Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Information Models for Product Representation: Core and Assembly Models



Sudarsan Rachuri, Mehmet M. Baysal, Utpal Roy, Sebti Foufou, Steven J. Fenves, Eswaran Subrahmanian, Kevin W. Lyons, Ram D. Sriram, Conrad Bock


This report presents a revised and unified view of the NIST Core Product Model (CPM) [1; 2] and the NIST Open Assembly Model (OAM) [3]. The CPM provides 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 shared throughout the product lifecycle. The OAM represents the function, form, and behavior of assemblies and defines both a system level conceptual model and the associated hierarchical relationships. The model provides a way for supporting tolerance representation and propagation, representation of kinematics, and engineering analysis at the system level. The objectives of the report are: (1) to report on the revisions and extensions of the two models since their initial documentation; (2) to link the two models more explicitly than was done before; (3) to present the revised CPM/OAM as the basis, or organizing principle, of a product information-modeling framework that can support the full range of Product Lifecycle Management (PLM) information needs about a product; A case study illustrates the use of the CPM and OAM models to capture information during various design phases.
NIST Interagency/Internal Report (NISTIR) - 7173
Report Number


artifact, behavior, Core Product Model, data modeling, entity-relationship data model, form, function, information modeling, next-generation product development tools, Product modeling


Rachuri, S. , Baysal, M. , Roy, U. , Foufou, S. , Fenves, S. , Subrahmanian, E. , Lyons, K. , Sriram, R. and Bock, C. (2004), Information Models for Product Representation: Core and Assembly Models, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed May 21, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created November 30, 2004, Updated October 12, 2021