Research On Technology Of Virtual Assembly Based On XNA

Recent days, with the popularization of computer graphics rendering technology and the improvement of virtual assembly technology and systems, it turns out to be more and more important on how to combine the traditional virtual assembly technology and the newest 3D computer graphics tools. The next generation virtual reality environment by Microsoft, XNA was adopted in the application to Design for Assembly areas in this paper, giving the first report on the XNA virtual assembly technology. The research enriched the virtual assembly theoretically and technically, promoted the interchange and development in different subjects, and made the technology more suitable for the engineering situation that give it great economic value in the real application.Firstly, the assembly hierarchy information model mapping from CAD system to VR environment was set up, holding the initial designing intention of product assembly sequence and path, and then the transforming standard of triangle or polygon patch model came into existence and its method on Pro/Engineer to XNA was given. Then researched the algorithm of imformation extraction based on Pro/Toolkit and its function operation flow, then developing system of Pro/Engineer was come true. The data model was expressed as XML format, and mapped to XNA virtual environment, was took as an input of the next shooting script modeling system.Secondly, considering that the current virtual assembly animation technology lack of a rapid standard manufacturing method and flow, the concept of shooting script was introduced and a new modeling manner combining shooting script with assembly hierarchy information was put forward. The method could actualize the rapid construction of virtual assembly environment and vividly exposition of animation effect. The scene and sound materials was made according to the assembly requirement. The shooting script model was composed by four modules such as action, shot, scene and sound. Each one containing the material was integrated into the assembly script model that output the optimized list of assembly time, path and sequence. The referring model also was expressed as XML format and parsed by XNA virtual environment, then understood as a keyframe animation of assembly.Thirdly, by researching on the X format data structure and its hierarchy an OBB collision detection algorithm based on X models was designed, a bounding box binary sort tree with the oriented projection node as unit has been built. By using the method of inorder traversing, a separating axis detection table was established to raise the speed of detection. In the accurate judging process, the solution for triangle intersection in the space becomes to a problem solved in the plane through transformation of coordinates system, thus the algorithm has been simplified and the detection speed has been raised, and then applied to HCI assembly and disassembly with computer peripheral equipment. On the other hand, a sort of bones animation technology based on X hierarchy model structure was introduced which worked for mechanism motion simulation combined with XNA bones animation class.Finally, a virtual assembly system based on XNA composing by four modules of virtual display, automatic assembly, intetactive training and motion simulation, was developed to validate the technology discussed above, and then examples were provided to illustrate the rapid solution process of virtual assembly simulating animation.