Parallel volume rendering and data coherence

The two key issues in implementing a parallel ray-casting volume renderer are the work distribution and the data distribution. We have implemented such a renderer on the Fujitsu AP1000 using an adaptive image-space subdivision algorithm based on the worker-farm paradigm for the work distribution, and a distributed virtual memory, implemented in software, to provide the data distribution. Measurements show that this scheme works efficiently and effectively utilizes the data coherence that is inherent in volume data.