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TheGrandMaster1
04-13-2006, 03:57 PM
Time to call in the cavalry.
I seem to have a problem with black materials when using global illumination. They lose their specularity and shininess, and detail when using the skylight, global illumination, and mental ray, despite this way being much more realistic for anything else. When rendered standard, or with regular lights of no global illumination, they, whole not looking very realistic, keep at least the shininess and detail. See, check it out.

http://web.ics.purdue.edu/%7Emjschwei/images/cameranormal.jpg

While not being realistic, the black materials keeps detail and highlights.

http://web.ics.purdue.edu/%7Emjschwei/images/cameraskylight.jpg

It looks like itís made of black construction paper or something. I have a similar problem with the black pieces of my chess set. Any dark material, the detail is lost, and you can basically see the outline of a black silhouette for the black pieces. Shininess is also gone. :(

http://web.ics.purdue.edu/%7Emjschwei/images/chessexample.jpg

Wondering how to get nice realistic renders of black materials (plastic/wood/shiny) with global illumination, hopefully a technique that would work in both mental ray and Vray. Thanks.

CapnPanic
04-13-2006, 06:14 PM
When you stop using point/default lights, and switch to the GI skylight, then the specularity goes away with it. Since the GI doesn't have a point source, there is no way to create the specular highlight.
What you should do is add a reflective element to your materials and put some overbright white cards into your scene, for the camera to reflect. That will give you back your highlights, and still allow you to use the GI. Alternatively, if you don't want to use reflections, you can add some spot lights to your scene and set them to only affect specular. That will allow them to not brighten up your scene, but just add the specular highlights.

TiskO
04-14-2006, 04:35 AM
Glossy reflections! Hooray for glossy reflections! :D

TheGrandMaster1
04-14-2006, 02:54 PM
When you stop using point/default lights, and switch to the GI skylight, then the specularity goes away with it. Since the GI doesn't have a point source, there is no way to create the specular highlight.
What you should do is add a reflective element to your materials and put some overbright white cards into your scene, for the camera to reflect. That will give you back your highlights, and still allow you to use the GI. Alternatively, if you don't want to use reflections, you can add some spot lights to your scene and set them to only affect specular. That will allow them to not brighten up your scene, but just add the specular highlights.

Thanks Panic, that was the most thorough and helpful answer I've got out of two forums. I"ll give this a try.

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04-14-2006, 02:54 PM
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