Parallel Radiosity Using the Message Passing Interface

A method is described to parallelize the computation of global il- lumination using radiosity. Radiosity is a lighting technique which uses the diffuse properties of materials as well as emitting patches to determine the lighting in a closed space. By distributing light throughout a scene each iteration based on the properties of each surface, light is distributed until all light within a given threshold has been approximated. Radiosity is especially effective at render- ing effects such as color-bleeding(Goral et al. 1984). The tech- nique described in this paper parallelizes the initial setup of this method, calculating form factors, using the Message Passing Inter- face (MPI). We describe a method to distribute the work across pro- cessors as well as a number of optimizations to make our algorithm more efficient. Also described herein are the technical challenges faced as this algorithm was developed.