I'm implementing a tesselated cube that I will be cutting up in various ways. Tesselation works great, however, I have an unexplained visual artifact that has me completely stumped. At higher division levels, I get a triangle-shaped artifact that appears on the face. This artifact becomes more and more localized as the division level increases. I have attached the following screenshots with all vertex normals drawn. My first intuition was the face normal was incorrect, but this does not appear to be the case. ANY advice is helpful. I'm completely stumped. Division 3 : http://www.nyx.net/~smanley/opengl.jpg Same model, Division 6: http://www.nyx.net/~smanley/opengl2.jpg Inside the box: http://www.nyx.net/~smanley/opengl3.jpg http://www.nyx.net/~smanley/opengl4.jpg Has anyone seen anything like this before? Thanks, Steve

Looks like an incorrect normal to me.

I agree with you 100%, however, the normals at each vertex are as drawn - e.g, apparently correct.

Hence my confusion. I don't disagree that it is the obvious cause, but I'm wondering if there are any possibilities, as I have pounded on this for awhile, and the normals appear to be correct.

Definately looks like an incorrect normal.. maybe your vertex buffer memory is corrupted ?

Will check on the memory situation, that is possible, but I'd expect the vertex normal representation on the line to be flawed then as well.