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vinothrajendran4
11-16-2016, 06:58 AM
Hi Everyone,
I am new to openGL, I would like to know the calculation involved in finding the normal for triangle with four faces in 3D.....

Silence
11-16-2016, 07:31 AM
A triangle with 4 faces ?

If you have a triangle ABC, then the normal of it is the cross product of the vectors AB and AC.

vinothrajendran4
11-16-2016, 09:22 PM
thank you Silence for your reply.

But i am looking for normal calculation involved in Egypt Pyramid (which has 4 faces and a polygon base)....

Silence
11-18-2016, 12:08 AM
This is exactly what I said. Do that for each vertex of each of your triangles. For pyramids, normals at each vertex are the normals of the face they belong to.

__bob__
11-21-2016, 06:21 AM
A triangle with 4 faces ?

If you have a triangle ABC, then the normal of it is the cross product of the vectors AB and AC.

And dont forget to normalize the result!

Silence
11-21-2016, 07:28 AM
And dont forget to normalize the result!

Right ! Otherwise it won't be a normal.