiple images Lack of user control over local orientation and scaling of texture

3. Lapped Textures: Definition Repeatedly pasting texture patches onto an arbitrary surface until completely covered

4. Goal No apparent seams No obvious periodicity Low distortion Local texture control Anisotropy

5. In other words … textured surface ?

6. Approach texture patch surface

7. The Patch Polygonal image region with alpha mask blending Generic pattern for many textures texture patch

8. Patch Pasting texture patch surfacesurface “lapped textures”

9. Algorithm - Outline Cut texture patches Specify direction and scale fields REPEAT Select random texture patch T Select random uncovered location L Grow surface patch S around L to size of T Flatten S over T Paste and update UNTIL mesh is covered

10. Process texture patch surface

11. Process texture patch surface

12. Process texture patch surface

13. Process texture patch surface

14. In Detail Texture patch creation Specifying direction field Surface patch growth Patch parametrization Texture storage and rendering

15. In Detail Texture patch creation Specifying direction field Surface patch growth Patch parametrization Texture storage and rendering

16. Texture Patch Creation Structured Splotch

17. In Detail Texture patch creation Specifying direction field Surface patch growth Patch parametrization Texture storage and rendering

18. Direction Field

19. In Detail Texture patch creation Specifying direction field Surface patch growth Patch parametrization Texture storage and rendering

20. Polygonal Hulls Start w/ boundary pixels, edges between neighbors Conservatively simplify polygons

21. Surface Patch Growth

28. In Detail Texture patch creation Specifying direction field Surface patch growth Patch parametrization Texture storage and rendering

29. Patch Alignment texture patch surface

30. Tangential Vector Basis

31. Optimizing the Parametrization TT SS BB CC AA (T)(T)(T)(T) (T)(T)(T)(T) (S)(S)(S)(S) (S)(S)(S)(S) (A)(A)(A)(A) (A)(A)(A)(A) (B)(B)(B)(B) (B)(B)(B)(B) (C)(C)(C)(C) (C)(C)(C)(C)  tt^^ss ^^ face in 3D 2D texture space

32. Optimizing the Parametrization Minimizing “Least Squares Functional”

33. In Detail Texture patch creation Specifying direction field Surface patch growth Patch parametrization Texture storage and rendering

34. Texture Storage and Rendering Texture Atlas –Pre-composite into a global texture map. Runtime pasting –Composite at run-time using hardware

35. Texture Atlas Patches of triangles with similar normals

36. Runtime Pasting Store vertex coordinates for each patch Composite at run-time using hardware May render triangles several times

37. Tradeoffs Atlas +Faster rendering, more portable –Sampling artifacts Pasting –Increases model complexity +Effective resolution +Reusability of splotch parameterizations

38. Examples: Splotches

39. Examples: Anisotropic

40. Controlling Direction and Scale

41. 25 frames per sec! 256 x 256 texture (282 times) 256 x 256 texture (282 times) 15,000 faces

42. Limitations low- frequency components boundarymismatch

43. Conclusions Effective texturing through:  Overlapping texture patche  Minimal edge blending Direction and scale Runtime pasting

44. Thank you