“Lightcuts: a scalable approach to illumination” by Walter, Fernandez, Arbree, Bala, Donikian, et al. …

Lightcuts is a scalable framework for computing realistic illumination. It handles arbitrary geometry, non-diffuse materials, and illumination from a wide variety of sources including point lights, area lights, HDR environment maps, sun/sky models, and indirect illumination. At its core is a new algorithm for accurately approximating illumination from many point lights with a strongly sublinear cost. We show how a group of lights can be cheaply approximated while bounding the maximum approximation error. A binary light tree and perceptual metric are then used to adaptively partition the lights into groups to control the error vs. cost tradeoff.We also introduce reconstruction cuts that exploit spatial coherence to accelerate the generation of anti-aliased images with complex illumination. Results are demonstrated for five complex scenes and show that lightcuts can accurately approximate hundreds of thousands of point lights using only a few hundred shadow rays. Reconstruction cuts can reduce the number of shadow rays to tens.

1. Agarwal, S., Ramamoorthi, R., Belongie, S., and Jensen, H. W. 2003. Structured importance sampling of environment maps. ACM Transactions on Graphics 22, 3 (July), 605–612. Google ScholarDigital Library
2. Blackwell, H. R. 1972. Luminance difference thresholds. In Handbook of Sensory Physiology, vol. VII/4: Visual Psychophysics. Springer-Verlag, 78–101.Google Scholar
3. Cohen-Or, D., Chrysanthou, Y. L., Silva, C. T., and Durand, F. 2003. A survey of visibility for walkthrough applications. IEEE Transactions on Visualization and Computer Graphics 9, 3, 412–431. Google ScholarDigital Library
4. Debevec, P. 1998. Rendering synthetic objects into real scenes: Bridging traditional and image-based graphics with global illumination and high dynamic range photography. In Proceedings of SIGGRAPH 98. Computer Graphics Proceedings, Annual Conference Series, 189–198. Google ScholarDigital Library
5. Fernandez, S., Bala, K., and Greenberg, D. P. 2002. Local illumination environments for direct lighting acceleration. In Rendering Techniques 2002: 13th Eurographics Workshop on Rendering, 7–14. Google ScholarDigital Library
6. Hanrahan, P., Salzman, D., and Aupperle, L. 1991. A rapid hierarchical radiosity algorithm. In Computer Graphics (Proceedings of SIGGRAPH 91), vol. 25, 197–206. Google ScholarDigital Library
7. Hasenfratz, J.-M., Lapierre, M., Holzschuch, N., and Sillion, F. 2003. A survey of real-time soft shadows algorithms. In Eurographics, Eurographics, Eurographics. State-of-the-Art Report.Google Scholar
8. Jensen, H. W. 2001. Realistic image synthesis using photon mapping. A. K. Peters, Ltd. Google ScholarDigital Library
9. Keller, A. 1997. Instant radiosity. In Proceedings of SIGGRAPH 97, Computer Graphics Proceedings, Annual Conference Series, 49–56. Google ScholarDigital Library
10. Kok, A. J. F., and Jansen, F. W. 1992. Adaptive sampling of area light sources in ray tracing including diffuse interreflection. Computer Graphics Forum (Eurographics ’92) 11, 3 (Sept.), 289–298.Google Scholar
11. Kollig, T., and Keller, A. 2003. Efficient illumination by high dynamic range images. In Eurographics Symposium on Rendering: 14th Eurographics Workshop on Rendering, 45–51. Google ScholarDigital Library
12. Křivánek, J., Gautron, P., Pattanaik, S., and Bouatouch, K. 2005. Radiance caching for efficient global illumination computation. IEEE Transactions on Visualization and Computer Graphics. Google ScholarDigital Library
13. Larson, G. J. W. 1992. Measuring and modeling anisotropic reflection. In Computer Graphics (Proceedings of SIGGRAPH 92), vol. 26, 265–272. Google ScholarDigital Library
14. Painter, J., and Sloan, K. 1989. Antialiased ray tracing by adaptive progressive refinement. In Computer Graphics (Proceedings of SIGGRAPH 89), vol. 23, 281–288. Google ScholarDigital Library
15. Paquette, E., Poulin, P., and Drettakis, G. 1998. A light hierarchy for fast rendering of scenes with many lights. Computer Graphics Forum 17, 3, 63–74.Google ScholarCross Ref
16. Phong, B. T. 1975. Illumination for computer generated pictures. Commun. ACM 18, 6, 311–317. Google ScholarDigital Library
17. Preetham, A. J., Shirley, P. S., and Smits, B. E. 1999. A practical analytic model for daylight. In Proceedings of SIGGRAPH 99, Computer Graphics Proceedings, Annual Conference Series, 91–100. Google ScholarDigital Library
18. Scheel, A., Stamminger, M., and Seidel, H.-P. 2001. Thrifty final gather for radiosity. In Rendering Techniques 2001: 12th Eurographics Workshop on Rendering, 1–12. Google ScholarDigital Library
19. Scheel, A., Stamminger, M., and Seidel, H. 2002. Grid based final gather for radiosity on complex clustered scenes. Computer Graphics Forum 21, 3, 547–556.Google ScholarCross Ref
20. Shirley, P., Wang, C., and Zimmerman, K. 1996. Monte carlo techniques for direct lighting calculations. ACM Transactions on Graphics 15, 1 (Jan.), 1–36. Google ScholarDigital Library
21. Sillion, F. X., and Puech, C. 1994. Radiosity and Global Illumination. Morgan Kaufmann Publishers Inc. Google ScholarDigital Library
22. Smits, B., Arvo, J., and Greenberg, D. 1994. A clustering algorithm for radiosity in complex environments. In Proceedings of SIGGRAPH 94, Annual Conference Series, 435–442. Google ScholarDigital Library
23. Tabellion, E., and Lamorlette, A. 2004. An approximate global illumination system for computer generated films. ACM Transactions on Graphics 23, 3 (Aug.), 469–476. Google ScholarDigital Library
24. Veach, E., and Guibas, L. J. 1997. Metropolis light transport. In Proceedings of SIGGRAPH 97, Computer Graphics Proceedings, Annual Conference Series, 65–76. Google ScholarDigital Library
25. Wald, I., Kollig, T., Benthin, C., Keller, A., and Slusallek, P. 2002. Interactive global illumination using fast ray tracing. In Rendering Techniques 2002: 13th Eurographics Workshop on Rendering, 15–24. Google ScholarDigital Library
26. Wald, I., Benthin, C., and Slusallek, P. 2003. Interactive global illumination in complex and highly occluded environments. In Eurographics Symposium on Rendering: 14th Eurographics Workshop on Rendering, 74–81. Google ScholarDigital Library
27. Walter, B., Alppay, G., Lafortune, E. P. F., Fernandez, S., and Greenberg, D. P. 1997. Fitting virtual lights for non-diffuse walk-throughs. In Proceedings of SIGGRAPH 97, Computer Graphics Proceedings, Annual Conference Series, 45–48. Google ScholarDigital Library
28. Walter, B. 2005. Notes on the Ward BRDF. Technical Report PCG-05-06, Cornell Program of Computer Graphics, Apr.Google Scholar
29. Ward, G. J., and Heckbert, P. 1992. Irradiance gradients. In Third Eurographics Workshop on Rendering, 85–98.Google Scholar
30. Ward, G. 1994. Adaptive shadow testing for ray tracing. In Photorealistic Rendering in Computer Graphics (Proceedings of the Second Eurographics Workshop on Rendering), Springer-Verlag, New York, 11–20.Google ScholarCross Ref
31. Woo, A., Poulin, P., and Fournier, A. 1990. A survey of shadow algorithms. IEEE Computer Graphics and Applications 10, 6 (Nov.), 13–32. Google ScholarDigital Library
32. Zaninetti, J., Boy, P., and Peroche, B. 1999. An adaptive method for area light sources and daylight in ray tracing. Computer Graphics Forum 18, 3 (Sept.), 139–150.Google ScholarCross Ref