Feature validation in a feature-based design system

The Loughborough University of Technology Feature-Based Design System (LUTFBDS) allows detail design to be carried out in a computer aided design (CAD) environment by the addition of form features to stock material or part-machined components. An iconic user interface assists in the description parts in terms of a set of primitive features such as holes, pockets and slots or higher level compound features such as patterns of holes and counterbored holes. This feature representation is generated in parallel with the geometric data structure of the underlying boundary representation solid modeller. The feature representation is useful for a range of downstream manufacturing activities, but our research focusses on the integration of CAD with process planning. LUT-FBDS functions allows the designer or manufacturing engineer to progressively construct the final geometry of a part, and facilities are provided for the designer to modify parameters which relate to feature dimensions, location, orientation and relationships with other features. These changes may result in changes to the feature representation and hence there is a need for feature validation to ensure the integrity of the model.