Towards feature attachment

Abstract Feature attachment in generative, constraint-based cad systems requires unambiguous semantics that are easy for users to grasp and can reasonably be implemented in cad systems. A procedural semantics for attaching protrusions and cuts is proposed that addresses the problems found in generative, constraint-based cad systems. The solution also takes into consideration the legacies of cad architectures that have evolved from the paradigm of creating geometry using regularized Boolean operations.