Normal direction of triangles in opposite direction as light.

[oveddan]

Since the normal direction on a triangle depends on the order of the verteces, that means the normal will just point on one side of the surface and not the other. If a light then is pointing at the back of a triangle surface, where the normal is not pointing out of, is it correct that it should not affect the shading of that surface?

[danielepanozzo]

Yes, it is common to hide the "back side" of the triangles of a closed surface. https://en.wikipedia.org/wiki/Back-face_culling