Functional modelling using an object-oriented design system

Abstract

A significant progress in the development of CAD-systems was the extension to functionalities handling more than pure geometry (such as points, edges, surfaces and bodies), i.e. data concerning the technical product structure (such as physical and mechanical properties). These efforts are made to accelerate the engineering and design process, to avoid errors during the engineering process and to make use of the product-related data in electronic form in the later phases of the product life cycle. One approach to extend the CAD-functionalities is feature-based design, which aims at representing some apects of the product separately. Yet it is necessary to include the different kinds of features (describing different properties of the product) into a complete model. Despite the efforts of the institutes of standardization a satisfying product model has not yet been defined. A possible solution of this problem may be the definition of a meta-language for the engineer allowing him to build his own product model including his own characteristical entities of the product. This meta-language must be very simple to understand and to extend; the derived sentences (the instances of his product model) must be exchangable and combinable. The object-oriented concept and the different components (terminals or alphabet, non-terminals or symbols and deriving rules) of this meta-language are discussed in this paper.