Research And Implentment Of Identifier-based Feature Modeling System

The technique for parametric feature-based modeling is the key technique of modern CAD system .In this dissertation, some key techniques are researched and applied to the program written by the author, The main subjects and achievements are included as follows:With OOA and OOD, The feature-based modeling system GDS is designed .Data structure and system structure for the system is given ,the functions for the feature-based program is discussed.An identifying system is designed and implemented which can give every geometric element an exclusive identifier. From the identifier, corresponding geometric elements can be gotten. This provide a basis for further application such as feature editing and so on.Unlike traditional method which modifies B-rep or CSG to adapt feature-based modeling, the feature-based represent model for the product which Based on identifying system is presented .The represent method need not change the B-rep of solid model and can map feature-based model to B-rep-based model.A new approach to parametric design is presented ,which is Child-Graph based , and which design a 2D sketch in sequence .In this approach ,the sketch is designed with simple elements such as points , segments, circles or Child-Graphs which is combination of above simple elements ;geometric elements is designed in sequence can implement the function of unwell defined(less-constrain) parametric design.2Dand 3D constrains is treated consistently.Aimed at that error may occur in Feature-editing, Feature-editing is researched, Based on the topological mapping algorithms ,the function of feature editing is implemented.