Mental Ray Self Illuminated Material Problem

#1

I’m trying to create a reception counter with a recessed light, with the light washing down the front of the counter. There is a lip in the counter which hides the light.

My problem is that i’m using an Arch & Design self illuminated material to provide the lighting, but the light spills over the top of the lip which hides the light.

http://i1114.photobucket.com/albums/k522/Andy_MacRae/MentalRaySelfIlluminatedLightProblem.jpg

I’ve used a cylinder, which i’ve hidden from camera. Any help would be appreciated.

Im using 3ds Max 2011 & there aren’t any lens effects in the scene.

#2

That’s odd. Maybe your final gather settings aren’t high enough? Try increasing the quality of the FG and see if the situation improves.

#3

It’s currently set to low, but will try upping i when I’m back on it tomorrow. Cheers

#4

Are you using a glow post effect? To me, it looks like all the red light is simply a result of a glow and not actual light being cast. But it’s kind of blurry, so it’s hard to tell.

#5

There’s no post effect happening. The red glow is because I was trying to achieve a red light, but to make the washing light visible I’ve had to crank the luminance physical units up to 100000, which makes the light more white than red.

My exposure is set at 7.5.

#6

I’ve tried changing the final gather settings, but no luck…

http://i1114.photobucket.com/albums/k522/Andy_MacRae/MentalRaySelfIlluminatedLightProblem01.jpg

The problem is still there, but the light is has a harder ‘edge’ :sad:

#7

u can check if the material for the counter has some translucency…may be thats causing some scattering within the material…

#8

Oh, so the room is awash with light from a mental ray daylight system? The first things I would mention would be either a scale problem or a units problem, or both. I’ve had similar things happen from time to time.

For one, try turning off your daylight system and adjusting your exposure, so that you only have this one light. Adjust the light back to a more normal amount and adjust the exposure accordingly.

Can you show your exposure settings and material settings?

#9

I’ve attached two files where I’ve tried to replicate your problem. It does seem to have something to do with the final gather interpolation. If I go with the default “Interpolate over Num. FG Points” value (30), I get some light leaking around, but not too bad. When I up that to 100, it gets pretty bad, like my attachment. If I lower Interpolate to 1 (no interpolation), the problem goes away, but looks terrible without the interpolation.

Another way to resolve the problem is by switching the FG Point Interpolation to Radius Interpolation Method and selecting a radius value that prevents the interpolation from selecting FG points inside the recessed area.

Both of these seem like pretty bad hacks, though, does anyone know the correct way to solve this?

#10

Thanks KevinGeorge,

I’ve attached my exposure settings & ‘light’ material settings. I’ve created a simpler scene & tried playing about with some of the settings in FG, but it always looks bad. The best its looked is with the ‘use radius interpolation’.

Hopefully you can see something in my settings that will answer the issue.

http://i1114.photobucket.com/albums/k522/Andy_MacRae/LightMaterial.jpg
http://i1114.photobucket.com/albums/k522/Andy_MacRae/Exposure.jpg


#11

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