This project focuses on techniques for photorealistic visualization of sampled scalar, vector, and tensor fields of three spatial dimensions --- i.e. volume data. A key requirement of the photorealistic approach is real-time image generation. The goal is to provide tools of sufficient power and polish that scientists and physicians, not their assistants, will use them. Since no commercial workstation is capable of rendering usefully large volume datasets in real-time, the research plan includes a significant architectural component.