An Object-Oriented Virtual Geometry Interface

This paper describes an object-oriented software library called the Virtual Geometry Interface (VGI). The VGI is designed as a general, geometry representation-independent interface to geometric modeling, but is implemented speciically for mesh generation and computational mechanics. The design provides for multiple simultaneous geometric representations in a model. The design of the VGI eases the task of adding new geometric representations and creating new types of geometric entities. An innovative way of capturing topological relationships in the model has been implemented using a directed acyclic graph that is independent of the actual objects being linked together. A generic query mechanism, independent of the allowable entity relationships of the model, has been implemented for topological queries.