Hi everyone, mhcannon asked me to post this here as it may prove useful to some of you, and I'm happy to oblige.

Right, I've noticed that some people are having problems rendering their sub-d meshes in Mental Ray. This is most probably because mental ray cannot support a sub-d mesh that has tri's in the base mesh. A neater way to render your sub-d's is to use Mental Rays approximation editor. This will attach a node to your mesh, and when you render it will look just like a sub-d. Here's how you do it.

1. Select your mesh and open up the approximation editor by going to window -> rendering editors -> mental ray -> approximation editor , and it will pop up.

2. In the approximation editor, under the bottom most set of options next to subdivision approx, click on create then edit . The attribute editor should open.

3. In the attribute editor you need to set a few options depending on how you want your sub-d to render. Set the approx method to length/distance/angle , then set the length. The lower the value you use for the length, the smoother your sub-d will be, but it will take longer to compute. Make sure that view dependant is checked on, and set the mesh conversion to none if your mesh is completely made up of quads, or to triangles to quads if you have tri's in your base mesh. It is important to set it to triangles to quads if you have tris, otherwise the sub-d won't render.

4. Thats it, and your polygon mesh should now render as a nice smooth sub-d (5)! :attn: