vb调用cad的开始程序，是cad与vb的接口，可以作为开发cad的前序程序-vb call cad the beginning of process, the cad with the vb interface can be used as a pre-order program development cad

实现proe二次开发的弯曲级进模CAD系统功能，用在建模上。-Proe secondary development to achieve a bending progressive die CAD system functions, used in the modeling.

基于lisp语言的cad二次开发，可以用来求得地块面积，也可以非常方便的求得多边形面积。-Obtained polygon area