nurbs not tessellating in MR
 

Hi - this picture should indicate the problem pretty well. It's basically as if I'm getting base tessellation on my nurbs surface.

This surface renders smoothly in Maya software.

I'm using Mental Ray with Maya 6.

Raytracing is on for two point lights.

The surfaces are using advanced tessellation attributes with 4 per u and v span.

I'm sure it's something simple I'm just not getting but I cannot seem to find it.

Any ideas much appreciated.

The answer is in the question
 

Found it myself. For anyone interested the answer lies in the question. The untessellated surface is what you get when you check the 'Advanced Tessellation' box in the attributes of a NURBS surface. The advanced tessellation instructions are for Maya software render and evidently cause problems with Mental Ray. :cool:

here's the picture at preview quality.