中文摘要：

为了实现客户端轻量级网络协同造型，设计了基于B／S结构的协同造型系统体系结构。由于产品CAD模型信息不能用于网络共享，所以利用XML构建便于网络共享的中间模型的表达格式，将CAD模型转变成可供协同设计用户共享的中间模型。为了解决由于中间模型庞大而造成的同步协同延时问题，提出了基于环的面表示方法，减小便于网络共享的中间模型数据量。构建了客户端几何模型中从特征信息到几何元素信息之间的双向查询结构，解决了设计模型造型修改后的修改特征、修改拓扑关系和修改几何元素的获取问题。

英文摘要：

To implement the collaborative modeling which took the network as the center, this paper presented the collaborative modeling system structure based on B/S structure. The XML technology was applied to build the expression format to change the CAD model which could not be shared into the middle model which could be shared by the collaborative clients on the network. To solve the problem of the middle model is too huge to transmit on the limited internet bandwidth ; the face expression based on the loops was proposed. By this way,the size of the middle model can be reduced largely. The structure of bidirectional query between the features information, topological information and the geometric elements information was established in the geometric models. Thus the problem is solved,that is how to get the modified features, topological relationship and geometric elements after the design models are changed.