A standard neutral file format for facilitating apparel pattern data sharing among dissimilar CAD/CAM systems has been long awaited by the apparel industry. NIST has taken the approach to use the Standard for the Exchange of Product Model Data (STEP) methodology to develop an information model for the exchange of two-dinensional flat patterns. STEpbeing developed in the International Organization for Standardization (ISO), provides a representation of product information along with the necessary mechanisms and definitions to enable product data to be exchanged amongst different computer systems and environments.
STEP defines a specification language called EXPRESS that is used to represent the information model within STEP. This paper presents an EXPRESS information model, in a graphical notation, for the communication of structure and semantics of the apparel pattern data necessary to interoperate between different CAD systems. The information model supports the capabilities of representing the base pattern geometry, the sizing data, and the grading rules which are based on traditional X-Y pattern-grading methods. Prototype implementation of the information model is also described in the report.