unit normal vector

例句：

1. 1. The unit normal vector is perpendicular to the plane of thefigure.
   单位法向量垂直于图形的平面。
2. 2. In computer graphics, a unit normalvector is used to define the direction ofa surface normal.
   在计算机图形学中，单位法向量用于定义表面法线的朝向。
3. 3. The normal vectors are usedto calculate the distance between two points onthe surface.
   正常向量被用来计算两个点在表面上的距离。