Modelling generic product structures in STEP

Industrial companies need powerful data modelling mechanisms, e.g. classification, for the description of their products. The companies that adapt their products to the needs of individual customers in a routine manner have perhaps the most urgent needs. They must efficiently describe large numbers of product variants. STEP Application Protocol 214 (AP 214) for the automotive industry also addresses the modelling of product variants, i.e. generic product structure modelling. In addition to AP 214, the same mechanisms are needed in other standardization efforts as well, e.g. STEPLib of AP 221 and PLIB. STEP, however, does not include a mechanism for using classification and inheritance for modelling products of an individual company. These facilities are included in EXPRESS, but EXPRESS can only be used for describing the data schema to be standardized. The fundamental structure of STEP, therefore, prohibits a company from modelling its products in an object-oriented manner. This is an issue that may seriously affect the future of STEP as a general product-modelling methodology. The problems and possibilities of extending STEP in this direction within its current structure are discussed and a new mechanism is outlined as an alternative solution. (C) 1999 Elsevier Science Ltd. All rights reserved.