Study on Generation of 3D Assembly Dimension Chain

A new method to automatically generate the 3D assembly dimension chain was proposed in this paper. The generative rule to obtain the loop circuit and the method to generate the VGC (Variational Geometric Constraints) network for dimension chain was provided based on the VGC theory and a generation strategy of the assembly dimension chain based on 3D CAD drawing was also presented. After the closed-loop was specified by the user, the system will extract the assembly constrain relations and the dimension information needed according to mating trees from the assembly drawing to generate the VGC network, then search for the shortest path in the VGC network to prepared for the setup of the assembly data base for the dimension chain, eventually the assembly dimension chain can be automatically generated from the database according a certain method.