# Normals HELP

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Hi, Can someone please try to explain normals to me. What are they, and how in the world would i calculate them using polygonal data. I really do not understand tbis. Thanks a ton. Levi

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Normals are a direction vector that points in the direction of a surface. Think of a plane, the normal of the plane is a vector pointing the direction the plane is facing.

You need them to do collision detection and to do lighting. To get a normal of a plane you take the cross product of two vectors lying on the plane. The cross product gives you the normal vector. The direction is important depending on which way it is pointing out.

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