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Old 11-09-2012, 03:27 PM   #1
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alpha problem in Mental Ray for Maya

I am encountering a problem when trying to render a mib_glossy_reflection shader in maya, no matter what I do the object it's assigned to get's cut-out in the alpha as black.

I tried being smart and just assigning the output of this shader into the incandescence of a lambert and surface shader but that just caused a crash.

The attachment has an image to clarify.

I already tweaked everything around it, so I just need to find a way to fill the alpha of these objects with white. Anybody know how to do this ?
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File Type: jpg mib_glossy_reflection_alpha_problem.jpg (51.7 KB, 20 views)
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Old 11-09-2012, 03:43 PM   #2
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Did you try the "Pass custom alpha" checkbox in the renderglobals?
 
Old 11-09-2012, 06:08 PM   #3
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mib_glossy_reflection is also very much legacy. The mia_material_x_passes is the more modern alternative.
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Old 11-10-2012, 10:36 AM   #4
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Thanks Nookie,

I am having a hard time locating the pass custom alpha checkbox in the MR renderglobals.

I am using maya 2010
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Old 11-10-2012, 03:03 PM   #5
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It should be under "custom entities" but I am not sure about how and where it was on 2010. See if this image can help you
 
Old 11-10-2012, 07:43 PM   #6
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Hi Nooki,

Thanks for the quick response. I located the button and did a 2 test renders, one with the "pass surface color alpha channel" checked, and one unchecked.

Makes no difference.
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Old 11-13-2012, 09:16 PM   #7
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Use the mia_mat_x_passes instead.
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Old 11-15-2012, 09:55 AM   #8
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Yeah in the end I decided to indeed switch over to the mia materials, I was able to get pretty close to the original look, so it all worked out. Thanks for all the advice guys.

Cheers,

Arno
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Old 11-15-2012, 09:55 AM   #9
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