Photo-realistic computergraphics is an area of research which tries to develop algorithms and methods to render images of arti cial models or worlds as realistically as possible, by carrying out lighting simulations. Such algorithms are known for their unpredictable data accesses and their high computational complexity. Rendering a single high quality image may take several hours, or even days. For this reason parallel processing must be considered as a viable option to compute images in a reasonable time. The nature of data access patterns and often the sheer size of the scene to be rendered, means that a straightforward parallelisation, if one exists, may not always lead to good performance. This paper discusses a suitable parallelisation of an advanced ray tracing algorithm using PVM, and presents a method of reducing the number of messages required for data and task communication by bundling a number of tasks or data items into a single message.