Speaker:  Peter Shirley
Affiliation:  Computer Science Department, University of Utah
Date:  10/14/99 - Thursday
Time & Location:  4:15PM, 101 Phillips
Title:  Ray Tracing for Interactive 3D Computer Graphics

Graphics boards have become so inexpensive that soon every PC will be sold with interactive 3D graphics capabilities. The boards are all based on the "z-buffer", which uses fast memory to accelerate a loop over all polygons being rendered each frame. Ray tracing, an alternative to the z-buffer which loops over all screen pixels rather than all polygons, is usually considered too slow for interactive applications. Instead, it is used in applications where visual quality is more important than speed. The visual quality arises from ray tracing's ability to simulate shadows, mirror-like reflections, and easily programmable shading, all of which are difficult to implement in a z-buffer architecture. This talk will challenge the view that ray tracing is only useful for batch applications. A parallel ray tracing program developed at the University of Utah gives an existence proof for the feasibility of interactive ray tracing for some high-end visualization applications. The raw systems issues and asymptotic time complexity of the z-buffer and ray tracing will be used to argue that the ultimate impact of ray tracing will be felt in a variety of more common applications. This work was done in collaboration with Steve Parker, Bill Martin, Peter-Pike Sloan, Yarden Livnat, Chuck Hansen, and Brian Smits.