  The Parallel Virtual Machine (PVM) tool has been used for a distributed
implementation of Greg Ward's Radiance code. In order to generate exactly the
same primary rays with both the sequential and the parallel codes, the quincunx
sampling technique used in Radiance for the reduction of the number of primary
rays by interpolation, must be left untouched in the parallel implementation.
The octree of local ambient values used in Radiance for the indirect
illumination has been shared among all the processors. Both static and dynamic
image partitioning techniques which replicate the octree of the complete scene
in all the processors and have load-balancing, have been developed for one
frame rendering. Speedups larger than 7.5 have been achieved in a network of 8
workstations. For animation sequences, a new dynamic partitioning distribution
technique with superlinear speedups has also been developed.
