Feature-based modelling in support of embodiment design

Feature-based modeling is of particular importance for the design process. This paper presents the basic steps of the design process and it shows that CAD systems that perform only geometric modeling are not fully capable of supporting the designer in an efficient way. The main requirements that a feature-based modeling system has to meet are discussed from the viewpoint of classical engineering design. We show that besides the ability to handle creation, deletion, and modification of form features and assembly features, additional operations become ncessary. These operations serve to maintain the integrity of a feature, if an edge or surface is modified (local operations) in the vicinty of that feature. We take the system IKA, which was especially developed to support the designer, as an exemplary prototype implementation to demonstrate the abilities and the performance of feature-based systems. In a previous paper Ä1Ü, we discussed a new classification scheme for form features, and w e showed a basic concept for feature-based design consisting of four levels (application-, definition-, representation-, and geometric modeling level).