Precomputed Radiance Transfer

This paper describes a method for rendering interreflections, self-induced shadows and caustics in real-time in a general low-frequency lighting environment. The method handles environment and area lighting and glossy as well as diffuse objects. The lighting environment is projected onto a lowfrequency spherical harmonic basis. Before the rendering a transfer vector (diffuse case) or a transfer matrix table is created for the object through preprocessing. This table takes into account the object’s interreflections and self occlusions and is used with the spherical harmonic lighting components to evaluate the total exiting radiance of each visible vertex of the object.