Investigation of declarative feature modeling

Features are composed of not only geometric entities, but also intrinsic/extrinsic geometric relations, hierarchical relations, size and location limits, and other higher level attributes. In the declarative approach, a feature is defined as a set of constraints applied to geometric entities or primitive volumes. Declarative modeling is facilitated by building blocks which enable constraint specification between feature entities. This paper will describe the methodology for the development of feature building blocks using standardized sets of geometric constraints, which can be used in the construction of graph based representation of features that are implementation independent. The declarative approach presented here takes advantage of two types of generic systems available commercially: geometric modeling core packages and constraint solvers. A graphical user-interface is also described for defining and archiving generic features in a library.