“Local, deformable precomputed radiance transfer” by Sloan, Luna and Snyder

Precomputed radiance transfer (PRT) captures realistic lighting effects from distant, low-frequency environmental lighting but has been limited to static models or precomputed sequences. We focus on PRT for local effects such as bumps, wrinkles, or other detailed features, but extend it to arbitrarily deformable models. Our approach applies zonal harmonics (ZH) which approximate spherical functions as sums of circularly symmetric Legendre polynomials around different axes. By spatially varying both the axes and coefficients of these basis functions, we can fit to spatially varying transfer signals. Compared to the spherical harmonic (SH) basis, the ZH basis yields a more compact approximation. More important, it can be trivially rotated whereas SH rotation is expensive and unsuited for dense per-vertex or per-pixel evaluation. This property allows, for the first time, PRT to be mapped onto deforming models which re-orient the local coordinate frame. We generate ZH transfer models by fitting to PRT signals simulated on meshes or simple parametric models for thin membranes and wrinkles. We show how shading with ZH transfer can be significantly accelerated by specializing to a given lighting environment. Finally, we demonstrate real-time rendering results with soft shadows, inter-reflections, and subsurface scatter on deforming models.

1. Ashikhmin, M., and Shirley, P. 2002. Steerable illumination textures. ACM Trans. Gr. 2, 3. Google ScholarDigital Library
2. Choi, C., Ivanic, J., Gordon, M., and Ruedenberg, K. 1999. Rapid and stable determination of rotation matrices between spherical harmonics by direct recursion. The Journal of Chemical Physics 111, 19 (November), 8825–8831.Google ScholarCross Ref
3. Cook, R., and Torrance, K. 1982. A reflectance model for computer graphics. ACM Trans. Gr. 1, 1, 7–24. Google ScholarDigital Library
4. Dana, K., Nayar, S., Van Ginneken, B., and Koenderink, J. 1999. Reflectance and texture of real-world surfaces. ACM TOG 18, 1–34. Google ScholarDigital Library
5. Driscoll, J., and Healy, D. 1994. Computing fourier transforms and convolutions on the 2-sphere. Adv. in Appl. Math. 15, 202–250. Google ScholarDigital Library
6. Fernando, R. 2004. GPU Gems: Programming Techniques. Tips, and Tricks for Real-Time Graphics. Addison-Weseley Professional. Google ScholarDigital Library
7. Heidrich, W., Daubert, K., Kautz, J., and Seidel, H. 2000. Illuminating micro-geometry based on precomputed visibility. In Proc. SIGGRAPH ’00, 455–464. Google ScholarDigital Library
8. James, D., and Fatahalian, K. 2003. Precomputing interactive dynamic deformable scenes. In Proc. of SIGGRAPH ’03, 879–887. Google ScholarDigital Library
9. Kaneko, T., Takahei, T., Inami, M., Kawakami, M., Yanagida, Y., Maeda, T., and Tachi, S. 2001. Detailed shape representation with parallax mapping. In Proc. of ICAT 2001, 205–208.Google Scholar
10. Kautz, J., Sloan, P., and Snyder, J. 2002. Fast, arbitrary brdf shading for low-frequency lighting using spherical harmonics. Eurographics Workshop on Rendering, 291–296. Google ScholarDigital Library
11. Kautz, J., Lehtinen, J., and Aila, T. 2004. Hemispherical rasterization for self-shadowing of dynamic objects. Proceedings Eurographics Symposium on Rendering, 179–184. Google ScholarDigital Library
12. Lafortune, E., Foo, S., Torrance, K., and Greenberg, D. 1997. Nonlinear approximation of reflectance functions. In Proc. of SIGGRAPH ’97, 117–126. Google ScholarDigital Library
13. Lensch, H., Kautz, J., Goesele, M., Heidrich, W., and Seidel, H. 2001. Image-based reconstruction of spatially-varying materials. In EG Rendering Workshop, 103–114. Google ScholarDigital Library
14. Liu, X., Sloan, P., Shum, H., and Snyder, J. 2004. All-frequency precomputed radiance transfer for glossy objects. In Proc. of 2004 Eurographics Symposium on Rendering. Google ScholarDigital Library
15. Malzbender, T., Gelb, D., and Wolters, H. 2001. Polynomial texture maps. In Proc. of SIGGRAPH ’01, 519–528. Google ScholarDigital Library
16. Max, N. 1988. Horizon mapping: shadows for bump-mapped surfaces. The Visual Computer 4, 2, 109–117.Google ScholarCross Ref
17. McCallister, D., Lastra, A., and Heidrich, W. 2002. Efficient rendering of spatial bidirectional reflectance distribution functions. In Graphics Hardware ’02, 171–178. Google ScholarDigital Library
18. Meyer, A., and Neyret, F. 1998. Interactive volumetric textures. In Eurographics Workshop on Rendering, 157–168.Google Scholar
19. Miller, G. 1994. Efficient algorithms for local and global accessibility shading. In Proc. of SIGGRAPH ’94, 319–326. Google ScholarDigital Library
20. Muller, G., Meseth, J., and Klein, R. 2004. Fast environmental lighting for local-pca encoded btfs. In Proc. of Computer Graphics International, 198–205. Google ScholarDigital Library
21. Ng, R., Ramamoorthi, R., and Hanrahan, P. 2003. All-frequency shadows using non-linear wavelet lighting approximation. In Proc. of SIGGRAPH ’03, 376–381. Google ScholarDigital Library
22. Nocedal, J., and Wright, S. 1999. Numerical Optimization. Springer-Verlag.Google Scholar
23. Oliveira, M., Bishop, G., and McCallister, D. 2000. Relief texture mapping. In Proc. of SIGGRAPH ’00, 359–368. Google ScholarDigital Library
24. Press, W., Teukolsky, S., Vetterling, W., and Flannery, B. 1992. Numerical Recipes in C. Second Edition. Cambridge University Press, Cambridge, England. Google ScholarDigital Library
25. Ramamoorthi, R., and Hanrahan, P. 2001. An efficient representation for irradiance environment maps. In Proc. of SIGGRAPH ’01, 497–500. Google ScholarDigital Library
26. Shirley, P., and Chiu, K. 1997. A low distortion map between disk and square. Journal of Graphics Tools 2, 3, 45–52. Google ScholarDigital Library
27. Sloan, P., Kautz, J., and Snyder, J. 2002. Precomputed radiance transfer for real-time rendering in dynamic, low-frequency lighting environments. In Proc. of SIGGRAPH ’02, 527–536. Google ScholarDigital Library
28. Sloan, P., Hall, J., Hart, J., and Snyder, J. 2003. Clustered principal components for precomputed radiance transfer. In Proc. of SIGGRAPH ’03, 382–391. Google ScholarDigital Library
29. Sloan, P., Liu, X., Shum, H., and Snyder, J. 2003. Bi-scale radiance transfer. In Proc. of SIGGRAPH ’03, 370–375. Google ScholarDigital Library
30. Wang, L., Wang, X., Tong, X., Lin, S., Hu, S., Guo, B., and Shum, H. 2003. View-dependent displacement mapping. In Proc. of SIGGRAPH ’03, 334–339. Google ScholarDigital Library
31. Wang, R., Tran, J., and Luebke, D. 2004. All-frequency relighting of non-diffuse objects using separable brdf approximation. In Proc. of 2004 Eurographics Symposium on Rendering. Google ScholarDigital Library
32. Westin, S., Arvo, J., and Torrance, K. 1992. Predicting reflectance functions from complex surfaces. In Proc. of SIGGRAPH ’92, 255–272. Google ScholarDigital Library
33. Whittaker, E., and Watson, G. 1990. A Course in Modern Analysis, 4th Ed. Cambridge University Press, Cambridge, England.Google Scholar