DIRmaps : Discretized Incident Radiance Maps for High-Quality Global Illumination Walkthroughs in Complex Environments

Realtime ray tracing and interactive global illumination have recently made significant progress, allowing for ray traced rendering quality even in highly complex scenes. Nevertheless, high-quality global illumination is currently still limited to offline computations, as existing interactive techniques are applicable only to simple scenes, BRDFs, and/or lighting conditions. For realistically complex scenes, BRDFs, and lighting situations existing systems still have to compromise either performance or image quality, even if considerable compute power is invested. In this paper, we present a method that uses a precomputation approach to obtain a high-quality solution of the global illumination that is then used during interactive rendering. This solution is stored in a directionally dependent way, thus supporting complex BRDFs such as glossy surfaces or BTFs. Additionally, the illumination is stored independent of geometry, allowing for supporting arbitrary kinds of surface primitives as well as highly complex models. Using our method in a distributed interactive ray tracing system, we achieve interactive performance even for highly complex geometry, complex BRDFs and BTFs, and highly complex lighting situations, while maintaining offline-comparable image quality. SCI Institute, University of Utah Technical Report UUSCI-2005-010 DIRmaps : Discretized Incident Radiance Maps for High-Quality Global Illumination Walkthroughs in Complex Environments Ingo Wald SCI Institute, University of Utah, UT, 84112