The VolumePro Real-Time Ray-casting System

Figure 1: Several volumes rendered on the VolumePro hardware at 30 frames per second. This paper describes VolumePro, the world’s first single-chip real-time volume rendering system for consumer PCs. VolumePro im-plements ray-casting with parallel slice-by-slice processing. Our discussion of the architecture focuses mainly on the rendering pipeline and the memory organization. VolumePro has hardware for gradient estimation, classification, and per-sample Phong illu-mination. The system does not perform any pre-processing and makes parameter adjustments and changes to the volume data im-mediately visible. We describe several advanced features of Vol-umePro, such as gradient magnitude modulation of opacity and il-lumination, supersampling, cropping and cut planes. The system renders 500 million interpolated, Phong illuminated, composited samples per second. This is sufficient to render volumes with up to 16 million voxels (e.g., 2563) at 30 frames per second