View Full Version : mental ray: letters on a mapped logo disappear in final render

03 March 2004, 05:15 PM

I am trying to use mental ray, but I am finding that the renderer sometimes 'erases' part of the image.

for example I have a logo mapped to a surface and some of the letters in the logo disappear. this also happens when I have fine geometry.

has anyone seen this before and know of any solutions?


03 March 2004, 05:28 PM
Have u try to set up ro production preset?

03 March 2004, 06:17 PM
sorry could you be more specific?

what's ro production preset?

In render globals under quality I see a production setting, but that just seems to give me a fairly typical raytrace. Have been following Steven Tubbrit's MR tutorial to determine my settings and I am pretty happy with everything except for the dissappearing letters.

03 March 2004, 08:57 PM
Is your geometry using Bevel Plus, or made up of faces using many 5+ edges?

Mental Ray cannot render Bevel Plus because the front face uses a non sub-divided face.

Also your mesh might be non-manifold, use the CleanUp under Polygons, and read the documentation for all the attributes which might be useful to correcting the mesh.

As for the textures, bake to file texture if they're procedurals, and use only Off and Cubic for Filter type, Maya's MR doesn't support the other filtering techniques.

Maybe check the cameras Clip planes, 0.01 to 5000 is better if you've modeled objects largely.

Question: Does it render fine in Maya Software ?

03 March 2004, 12:04 AM
thanks for your reply,

there's a lot of good advice in there.

to answer your question, the model renders fine in software.

the textures weren't baked so that could have helped.

I did manage to get a satisfactory image by setting the render globals to production and then clicking final gather and global illumination on.

after comparing the two settings I noticed that having minSamples in Sampling Quality set to -2 (as per the S. Tubbrit tutorial) was causing the disappearing texture.

anyone know why this is so?


03 March 2004, 03:08 AM
It's mentalRay for Maya.. everything is dodgy ;)

But seriously, -2 is a very poor sample level, I wouldn't be suprised if things weren't taken into account, like textures etc.. though it screams of a bug. I test at -1 to 0 .. and final at 2,2.. not a big fan of adaptive AA, though my lighting level requires background objects to be crisp, darker scenes it's great.

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