Visible seam when rendering with a Sub-D approximation node

When rendering a high detail mesh via a displacement map and a Sub-d approximation node, there is a visible seam in the UV border.
This is due the fact that Maya (2008 and up) is using a new algorithm called CCmesh to subdivide the mesh at render time via the approximation node.

This algorithm is much faster that the old one, however there is a logged Bug against it that will smooth the UV border edges as well.
You will only notice this visible seam when using a mesh with multiple UV shells.

You can disable CCmesh by selecting the mesh and applying the following MEL
addAttr -ln "miExportCCMesh" -at bool mentalraySubdivApprox1;

where “mentalraySubdivApprox1” is the name of your approximation node.

 

This issue is expected to be fixed in a future release of Maya.