Radiance is a software package developed at Lawrence Berkeley National Laboratory for lighting visualization. Lighting visualization predicts how lighting would appear if a modelled scene were to be physically realized. Unlike most lighting systems, Radiance physically models the effects of lighting, providing an image that is closer to physical reality. This is of obvious benefit to architects and lighting designers. Such visualizations are computationally expensive: rendering a single image can take hours on a standard workstation environment. Ideally, an architect would like to be able to interactively navigate through a scene to get a full impression of the true appearance of a particular model. With this goal in mind, we have (1) developed a geometric-based method (point cloud) to reuse pixels from a previous frame and (2) developed a parallel, distributed memory implementation of Radiance and the point cloud using MPI for inter-processor communication.