CAD二次开发，实现了用户交互的一些命令，以及用户选择等命令，需要配置CAD2012环境才能查看代码成果-CAD secondary development, the realization of the user interaction some commands, and user to select commands, such as CAD 2012 need to configure the environment to see the code

这个代码使用AutoCAD的界面API，来使用AutoCAD自带的界面类来做用户交互方面的设计-This code is using the AutoCAD UI API to create forms for user interacting with AutoCAD

自定义绘制多种类型曲线，通过ObjectARX+vc实现多种曲线的编程实现，与用户交互处理-AutoCAD self polyline draw