不同CAD系统间图形相互转换的研究与实现

THE RESEARCH AND REALIZATION ON MUTUALLY DRAWING TRANSFORMING BETWEEN TWO DIFFERENT CAD SYSTEMS

为了实现不同CAD系统之间图形的相互转换,首先必须以形式上通用、但格式细节上有差别的IGES文件为依据。在各自系统中选一种系统支持的软件为工具,对原图形文件进行扫描检索,再生成对方系统所能接受的IGES格式的文件。然后,利用局网通讯协议传送后,在对方CAD系统的屏幕上重现。本文介绍了两种方法。一种方法是生成只包含直线项目的IGES文件。重现的图形与原图形状完全相同,但占存储空间较大,有时不能利用对方的编辑功能进行修改。另一种方法是生成以各类基本图形项目为基础的IGES文件。它可以克服上述不足之处。但必须预处理某些信息。所开发的软件是用于AutoCAD与TekniCAD系统之间的图形相互转换。其设计思想同样可以解决不同CAD系统之间相互转换。

In order to realize the mutually drawing transforming between two different CAD sys- tem,first of all we must be on the basis of the IGES files,which are formally general but have many differences on format in detail.On each CAD system a system supported software has been chosen as a tool.The original drawing will be scanned and searched, and an IGES format file that the other system can receive will be generated.And then,after we use the local network protocol to send it,the drawing can be reappear on the screen of the opposite CAD system. Two methods of transforming are presented in this paper.One method is to generate the IGES files that only contains the items of line.The reappearance of the drawing is the same as the original,but it needs much storage space and sometimes cannot utilize the editor's function in the opposite side do revison.The other method is to generate the IGES files based on all types of drawing items,it can overcome the above deficiency,but the information must be preprocessed. The interactive software correspondingly developed is used to transform Auto CAD's drawing from or into Tekni CAD's.The design idea can also solve the problem on the transforming drawing from one CAD system to another.