I've done some searching, and found this: http://answers.unity3d.com/questions/8969/why-is-there-such-a-huge-disparity-in-polycount-be.html I'm doing a cloth simulation, and this bothers me. I have duplicated vertices and indices, which leads to Contraints failure. There are no constraint for my cloth where the seam happens! Original Model in 3dsMax. Here I just simply log the vertexCount and triangles.Length. And this is what I got in Unity: Is there a way to avoid the seams, and get the non-duplicated triangles?