Realism in Real Time?

With the continuous improvement in ray tracing and radiosity algorithms, image synthesis quality has reached the level of photo realism. However, efforts to achieve real-time performances by implementing ray tracing and radiosity algorithms on parallel processors and dedicated hardware have not been very successful so far. Increasing the number of processors introduces a corresponding growth in inter-processor communication. Caching could be effective to reduce communication, if sufficient coherence would be available in subsequent data requests. Unfortunately, standard ray tracing and radiosity do not provide enough coherence. In this paper we review the different parallel approaches and we try to ascertain those issues that are crucial for further improvement. In particular, we will focus on load and data management strategies that effect the amount of data coherence in ray tracing, and on methods to improve ray and object coherence.