RULE-BASED FEATURE RECOGNITION FOR 2.5D MACHINED COMPONENTS

Feature recognition from a solid model can be treated as a pattern-directed search for specific shape properties. However, to extend the range of features and of interacting situations in which it can be of use, there is a requirement to characterize a richer set of shape properties on which search will be based. Sequences of edges that are within the convex hull of a face ('remnant' loops) and edge loops that are shared between several features add to the discriminating power of feature hunting techniques. These shape properties have been exploited in the implementation of a feature analysis system that operates on 2.5D object representations in a solid model and which derives a regional feature structure suited to three-axis machining. The motivation for its development was to provide a bridging link between a solid model representation and a knowledge-based, computer-aided, process planning system for prismatic parts.