投影制图中的新概念——逆射与相交

Reflection and Intersection in Projective Drawing

为了更有效地训练和提高学生的空间思维能力和三维构形能力,在画法几何与投影制图的教学过程中,有必要增加一个从二维向三维转换的教学环节,即从几何元素的二维投影表达出发,实现三维形体的重建和三维环境下的定位、测量。在画法几何与投影制图的教学过程中,应用作者开发的图形教学软件Projector,操作者可以方便地从空间点、线、面、体,得到平面投影,也可以从已知平面投影出发,求解空间几何问题。

In order to develop the ability of the students in spatial modeling, it＇s necessary to add a step to transforming 2D to 3D, named ＂reflection and intersection＂, into the descriptive geometry training and drawing, which means to perform 3D rebuilding, locating and measuring, from 2D geometry elements. With the help of software ＂Projector＂, the operator will be able to get 2D projects from 3D point, line, plane and solid, or to solve 3D problem from 2D projects in 3D environment.