This application had two general design criteria: it was dynamic and three-dimensional. The simulation was dynamic in the sense that it modeled phenomena that changed over time. The output from the simulation was a series of files, referred to as frames, that showed the new positions of the fibers, fluid markers and the new velocity and pressure fields from points in the main iteration loop. Thus, the graphics system had to present these frames in sequence; the PS 340 system can present this sequence fast enough to impart a sense of motion.