Color bleeding

Ivan_m · May 25th, 2008

I have a problem with mental ray. When I render my building I get nasty places with color bleeding. I've tried with photon base shader in the photon slot of the material, but it didn't work. Any suggestions? I've used max 2008. Any suggestions?

SandmanNinja · May 25th, 2008

Can you post a render? It would help with the answer.

And I'm sure Brian Bradley knows! He's a Mental Ray guru!

Ivan_m · May 25th, 2008

Thanks for the replay. I'll post a image with the problem as sooner as I can.

In this one you may see the color bleeding and the reason - the grass:

In this one the grass is removed:

The reason I don't like using MR is exactly because of the color bleed it creates. :/

Justin Hunt · May 25th, 2008

colour bleed can be controled either by droping the "Diffuse Level" or using the material over-ride for FG calculation and the proper material for the frozen FG, final render.

With max2009 you have the option now for objects not to react to FG.

jhv

pixelperfectg · May 25th, 2008

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

Brian Bradley · May 25th, 2008

Hi Ivan,

Both Justin and Jeff have given enough info to get
colour bleed to work how you want.
To be honest mental Ray works as it should when it
comes to colour bleed. If you fed the same light energy
and colour saturation into a 'real world' set up, then the
results would be pretty much the same. The trick is to
understand how colour is transfered between surfaces
by the transport of light energy, and then understand
the toolset in MR that allows you to control that process.

Regards
Bri

kris McIsaac · May 25th, 2008

One thing to remember is that in real life grass is not a flat plane. It is thousands of blades at thousands of angles and slightly transparent so not all the light is thrown back up onto the surrounding objects. Like it was mentioned, reduce the diffuse colour to reduce the amount of green bounce.

Ivan_m · May 26th, 2008

Thank for the help and for the attention.

It helped me a lot.
About the grass - in the final render I will use a displace map for sure.

May 25th, 2008	#1 (permalink)
Ivan_m Junior Member Join Date: Feb 2008 Location: Blagoevgrad Age: 20 Posts: 26 Name: Ivan Mitov	Color bleeding I have a problem with mental ray. When I render my building I get nasty places with color bleeding. I've tried with photon base shader in the photon slot of the material, but it didn't work. Any suggestions? I've used max 2008. Any suggestions?

May 25th, 2008	#2 (permalink)
SandmanNinja Moderator Join Date: Mar 2007 Location: Ballarat, Victoria, Australia Posts: 1,375 Name: Joel Callahan	Re: Color bleeding Can you post a render? It would help with the answer. And I'm sure Brian Bradley knows! He's a Mental Ray guru! __________________ -SandmanNinja website

May 25th, 2008	#3 (permalink)
Ivan_m Junior Member Join Date: Feb 2008 Location: Blagoevgrad Age: 20 Posts: 26 Name: Ivan Mitov	Re: Color bleeding Thanks for the replay. I'll post a image with the problem as sooner as I can. In this one you may see the color bleeding and the reason - the grass: In this one the grass is removed: The reason I don't like using MR is exactly because of the color bleed it creates. :/ Last edited by Ivan_m; May 25th, 2008 at 02:20 PM.

May 25th, 2008	#4 (permalink)
Justin Hunt Veteran Member Join Date: Jan 2005 Location: Brisbane Age: 33 Posts: 1,366 Name: Justin Hunt	Re: Color bleeding colour bleed can be controled either by droping the "Diffuse Level" or using the material over-ride for FG calculation and the proper material for the frozen FG, final render. With max2009 you have the option now for objects not to react to FG. jhv

May 25th, 2008	#5 (permalink)
pixelperfectg Senior Member Join Date: Dec 2003 Location: SC, USA Age: 38 Posts: 206 Name: Jeff Patton	Re: Color bleeding http://jeffpatton.cgsociety.org/blog/archive/2008/1/ __________________ Jeff Patton My mental ray blog \| Personal Website \| mrmaterials.com

May 25th, 2008	#6 (permalink)
Brian Bradley Senior Member Join Date: Sep 2005 Location: Greater Manchester Age: 43 Posts: 422 Name: Brian Bradley	Re: Color bleeding Hi Ivan, Both Justin and Jeff have given enough info to get colour bleed to work how you want. To be honest mental Ray works as it should when it comes to colour bleed. If you fed the same light energy and colour saturation into a 'real world' set up, then the results would be pretty much the same. The trick is to understand how colour is transfered between surfaces by the transport of light energy, and then understand the toolset in MR that allows you to control that process. Regards Bri __________________ 3Ds Max - Mental Ray - VRay - Brazil Training Modules www.mentalboutmax.co.uk The MBM Blog www.mentalboutmax.blogspot.com Vray Learning Resource www.vrayelite.com

May 25th, 2008	#7 (permalink)
kris McIsaac Member Join Date: May 2007 Location: Melbourne Posts: 51 Name: Kris McIsaac	Re: Color bleeding One thing to remember is that in real life grass is not a flat plane. It is thousands of blades at thousands of angles and slightly transparent so not all the light is thrown back up onto the surrounding objects. Like it was mentioned, reduce the diffuse colour to reduce the amount of green bounce.

May 26th, 2008	#8 (permalink)
Ivan_m Junior Member Join Date: Feb 2008 Location: Blagoevgrad Age: 20 Posts: 26 Name: Ivan Mitov	Re: Color bleeding Thank for the help and for the attention. It helped me a lot. About the grass - in the final render I will use a displace map for sure.

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