1. A computer-based feature recognition method for use in recognizing instances of features in a solid model that are identical in shape to a user-defined feature that is defined using a fixed set of connected feature faces and base faces in the solid model, said method comprising: generating a predetermined set of attributes to be used in representing the user-defined feature; and using the feature faces and the base faces of the user-defined feature along with said set of attributes to produce a feature graph, comprising attributed nodes and arcs, which captures the shape of the user-defined feature; and using the solid model along with said set of attributes to produce a part graph comprising attributed nodes and arcs; and using matching involving the feature graph and part graph to recognize instances of features in the solid model that are identical in shape to the user-defined feature.