Development of Step-Based Dimensioning and Tolerancing Data Model

Abstract

STEP product model is an effort to develop an international product modeling standard by the International Standards Organization (ISO). The product model involves both working standard and information models. As product accuracy becomes tighter, dimensioning and tolerancing (D&T) plays an important role in product lifecycle. It is an important issue to develop a D&T data model based on STEP. This paper describes the development of a STEP-based D&T data model. Required information to build a STEP-based D&T scheme is investigated. Implementation of such a data model and construction of a product D&T specifications based on the model are then described. Three examples, including a single part with an interface for tolerance analysis application and an assembled product, are used to illustrate the usage of the data model.