基于图元法的AutoCAD参数化设计与绘图

对于结构型式多变、复杂的常用件(如轴、齿轮等)的设计，因为其应用频率高，绘图工作量大，适合于用图元法对其进行二次开发，以提高工作效率。图元法是对所开发的零件进行分析归纳，总结出高度概括的图元，用这些图元基本上可组合出该类零件的所有结构，然后对各个图元编程，并赋予相应的约束参数。机械零件设计中，对形状不相似的图形采用图形元素拼合法进行设计绘图，既简单，又方便，可以将设计人员的主要精力从繁杂的绘图工作转移到零件的结构设计上，提高产品的设计效率。本文以Object ARX作为开发工具，以机械常用的零件为例，讨论了图元法在AutoCAD 2000中二次开发的应用。用基本的图形对象创建图元，通过图元拼合法生成零件图。

AutoCAD parametric design and drafting based on geometric primitive approach

This paper discusses the application of Geometric Primitive Approach to the redevelopment of AutoCAD 2000 by using Object ARX as a tool and common mechanical parts as examples. Graph element is set up by basic drawings, and drawings of different mechanical parts are made by graph element assembly. Because of constant use and great amount of drafting work, the design of some commonly-used parts with changeable and complicated structures such as axles and gears is suitable for using Geometric Primitive Approach to redevelop in order to improve working efficiency. Geometric Primitive Approach is to analyze the parts to be developed and sum up the Geometric Primitives, which can be used to constitute all the structures of this kind of parts. Then each Geometric Primitive is programmed and is given a corresponding controlling parameter. In the designing of mechanical parts, it is easy and convenient to use Geometric Primitive Approach to design different drafts, and the designers can devote all their energy to the design of parts instead of to the complicated drafting so that efficiency can be improve.