ABSTRACT
Radiance transfer represents how generic source lighting is shadowed and scattered by an object to produce view-dependent appearance. We generalize by rendering transfer at two scales. A macro-scale is coarsely sampled over an object's surface, providing global effects like shadows cast from an arm onto a body. A meso-scale is finely sampled over a small patch to provide local texture. Low-order (25D) spherical harmonics represent low-frequency lighting dependence for both scales. To render, a coefficient vector representing distant source lighting is first transformed at the macro-scale by a matrix at each vertex of a coarse mesh. The resulting vectors represent a spatially-varying hemisphere of lighting incident to the meso-scale. A 4D function, called a radiance transfer texture (RTT), then specifies the surface's meso-scale response to each lighting basis component, as a function of a spatial index and a view direction. Finally, a 25D dot product of the macro-scale result vector with the vector looked up from the RTT performs the correct shading integral. We use an id map to place RTT samples from a small patch over the entire object; only two scalars are specified at high spatial resolution. Results show that bi-scale decomposition makes preprocessing practical and efficiently renders self-shadowing and interreflection effects from dynamic, low-frequency light sources at both scales.
Supplemental Material
- ASHIKHMIN, M, AND SHIRLEY, P, Steerable Illumination Textures, ACM Transactions on Graphics, 2(3), 2002. Google ScholarDigital Library
- DANA, K, VAN GINNEKEN, B, NAYAR, S, AND KOENDERINK, J, Reflectance and Texture of Real World Surfaces, ACM Transactions on Graphics, 1999, 18(1):1--34. Google ScholarDigital Library
- DAUBERT, K, LENSCH, H, HEIDRICH, W, SEIDEL, H, Efficient Cloth Modeling and Rendering, EG Rendering Workshop 2001. Google ScholarDigital Library
- HEIDRICH, W, DAUBERT, K, KAUTZ, J, AND SEIDEL, H, Illuminating Micro Geometry based on Precomputed Visibility, SIGGRAPH 2000, 455--464. Google ScholarDigital Library
- KAJIYA, J, Anisotropic Reflection Models, SIGGRAPH 1985, 15--21. Google ScholarDigital Library
- KAUTZ, J, SLOAN, P, AND SNYDER J, Fast, Arbitrary BRDF Shading for Low-Frequency Lighting Using Spherical Harmonics, Eurographics Workshop on Rendering 2002, 291--296. Google ScholarDigital Library
- LIU, X, YU, Y, AND SHUM, H, Synthesizing Bidirectional Texture Functions for Real-World Surfaces, SIGGRAPH 2001, 97--106. Google ScholarDigital Library
- LIU, X, HU, Y, ZHANG, J, TONG, X, GUO, B, AND SHUM, H, Synthesis and Rendering of Bidirectional Texture Functions on Arbitrary Surfaces, submitted for publication to IEEE TVCG, Nov, 2002. Google ScholarDigital Library
- MALZBENDER, T, GELB, D, AND WOLTERS, H, Polynomial Texture Maps, SIGGRAPH 2001, 519--528. Google ScholarDigital Library
- MCALLISTER, D, LASTRA, A, AND HEIDRICH, W, Efficient Rendering of Spatial Bi-directional Reflectance Distribution Functions, Graphics Hardware 2002. Google ScholarDigital Library
- MOUNT, D, ANN Programming Manual, Dept. Comp. Sci., Univ. of Maryland, College Park, Maryland, 1998. http://www.cs.umd.edu/~mount/ANN/Google Scholar
- SANDER, P, SNYDER, J, GORTLER, S, AND HOPPE, H, Texture Mapping Progressive Meshes, SIGGRAPH 2001, 409--416. Google ScholarDigital Library
- SHIRLEY, P, AND CHIU, K, A Low Distortion Map between Disk and Square, Journal of Graphics Tools, vol. 2, no. 3, 1997, 45--52. Google ScholarDigital Library
- SLOAN, P., KAUTZ, J, AND SNYDER J, Precomputed Radiance Transfer for Real-Time Rendering in Dynamic, Low-Frequency Lighting Environments, SIGGRAPH 2002, 527--536. Google ScholarDigital Library
- TONG, X, ZHANG, J, LIU, L, WANG, X, GUO, B, AND SHUM, H, Synthesis of Bidirectional Texture Functions on Arbitrary Surfaces, SIGGRAPH 2002, 665--672. Google ScholarDigital Library
- TURK, G, Texture Synthesis on Surfaces, SIGGRAPH 2001, 347--354. Google ScholarDigital Library
Recommendations
Bi-scale radiance transfer
Radiance transfer represents how generic source lighting is shadowed and scattered by an object to produce view-dependent appearance. We generalize by rendering transfer at two scales. A macro-scale is coarsely sampled over an object's surface, ...
Precomputed radiance transfer for real-time rendering in dynamic, low-frequency lighting environments
We present a new, real-time method for rendering diffuse and glossy objects in low-frequency lighting environments that captures soft shadows, interreflections, and caustics. As a preprocess, a novel global transport simulator creates functions over the ...
Precomputed radiance transfer for real-time rendering in dynamic, low-frequency lighting environments
SIGGRAPH '02: Proceedings of the 29th annual conference on Computer graphics and interactive techniquesWe present a new, real-time method for rendering diffuse and glossy objects in low-frequency lighting environments that captures soft shadows, interreflections, and caustics. As a preprocess, a novel global transport simulator creates functions over the ...
Comments