Research On The Real-Time Transmission Of Geometry Model Data In Distributed Virtual Environment

As the applications of Distributed Virtual Environment(DVE) becoming wider and wider in recent years., the demands of interaction, real-time, third dimension are growing higher. At the same time network bandwidth and delay become the main limitation of DVE. Since DVE widely uses 3D mesh models to describe the whole environment, the data of 3D mesh models becomes one of the main data needed to transmit in DVE. To solve the bandwidth and delay limitation on DVE, and meet the demand of real-time, one of the method is trying to reduce the transmission amount of geometry model data.To ensure the real-time demand, this thesis divides the research on the real-time transmission of the 3D mesh models into two parts. Firstly, an algorithm of Edge Collapse is presented which combines curvature and the border edges with the quadric error metric method. It simplifys the original mesh model when it is not turely needed to be transmited. Preserving both the topological structure and the shape feature of the original mesh model, this method degrades the complexity of the model. Secondly, this thesis introduces a model simplification method based on the PM representation with a rule of reducing computing amount. It presents a method in which a weight is computed for each edge, and the edge with smaller weight is always removed earlier. Finding the triangle with smaller weight is used to replace finding the edge with smaller weight, which improves the quality and efficiency of the simplifica -tion. In the end, the output model of the first step is changed into a coarse model anda series of detail information, so when in transmission we can transmit the coarse modelat first, and then transmit the detail information gradually.