Three-dimensional net shape analysis for manufacturability evaluation

A formalism for symbolic representation of a three-dimensional model to aid geometric reasoning is presented, and its use for knowledge representation and in a control structure is explained. A robust feature-based design approach based on this formalism has been developed to provide meaningful geometric and topological properties for manufacturability evaluation while providing wider geometric coverage. Local shape analysis is based on symbolic representation, and global shape analysis is performed by extracting the skeleton from the decomposed object. This extracted skeleton is used to locate and measure global shape characteristics, thus allowing the system to perform geometry-based simulation of the solidification process automatically. The extracted skeleton is regarded as a set of final freezing points in the solidification process. For knowledge acquisition, binary syntactic primitive pairs have been established to aid in high-level symbolic geometric reasoning. Symbolic reasoning tables based on binary primitive pairs provide five stages for proper knowledge invocation