面向网络交互设计的扩展CSG模型构造

针对网络虚拟设计中三维模型数据流量大，实时交互难的关键问题，提出了一种扩展CSG模型以减少数据传输流量．首先建立了模型的形体表征及操作结构，并对传统CSG树进行语法扩充以构造操作历程树，从而将产品模型分离为表现模型和表示模型等几部分．表现模型完成网络前端的交互设计，表示模型作为加工制造工程的模型重构基础，两者通过核心模型联系并集成，从而提出了一种基于扩展CSG模型的全新网络设计模式．然后基于ACIS几何引擎，开发了相应软件系统，并结合具体产品设计的应用验证表明，该模式提供了一种开展网络设计的可行途径．

Construction of Extend Constructive Solid Geometry(ECSG) Model for Web Interactive Design

A model called ECSG(Extend Constructive Solid Geometry) was built for decreasing the data-transferring in web interactive. The shape representation and operation structure of ECSG model is built first. Then based on the structure, a traditional CSG model is extended to build an operated history tree. By the ECSG model, the traditional product CAD model is divided into two parts: one is displaying model contained surface attributed for product design in client, the other is representing model contained the geometry attributed for CAM use in server. The two parts are connected by ECSG kernel model. The displaying model and representing model can work individually and integrate in one body. Also, a web-based interactive design system was implemented on the basis of ACIS geometry engine. It is shown that the ECSG model enhances the design system effectively by transferring design data economically, and it also provides a new pattern to realize web-based application.