Hi, I have posted again about the self illuminated material in mental ray and the issues that causes. When I have straight edges, I ve kinda shorted out the problem by adding skyportal with blackbody shader on. When I have organic shapes though that need to be like neon lights, serious issues appear. As you can see in the pictures attached, I have a ceiling that has a shape in the middle of it and hidden lighting inside that shape along its edges. Well, I can place many small skyportals everywhere, but the result isnt realistic. The other way is to make a spline at the shape of the the ceiling hole and assign to it SI material from arch+design mats, and check the “illuminates the scene when using fg” box. It doesnt provide complete accurate results though, but is way better than the skylights if only I could elliminate a serious problem; some weird blotches that appear underneath the geometry… It is like the light “pierces” the geometry or as if the geometry cant block the light that is being emmited.

I use Final Gather only with no GI. I dont know if this is a shader problem , a material problem or a lighting problem.

Help me out please. I ve seen lots of renderings with perfect hidden lighting on mental ray and I really dont know what to do. My client said he didnt like the light up there and I dont know what to do to change it.

Thank you!

3ds max 2010 x64 sp1 | Mental Ray

i7 920 @ 2.67GHz / ASUS P6T deluxe / 12GB RAM Corsair dominator DDR3 / ATI Radeon Sapphire 6950 HD 2Gb ram / Velociraptor 150GB 10000 rpm / OCZ vertex 2 SSD 60GB

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You will likely need to increase your Final Gather settings.  I’ve run into this several times before, and usually just fixed it in Photoshop. 

Attached are a few examples of a test scene using 3 lights, a red Self Illuminated renderable spline, and FG presets of Draft, Low and Medium with 2 bounces.  You can see how the edge bleeds pretty bad with Draft, but cleans up at Low settings.

3DS Max Design 2011 64-bit - Advantage Pack
Dell Precision T5500, Dual Six Core Xeon X5650 @ 2.67GHz, nVidia Quadro 5000, 24 GB RAM, Win 7 Enterprise 64-bit
Minneapolis, MN, USA

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Here it is. Take a look and tell me what might go wrong cause even with medium setting the problem remains. Thanx alot!

http://hotfile.com/dl/130523506/979a32e/SI_problem.rar.html

ps. thanx Steve thats why I couldnt attach my .rar

3ds max 2010 x64 sp1 | Mental Ray

i7 920 @ 2.67GHz / ASUS P6T deluxe / 12GB RAM Corsair dominator DDR3 / ATI Radeon Sapphire 6950 HD 2Gb ram / Velociraptor 150GB 10000 rpm / OCZ vertex 2 SSD 60GB

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si_problem.zip

My example was using FG only, no GI.  Unfortunately, I did not save the file.  But I did take a quick look at yours.  Your ceiling with the cutout is not a closed object, so I’d suggest adding a Shell modifier or something.  I’ve found that Max prefers closed objects, meaning there are no exposed back faces.  Also, I did a test with 4 bounces, and the noise mostly cleared up, and more of the red color bled out of the cove.  I think maybe you should revisit how you have that ceiling piece built, and create an actual cove where the light source would go, pretty much enclosing it except for one side.  This would be more realistic, and would force more light to bounce out. 

I don’t have a lot of time to play around with the file right now, but this might get you going in the right direction.

3DS Max Design 2011 64-bit - Advantage Pack
Dell Precision T5500, Dual Six Core Xeon X5650 @ 2.67GHz, nVidia Quadro 5000, 24 GB RAM, Win 7 Enterprise 64-bit
Minneapolis, MN, USA

Here is the new geometry which i closed the faces tell me if its better like this :)

3ds max 2010 x64 sp1 | Mental Ray

i7 920 @ 2.67GHz / ASUS P6T deluxe / 12GB RAM Corsair dominator DDR3 / ATI Radeon Sapphire 6950 HD 2Gb ram / Velociraptor 150GB 10000 rpm / OCZ vertex 2 SSD 60GB

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closed_geometry.zip