I modeled a very simple arched plank in 3ds max, uv'd it and put it into 3d coat. I painted the top of the mesh and everything looks fine, but when I export it and import it back in 3ds max and apply the material there is a weird issue with a grey line showing up in the center of the mesh. The UV's themselves are shared,…
Maybe it's unrelated, but I see that your UVs are too close to the border of the UV space: scale them down a little, and then export the diffuse map again from 3D-Coat.