Stop-motion animation brings the constraints of the body, space and materials into video production. Building on the tradition of video prototyping for interaction design, stop motion is an effective technique for concept development in the design of Tangible User Interfaces. This paper presents a framework for stop-motion prototyping and the results of two workshops based on stop-motion techniques including pixillation, claymation and time-lapse photography. The process of stop-motion prototyping fosters collaboration, legibility and rapid iterative design in a physical context that can be useful to the early stages of tangible interaction design. Keywords Stop-motion, Pixillation, Claymation, Animation, Prototyping, Tangible User Interfaces.