Modular Radiance Transfer

Bradford J. Loos, Lakulish Antani, Kenny Mitchell, Derek Nowrouzezahrai, Wojciech Jarosz, Peter-Pike Sloan
2011 Proceedings of the 2011 SIGGRAPH Asia Conference on - SA '11  
Figure 1 : Indirect light computed in reduced subspaces for a cave with 19 blocks and 4 lights. We derive low-dimensional transport operators, on simple proxy shapes, that are warped and combined at run-time, at > 475 FPS on high-end GPUs and > 45 FPS on mobile platforms, and can model indirect light at surfaces (with detailed normal variation) and within volumes of large-scale scene geometry. Abstract Many rendering algorithms willingly sacrifice accuracy, favoring plausible shading with
more » ... erformance. Modular Radiance Transfer (MRT) models coarse-scale, distant indirect lighting effects in scene geometry that scales from high-end GPUs to low-end mobile platforms. MRT eliminates scene-dependent precomputation by storing compact transport on simple shapes, akin to bounce cards used in film production. These shapes' modular transport can be instanced, warped and connected on-the-fly to yield approximate light transport in large scenes. We introduce a prior on incident lighting distributions and perform all computations in low-dimensional subspaces. An implicit lighting environment induced from the low-rank approximations is in turn used to model secondary effects, such as volumetric transport variation, higher-order irradiance, and transport through lightfields. MRT is a new approach to precomputed lighting that uses a novel low-dimensional subspace simulation of light transport to uniquely balance the need for high-performance and portable solutions, low memory usage, and fast authoring iteration.
doi:10.1145/2070752.2024212 fatcat:xa75chzyvrbvzdxriei3ppjt4u