Importance and Discrete Three Point Transport

Global illumination within nondiffuse environments is ideally suited for computation under importance and radiance driven hierarchical refinement: a transport interaction is significant to the view from the eye only if it lies within paths of directional reflection of both radiance originating at a light source, and importance originating at the eye. We have recently developed a hierarchical algorithm for global illumination based on a radiance formulation for three point transport, and have implemented this algorithm over environments containing surfaces exhibiting glossy reflection. In this paper we derive the adjoint to our original transport formulation, and describe the preliminary results of application of this adjoint in the form of an importance driven version of our glossy implementation. These results show a significant reduction in transport computation, and indicate that an importance and radiance driven hierarchical technique possesses great promise for the development of efficient global illumination algorithms for general reflection. CR