FreeCAD,开源的CAD软件源码,是一个很好的学习图像处理的参考-FreeCAD, CAD software source code, open source is a good learning image processing reference

用inventor 软件绘制的开关管的3D图像，有定位套和真空管-Using the inventor software to draw the 3D image of the switch tube, there are positioning sleeve and vacuum tube