This thesis presents the concept, development, and use of PriSM (Postprocessing of Spatial Mechanisms), an interactive 3-D graphical postprocessor for spatial mechanism synthesis and design programs. This device-independent system provides visualization, modeling, and animation of spatial mechanisms. New ideas and methods are described to simplify the interactive specification of scene rendering and color parameters using the international ISO standard for 3-D graphics, PHIGS (Programmer’s Hierarchical Interactive Graphic System), and its proposed extensions, PHIGS+. Perception and evaluation of spatial mechanism designs are significantly improved by the use of PHIGS+ functionality to produce animated models that are shaded, lighted, and depth cued. Examples are presented for the rendering and animation of spatial mechanisms on a Raster Technologies (Alliant) GX4000 workstation with a hardware-based PHIGS+ graphics subsystem, UNIX, NeWS, and C. In addition to color photographs and grayscale bitmaps of the PriSM implementation, the program structure and source code listing are fully documented. / Master of Science