【摘要】 指出了组合体是基本几何体经叠加和挖切等方式组合而成的,但组合体的投影并不是各基本几何体投影的简单组合,而是会发生相应的变化.阐明了组合体投影存在投影外接触、投影内接触、投影半包含和投影包含现象,分析了该现象与组合体投影变化的一般规律,提出了以两基本几何体接触处的投影变化的角度绘制组合体投影的、可操作性强的指导图解组合体作图方法.更多还原

【Abstract】 The combination solid is composed of the basic shapes after digging and piling, but the projection of the combination solid is not the simple combination of the projection of the basic shapes.It is pointed out that the combination solid can be divided into the contact projection and the inclusive projection.A series of principles of interpreting combination form, addition or subtraction in space are presented,which will be useful to solve the problems of drawings of combination solid.更多还原