机械cad的二次开发，利用BASIC语言绘制直齿圆柱齿轮-Mechanical cad secondary development, using BASIC language draw spur gear

程序显示三个面对象（球面，圆锥面和圆柱面）的线框图，用Z轴设定观察向上向量。-Procedures showed that the three surface objects (spherical, conical surface and cylindrical surface) of the wire-frame diagram, with Z-axis vector set up observation.