FEATURE MODELING AND CONVERSION - KEY CONCEPTS TO CONCURRENT ENGINEERING

Feature modelling is a relatively new development in CAD/CAM. Whereas in solid modelling only information about the geometry of products is stored, in feature modelling also functional information is stored in the product model. One aim of this article is to give an overview of the main concepts in feature modelling, another is to indicate the issues in feature modelling that are relevant for further research. There is much confusion about what features actually are, and therefore definitions, classifications and examples of features are first given. Because feature modelling builds on solid modelling, an overview of advanced solid modelling is given, with emphasis on the concepts of parametric and constraint-based modelling. Attention is next focused on representation of features. The two most important ways to define features in a product model, feature recognition from a geometric model and design by features, are then discussed. Design by features is illustrated by the GeoNode system. One of the main themes in this article is that for different applications, different features are required, and that therefore there is a need for automatic conversion between features. Such conversion is of particular importance for the support of concurrent engineering, in which several engineers from different disciplines work simultaneously on the design of a product.