We describe configuration space visualization methods for mechanical design. The research challenge is to relate the configuration space geometry to the mechanical function of the parts. Our research addresses the fundamental design task of contact analysis. Contacts are the physical primitives that make mechanical systems out of collections of parts. Systems perform functions by transforming motions via part contacts. The shapes of the interacting parts impose constraints on their motions that largely determine the system function. Contact analysis involves deriving and analyzing these constraints. Designers use contact analysis to ensure correct function and to optimize performance. We illustrate contact analysis on the film advance of a movie camera.