Machine Understanding of CSG: Extraction and Unification of Manufacturing Features

Constructive Solid Geomety (CSG)-albeit a concise, powerful, and informationally complete scheme-does not explicitly present certain high-level conceptual information, which is directly available from traditional engineering drawings and has been extremely useful for manufcturing processes. Such manufacturing fetures as chamfer, round, fillet, bore, and neck are typical examples of this kind of information. The fact that CSG is unambiguous but not unique, however, has posed great difficulties in the development of algorithms capable of understanding CSG and making it more useful for manufactuing. We propose a general apporach, based on principal axis and tree reconstruction, to extract and unify feature representations while retaining the simplicity and conciseness of CSG.