Exact radiosity reconstruction and shadow computation using vertex tracing (original) (raw)

Methods for exact computation of irradiance and form factors associated with polygonal objects have ultimately relied on a formula for a differential area to polygon form factor attributed to Lambert. This paper introduces an alternative to Lambert's formula, an analytical expression which independent of the vertex order of the polygon. In this formulation, irradiance values in a scene consisting of partially occluded uniformly emitting polygons can be computed exactly by examining only the set of apparent vertices visible from the point of evaluation, where no vertex ordering is required. The method is particularly applicable to radiosity reconstruction, in which all the scene polygons are diffuse emitters, and also in environments where efficiency structures have already been established.