The complexity of modern products and design tools has complicated the exchange of design information. It is widely recognized that the capture, storage, and retrieval of design information is one of the major challenges for the next generation of computer aided design tools. This paper presents a model for the flow of design information that supports a semantics-based approach for developing information exchange standards. The model classifies design information into various types, organizes these types into information states and levels of abstraction, and identifies the various transformations that operate between the information states. The model is then applied to an example of a transmission for a cordless drill.