Form of Projection投影的形成 Projection method When the line of projection passes through the object and the pre-established plane,there will be graphics produced on the plane.This method is called projection. 投影法： 投影法是投射线通过物体，向选定的平面投射， 并在该面上得到图形的方法。 Lines of projection Center of projection Projection Object Plane of projection 请点击鼠标左键显示后面内容 2