: In a collaborative computer-supported engineering environment, the interoperation of various applications will need a representation that goes beyond the current geometry-based representation, which is inadequate for capturing semantic information. The primary purpose of this paper is to discuss a semantically-based information exchange protocol that will facilitate seamless interoperability among current and next generation computeraided design systems (CAD) and between CAD and other systems that use product data. We describe an ontological approach to integrating computer-aided design (CAD) and computer-aided process planning (CAPP). Two commercial software applications are used to demonstrate our approach. The approach involves the development of a shared ontology and domain specific ontologies in the KIF (Knowledge Interchange Format) language. Domain specific ontologies--which are feature-based—are developed after a detailed analysis of the CAD and the CAPP software. Mapping b...