Ronald S. Chong
Difficulties with part oriented solid modeling tools have motivated the development of a derivationbased solid modeling system to aid in preliminary submarine design tasks. The projected system is a graphically editable geometric rule system based on Extended Pattern Grammars with Variables (EPGVs). This paper reviews relevant characteristics of Boundary Representation Modelers, Featurebased Modelers and Extended Pattern Grammars, then establishes a fundamental relationship begveen the Inference Dependency Graph that is constructed during an EPGV derivation and a parametric system Feature tree. The primary technique involved with editing an EPGV derived model is identified with Dependency Driven Backtracking, and a description of the process is presented.