“Practical filtering for efficient ray-traced directional occlusion”
Conference:
Type(s):
Title:
- Practical filtering for efficient ray-traced directional occlusion
Session/Category Title: Light Transport
Presenter(s)/Author(s):
Abstract:
Ambient occlusion and directional (spherical harmonic) occlusion have become a staple of production rendering because they capture many visually important qualities of global illumination while being reusable across multiple artistic lighting iterations. However, ray-traced solutions for hemispherical occlusion require many rays per shading point (typically 256-1024) due to the full hemispherical angular domain. Moreover, each ray can be expensive in scenes with moderate to high geometric complexity. However, many nearby rays sample similar areas, and the final occlusion result is often low frequency. We give a frequency analysis of shadow light fields using distant illumination with a general BRDF and normal mapping, allowing us to share ray information even among complex receivers. We also present a new rotationally-invariant filter that easily handles samples spread over a large angular domain. Our method can deliver 4x speed up for scenes that are computationally bound by ray tracing costs.
References:
1. AcademyAwards, 2010. Scientific and Technical Achievements to be Honored with Academy Awards. http://www.oscars.org/press/pressreleases/2010/20100107.html.Google Scholar
2. Arikan, O., Forsyth, D. A., and O’Brien, J. F. 2005. Fast and Detailed Approximate Global Illumination by Irradiance Decomposition. ACM Trans. on Graph. (SIGGRAPH) 24, 1108–1114. Google ScholarDigital Library
3. Bavoil, L., and Sainz, M. 2009. ShaderX7 – Advanced Rendering Techniques. ch. Image-Space Horizon-Based Ambient Occlusion.Google Scholar
4. Chai, J., Tong, X., Chan, S., and Shum, H. 2000. Plenoptic Sampling. In Proceedings of SIGGRAPH 2000, 307–318. Google ScholarDigital Library
5. Christensen, P. H. 2008. Point-Based Approximate Color Bleeding. Tech. Rep. 08–01, Pixar Animation Studios.Google Scholar
6. Durand, F., Holzschuch, N., Soler, C., Chan, E., and Sillion, F. X. 2005. A Frequency Analysis of Light Transport. ACM Transactions on Graphics (SIGGRAPH 05) 24, 3, 1115–1126. Google ScholarDigital Library
7. Egan, K., Tseng, Y.-T., Holzschuch, N., Durand, F., and Ramamoorthi, R. 2009. Frequency Analysis and Sheared Reconstruction for Rendering Motion Blur. ACM Trans. on Grap. (SIGGRAPH) 28, 3, 93:1–93:13. Google ScholarDigital Library
8. Egan, K., Hecht, F., Durand, F., and Ramamoorthi, R. 2011. Frequency Analysis and Sheared Filtering for Shadow Light Fields of Complex Occluders. ACM Trans. on Graph. 30, 2, 9:1–9:13. Google ScholarDigital Library
9. Hašan, M., Pellacini, F., and Bala, K. 2007. Matrix row-column sampling for the many-light problem. ACM Trans. Graph. 26, 3, 26:1–26:10. Google ScholarDigital Library
10. Huang, F.-C., and Ramamoorthi, R. 2010. Sparsely Precomputing the Light Transport Matrix for Real-Time Rendering. Computer Graphics Forum (EGSR 10) 29, 4. Google ScholarDigital Library
11. Křivánek, J., Gautron, P., Pattanaik, S., and Bouatouch, K. 2005. Radiance caching for efficient global illumination computation. IEEE Trans. on Visualization and Computer Graphics 11, 5. Google ScholarDigital Library
12. Laine, S., and Karras, T. 2010. Two methods for fast ray-cast ambient occlusion. Computer Graphics Forum (EGSR 10) 29, 4. Google ScholarDigital Library
13. Landis, H. 2008. Production ready global illumination. In ACM SIGGRAPH Course Notes: RenderMan in Production, 87–102.Google Scholar
14. Lanman, D., Raskar, R., Agrawal, A., and Taubin, G. 2008. Shield Fields: Modeling and Capturing 3D Occluders. ACM Transactions on Graphics (SIGGRAPH Asia) 27, 5. Google ScholarDigital Library
15. Lehtinen, J., Aila, T., Chen, J., Laine, S., and Durand, F. 2011. Temporal Light Field Reconstruction for Rendering Distribution effects. ACM Trans. Graph. 30, 4. Google ScholarDigital Library
16. McGuire, M. 2010. Ambient Occlusion Volumes. In Proceedings of High Performance Graphics 2010, 47–56. Google ScholarDigital Library
17. Méndez-Feliu, A., and Sbert, M. 2009. From Obscurances to Ambient Occlusion: A Survey. Vis. Comput. 25, 2, 181–196. Google ScholarDigital Library
18. Ng, R., Ramamoorthi, R., and Hanrahan, P. 2003. All-Frequency Shadows Using Non-Linear Wavelet Lighting Approximation. ACM Trans. on Graph. (SIGGRAPH 03) 22, 3, 376–381. Google ScholarDigital Library
19. Pantaleoni, J., Fascione, L., Hill, M., and Aila, T. 2010. PantaRay: Fast Ray-Traced Occlusion Caching of Massive Scenes. ACM Trans. on Graph. (SIGGRAPH 10) 29, 4, 37:1–37:10. Google ScholarDigital Library
20. Pixar, 2005. The RenderMan Interface, version 3.2.1. https://renderman.pixar.com/products/rispec/rispec_pdf/RISpec3_2.pdf.Google Scholar
21. Ramamoorthi, R., Koudelka, M., and Belhumeur, P. 2005. A fourier theory for cast shadows. IEEE Trans. Pattern Anal. Mach. Intell. 27, 2, 288–295. Google ScholarDigital Library
22. Shinya, M. 1993. Spatial anti-aliasing for animation sequences with spatio-temporal filtering. In SIGGRAPH ’93, 289–296. Google ScholarDigital Library
23. Sloan, P., Kautz, J., and Snyder, J. 2002. Precomputed radiance transfer for real-time rendering in dynamic, low-frequency lighting environments. ACM TOG (SIGGRAPH 02) 21, 3. Google ScholarDigital Library
24. Soler, C., and Sillion, F. 1998. Fast Calculation of Soft Shadow Textures Using Convolution. In Proceedings of SIGGRAPH 98, ACM Press/ACM SIGGRAPH, 321–332. Google ScholarDigital Library
25. Ward, G., Rubinstein, F., and Clear, R. 1988. A Ray Tracing Solution for Diffuse Interreflection. In SIGGRAPH 88, 85–92. Google ScholarDigital Library
26. Zhukov, S., Iones, A., and Kronin, G. 1998. An ambient light illumination model. In Rendering Techniques (Eurographics 98), 45–56.Google Scholar
