Mental Ray : GI colour bounce problem

[kjack]

Hi,

 

I am rendering the interior of a building which has a dark green marble flooring, with white walls, and roof.

 

I am using a daylight system using IES sun and sky. The scene is to scale and I've had to set the GI photons of the D-system to 20 to get an even spread of photons inside.

 

The problem is that the color of the floor is being bounced into the scene onto the walls and especially the roof, giving it a green tone.

 

I unlocked the photo tab in the materials (mental ray connections) and added a photon basic shader. I then added a greyscale version of the diffuse onto this. This fixed half the problem: the walls are fine but the roof still has a green tone.

 

Below is a test render on a different scene outlining the problem:

 

 

I have found articles mentioning a raytype switcher shader, but I cant find this in 3dsmax 2009.

 

I am really stuck here and any help would be very much appreciated.

 

Cheers,

[kjack]

poop, sorry guys, just saw the admin message about not posting mental ray threads here.

 

please accept my apologies, would appreciate if this could be moved to the right forum.

 

Apologies again.

[Dave Buckley]

have a look at jeff pattons blog, www.jeffpatton.net

 

you will find a lot of useful information about controlling colour bleed with mental ray and when using mental ray daylight system i always use mrsun and mrsky rather than IES sun and sky

[Dave Buckley]

http://jeffpatton.cgsociety.org/blog/archive/2008/1/

 

there you go, that should take you directly to the cblog entry about colour bleed rather than you searching through the masses of useful info (which i fully advise and encourage when you have time - it will teach you everything you need to know about MR)

[mattclinch]

firstly.. are you using a mrSun and mrSky in your Daylight system and not the default sun and sky?

 

...what do you mean by "I've had to set the GI photons of the D-system to 20"?

 

..also i don;t really understand "I unlocked the photo tab in the materials (mental ray connections) and added a photon basic shader". are you using arch + design materials? or pro materials in 2009?

[Dave Buckley]

he's using IES sun and sky i think matt,