Geometric Reasoning for Feature Recognition

Jung-Hyun Han

December 1995

For CAD/CAM integration, it is essential to recognize features such as holes, slots and pockets, which are associated with distinctive manufacturing processes. Vandenbrande and Requicha developed a feature recognizer OOFF (Object Oriented Feature Finder) in the late 1980s. In OOFF, features are recognizable by processing the characteristic traces, called hints, they leave in the nominal geometry of a part. This paper presents a significant extension of OOFF, based on the generate, test, and repair problem solving strategy. The new feature recognizer is armed with new robust algorithms for hint generation and geometric computation. Given a hint H, the generate step proposes a maximally extended removal volume V. The test step checks if the proposed volume V can be removed without intruding the part. If so, a solid feature that can remove V is recognized. Otherwise, V may be repaired such that its volumetric subset can be removed as a valid feature. \\ \\