View Full Version : Tesselation nightmare!!

05 May 2007, 10:39 PM
Hi dear mentalray users...
In this post there is an image which perfectly illustrates my 'nightmare'
As you can see i cannot get smooth enough tesselation for this rendering wihtout fantastically increasing my render time.
Can you please advice me on some good settings for a surface approximation node? I have tried and tried to get to middle grounds but it just seems impossible. All geometry is nurbs btw. (

PS: the render region (smaller patch) which is clearly visible due to the hue change took 6 minutes to render (core2duo 2.1)

05 May 2007, 12:44 PM
Ok... no answer.
Let me ask you one more thing then: how can I force MR to use the tesselation i
see after tweaking the respective attributes on a nurbs surface. I've tried set nurbs tesselation, attribute spreadsheet and manually inserted the values but MR just ignores them.
Thank you!

05 May 2007, 01:03 PM
Did you plug surface approximation node as override for all of your surfaces?

That would stop mr from looking for tesselation options in surface shape node. But I think it's better to work with mr's surface approximation node.

05 May 2007, 02:11 PM
In fact, no, i didn't plug in any surface approximation nodes or overrides (but there such nodes in the scene).
However I found out that inherited tesselation does work when rendering with mental ray but it appears to behave wonky in this particular scene. Anyways it would HELL to export everything and hope it works in a new, clean scene. Do you have any more ideas how to ensure maya tesselation in these mental ray renders ?

05 May 2007, 03:01 PM
I haven't worked with maya's tesselation options much, but this is how i would setup my MR tesselation.

Go to "Window->Rendering editors->metal ray->Approx editor", create NURBS Approx node and tweak it. Now go Render settings and under Render Options find overrides and plug that node into Tesselation.

If it's still too time expensive you can create two Approx nodes, one with high settings for close objects and one with low settings for other, and asign them to objects from within the Approx editor.

05 May 2007, 04:52 PM
Try to uncheck 'Export Nurbs Derivatives' in Render Settings -> mental ray -> Translation -> Performance tab.
See what it does for You.

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