Open3d surface normal vector calculation

One 、 brief introduction

In computer graphics 3D surface , Strictly speaking, there is no surface structure defined on the mathematical level , Because the surface graphics in the computer are generally composed of triangles or polygons , Therefore, the so-called normal vector of the surface is actually calculating the normal vector of each triangle or polygon . Besides , A great use of surface normal vector is to adjust the light intensity at different positions of the surface , So that the object is more real （ For more information, please refer to ：OpenGL Learning notes —— light ( One )）, This can be said to be common in many surface displays .

Two 、 Implementation code

For the related configuration process, please refer to the previous article ：https://blog.csdn.net/dayuhaitang1/article/details/125269607?spm=1001.2014.3001.5502, Here is only the relevant source code .