In current practice, design documentation often fails to support the activities of design understanding, communication, and redesign. A Design History Tool has been developed to improve current design documentation. This tool is a computerized design history that represents and plays back important information generated during the process of designing a mechanical system. This tool not only documents the final design results, but also documents the constraints developed and decisions made in the evolution of a product from initial specifications to final detailed design. This tool supports design understanding, communication, and redesign. It allows designers, manufacturing engineers, and management personnel to review and examine an existing design. For playback, the Design History Tool provides four major browsing capabilities: a} browsing design artifacts from isometric drawing, design hierarchy, to details of a product; b) browsing design evolution from the initial specifications to the final detailed design; c) browsing design rationales and alternatives behind each design decision; and d) browsing constraint dependencies. To enhance the browsing capabilities, different interfaces have been developed to allow the users to efficiently retrieve and easily understand the design information. / Graduation date: 1992