Virtual Spherical Lights for Many-Light Rendering of Glossy Scenes

Milos Hasan, Jaroslav Krivanek, Bruce Walter, Kavita Bala

Proceedings of SIGGRAPH Asia 2009



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Abstract: In this paper, we aim to lift the accuracy limitations of many- light algorithms by introducing a new light type, the virtual spher- ical light (VSL). The illumination contribution of a VSL is com- puted over a non-zero solid angle, thus eliminating the illumination spikes that virtual point lights used in traditional many-light meth- ods are notorious for. The VSL enables application of many-light approaches in scenes with glossy materials and complex illumina- tion that could previously be rendered only by much slower algo- rithms. By combining VSLs with the matrix row-column sampling algorithm, we achieve high-quality images in one to four minutes, even in scenes where path tracing or photon mapping take hours to converge.