Arx1

代码说明：

说明：  选取四个点，自动判断是否在一个平面上。同一个平面上。则绘制一个多边形。不在一个平面，则以前三个点为底面，构成一个椎体。支持Move等转换命令，存图与开图，实现Jig交互绘制等。(Four points are selected to automatically determine whether or not they are on a plane. On the same plane. Draw a polygon. If it is not in a plane, the first three points are at the bottom, forming a vertebral body. Support Move and other conversion commands, save and open maps, Jig interactive rendering, etc.)