# Line - Triangle Collision and Normals

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bovinedragon    122
Any one have a good link for this? I have read a few sites on this subject, and they use the normal to the plane. I have all the normals of the vertexes, how would I convert this into the normal of the plane? I tried adding up the components, then diving by three. That makes the right vector, but its not normalized right? What is the difference between a normalized normal and a unnormalized one? Isnt it still the same normal, just a different length? Does this affect how it renders(like for lighting)?

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Zipster    2359
You can calculate the triangle normal directly from the vertices, without using their normals. Just do (C-A)x(B-A) for vertices A, B, and C, and then normalize.

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bovinedragon    122
well i already have the vertex normals, so i think it would take less time to derive the face normals from the vertex normal right?

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aCynic2    102
Quote:
 Original post by bovinedragonWhat is the difference between a normalized normal and a unnormalized one? Isnt it still the same normal, just a different length? Does this affect how it renders(like for lighting)?

A normalized vector is a unit vector. It's a mathemactical description of a geometry's orientation.

Unnormalized vectors are typically used to describe magnitude/distance AND direction.