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Caypiranha
08-19-2004, 03:39 PM
Hi there!

Ive got a problem with black spots in the picture under mental ray.
No mentalray specific stuff where used - and while using FG and GI
suuddenly these anoying spots appears. Working under Maya 6.0 /6.01.
So if anybody knows any solutions about these interesting phenomenon
- any feedback will be welcome...

thnx in advance!


http://nu-gfx.com/img/set_spots_2.jpg

Castiglion
08-19-2004, 03:53 PM
I have been struggling with these spots on my renders for quite awhile. See this thread: http://www.cgtalk.com/showthread.php?t=152737

It's something in the lights for sure. I have a strong suspicion it has to do with area lights not working with mental ray. When I get these spots, I delete all of my lights and rebuild them, as others have suggested to me, and the spots will go away UNTIL I ADD ANOTHER AREA LIGHT. Then the spots come back. On my last project, I just gave up trying to fight with them and waited until I was happy with everything else in the scene and then I rebuild the lights (sans the area lights) right before I rendered my animation. I was really hoping that this would be fixed in 6.0.1 but obviously it isn't.

Good luck!

slipknot66
08-19-2004, 04:54 PM
Dont use Maya default area lights, try to create a point light, and then convert into Mentalray area light, using a square projection,,or any projection you need:thumbsup:

Splin
08-19-2004, 05:08 PM
I think would be good idea to make that "black spot" issue as a sticky, delete ur lights...

slipknot66, is that a way to avoid them?

uschi
08-19-2004, 05:15 PM
thnx for all the hints ive tried the thing with mr_area lights and i got rid of all the artefacts (till now)... but i have the impression that it takes a bit longer to render

3DArchitecture
12-26-2005, 08:21 PM
Problem: Black spots appear in Mental Ray renderings.

Reason: Final Gather does not work with Multi/sub materials with Raytrace reflections that are "FACETED".

Solution: Turn "FACETED" OFF.

See 3DS MAX files attached.

http://www.3darchitecture.net/samples/Mental_Ray_BLACK_SPOTS_SOLUTION.zip

Kenneth Loyd

http://www.3darchitecture.net/samples/Mental_Ray_Simple_Test_(BLACK_SPOTS).jpg

http://www.3darchitecture.net/samples/Mental_Ray_Simple_Test_(NO_BLACK_SPOTS).jpg

Kenneth Loyd
3DArchitecture

floze
12-26-2005, 09:39 PM
Problem: Black spots appear in Mental Ray renderings.

Reason: Final Gather does not work with Multi/sub materials with Raytrace reflections that are "FACETED".

Solution: Turn "FACETED" OFF.

See 3DS MAX files attached.

http://www.3darchitecture.net/samples/Mental_Ray_BLACK_SPOTS_SOLUTION.zip

Kenneth Loyd

http://www.3darchitecture.net/samples/Mental_Ray_Simple_Test_(BLACK_SPOTS).jpg

http://www.3darchitecture.net/samples/Mental_Ray_Simple_Test_(NO_BLACK_SPOTS).jpg

Kenneth Loyd
3DArchitecture
Not quite sure what faceted means (3dsmax times long time ago.. sigh..), but the black spots have different causes mostly. Sometimes it's happening because of the light shaders, sometimes because of normal setting shaders (bump), sometimes because of layering/mixing shaders... there's no general fix to this I guess. Thanks though. ;)

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