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The report presents a core model for representing design information, motivated by the perceived needs of next-generation product development systems and drawing contentlevel requirements from a related study of design information flows. The core model was synthesized from a comparison of several independently-developed design artifact representations. The primary objective of the report is to provide a base-level product model that is: not tied to any vendor software; open; non-proprietary; simple; generic; expandable; independent of any one product development process; and capable of capturing the engineering context that is most commonly shared in product development activities. The core model focuses on artifact representation including function, form, behavior and material, physical and functional decompositions, and relationships among these concepts. The model is heavily influenced by the Entity-Relationship data model; accordingly, it consists of two sets of classes, called object and relationship, equivalent to the UML class and association class, respectively. It is expected that the core model may eventually serve as a precursor for STEP in the lifecycle of a product, capturing all information relevant to the ongoing design process until the product design is firmed up, approved and committed to purchasing or manufacturing. Aspects of extensions of the model in these directions are discussed.

The initial core product model (CPM), developed at NIST for the support of in-house research projects, has been extended to create CPM2, intended to support a broad range of information relevant to product lifecycle management. CPM2 is a generic, abstract model with generic semantics. CPM2 gives equal status to three aspects of a product or artifact: its function, its form, and its behavior. Thus, CPM2 can support functional reasoning about a product in the conceptual stages of design, the recording and the modeling of its behavior in the postdesign stages as well as the “traditional” design phases. Three levels of CPM2 models, de-noted as the conceptual, intermediate, and implementation models, are described. Extensions of the initial CPM are briefly pre-sented. The facilities in CPM2 for building experimental intermediate systems are demonstrated and a short illustrative example is given. The full practical evaluation of CPM2 will require the development and use of implementation models.

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