ABSTRACT
Currently, three-dimensional CAD software has been widely used in China. The thought of product design has significant changes. From the parts to the assembly design is entirely based on the completion of the threedimensional environment. In the three-dimensional CAD design environment, the assembly product information expressed in the form of tree structure. Centering on the component object, all the product design data, process data and production data organization in three-dimensional structure of a tree. In different periods of building product structure tree, the main source of information is the contents of the 3 d assembly information. Assembly is composed of a series of component model assembly components structure tree plus with words of annotation and attribute data. Assembly model and part model in the form of numbered layers of father-child nodes reflected in the structure tree.
