摘要
立体几何造型系统是集成化 CAD/CAM 的核心,而内部描述物体的数据结构则是几何造型系统的核心。本文介绍了将立体几何造型中结构立体几何(CSG)数据结构转换成边界表示(B-Reps)数据结构的方法。作者采用了 CTIPS 系统的二层数据结构的 CSG 作为转换的基础,而作为转换结果是一种对称形式的 B-Reps 数据结构。由于该 CSG 数据结构是由网格信息组成,完整物体的 B-Reps 的产生将依赖于网格信息,因此转换分两步进行:首先从 CSG 信息生成一个网格单元的 B-Reps,然后将网格单元的 B-Reps 合并生成完整零件的 B-Reps。目前已在超小型机上实现了这个转换。
It is well known that geometric modeling is the kernal of intergrated CAD/CAM whiledata structure of object description is the key in 3-D geometric modeling.In this paper,amethod generating B-Reps(Boundary Representation,a data structure of geometric mod-eling)from CSG(Constructive Solid Geometry,another data structure)is described.Atwo-lay data structure of CTIPS system is adopted as CSG,the basis of generation,the resultof which is a symmetrical B-Reps.As CSG is made up of mesh information,the B-Reps forpart depends on B-Reps of mesh.In this generation,the B-Reps mesh cells come from CSGfirst,then the part B-Reps is merged by the cells.Currently,this conversion has been realizedon super-minicomputer VAX11/780.
出处
《中国纺织大学学报》
CSCD
1992年第2期1-9,共9页
Journal of China Textile University
关键词
数据结构
几何造型
CAD
CAM
computer aided design
computer aided manufacturing
computer applications
modeling
data structure
geometric modeling
boundary representation
