Archived

This topic is now archived and is closed to further replies.

CoolTomK

Finding the Normal of a Face

Recommended Posts

CoolTomK    122
OK, I know that this has been answered before in these forums, but I cant seem to find an answer as to how you find the normal of a face when you have the three vertices, and the winding order(counter clockwise or clockwise) of the face. Thanks

Share this post


Link to post
Share on other sites
CrazySwede    122
You create to vectors like this.

Vector1 = Vertex2 - Vertex1
Vector2 = Vertex3 - Vertex1

Then the normal of the face is just the
crossproduct between these two.

VecNormal = Dot(Vector1, Vector2)

Oh, and I think you should normalize both
Vector1 and Vector2 before you calculate
the dotproduct.

Share this post


Link to post
Share on other sites
Beer Hunter    712
Yeah, although I wouldn''t normalise the vectors before taking the cross product. You would normalise the face''s normal after taking the cross product, so doing two of them beforehand is unneeded calculation.

Share this post


Link to post
Share on other sites