Light Bleed in 3DSMax/Vray

[thomascoote]

Hi,

 

Wondering if someone can help me with something that has me scratching my head.

 

I have a scene I've started modelling, for some reason I'm getting bad light bleed in one area that I can't seem to get rid of.

 

 

This was a render I cancelled in the irradiance map calcs, but you can see what I mean here. There is a recess in the wall, where I am trying to place a set of kitchen units. I am leaving a small space at the top and sides, as that is what my reference shows, however, whenever any geometry is placed in this recess with a small gap between itself and the walls, I get a bright light bleed as shown above. Delete the geometry, it goes.

 

I can't figure this out. I've tried with extremely high irradiance map settings, I've tried with Brute Force, I just have no idea what could be causing this. The geometry is clean, and the units you see in there are just a standard box with no modifiers on.

 

Does anyone have any idea? I'm losing my mind here.

 

Thanks,

[Chris MacDonald]

Do your external walls have a thickness?

[thomascoote]

Do your external walls have a thickness?

 

Yes, they were originally extruded splines, but I put a shell on top and I still seem to have a problem. I'm going to try modelling the walls again from scratch as an editable poly later on tonight and see if that helps.

[inpow watir]

You need more samples in your setting. Try to bump up subdivs

[thomascoote]

You need more samples in your setting. Try to bump up subdivs

 

Bumped up every single setting that could be bumped up. Made no difference at all. Bumped them up to insanely high settings aswell, also no difference.

[Francisco Penaloza]

First check your geometry, be sure all vertex are welded and there is no gap. Shell modifier usually help here, but you already tried that.

Second check your normal.

be sure to not use pure white in your materials a 180 or so value will do fine.

Reset all your V-Ray settings, then change your GI to brute force first and second bounce, and check your image, if that bright area is gone, then you know it is GI related.

LC has problem with tight spaces, you may want to try a real world scale instead of pixels, small size and more dense, but in any interior 2000 is already more than enough. ALso medium IRR with detail enhancement can help you here too.

Also wait until the render is done, sometimes the pre-pass look brighter than when it render

[thomascoote]

First check your geometry, be sure all vertex are welded and there is no gap. Shell modifier usually help here, but you already tried that.

Second check your normal.

be sure to not use pure white in your materials a 180 or so value will do fine.

Reset all your V-Ray settings, then change your GI to brute force first and second bounce, and check your image, if that bright area is gone, then you know it is GI related.

LC has problem with tight spaces, you may want to try a real world scale instead of pixels, small size and more dense, but in any interior 2000 is already more than enough. ALso medium IRR with detail enhancement can help you here too.

Also wait until the render is done, sometimes the pre-pass look brighter than when it render

Thanks for all of that, I will be checking it out and will post back with an update!

 

Ahh I was so stressed at this point I just cancelled it and screengrabbed it anyway Its still there in final render lol

[frog_a_lot]

Post your settings.. IR/LC settings, Render size, sample size, DMC etc etc

[thomascoote]

First check your geometry, be sure all vertex are welded and there is no gap. Shell modifier usually help here, but you already tried that.

Second check your normal.

be sure to not use pure white in your materials a 180 or so value will do fine.

Reset all your V-Ray settings, then change your GI to brute force first and second bounce, and check your image, if that bright area is gone, then you know it is GI related.

LC has problem with tight spaces, you may want to try a real world scale instead of pixels, small size and more dense, but in any interior 2000 is already more than enough. ALso medium IRR with detail enhancement can help you here too.

Also wait until the render is done, sometimes the pre-pass look brighter than when it render

 

Thank you for this advice.

 

I swapped and changed my primary and secondary GI around a few times to try to isolate whether it was a GI issue or a geometry issue. I found that regardless of combinations, if I used light cache as my secondary I would get the leaks, but no leaks when not using it.

 

It turned out to be having the retrace parameter unchecked. As soon as I checked it, the light leak is completely gone. Going to have a read up on the retrace parameter now.

 

Thanks for the help!

[gabrielhildebrand]

Thank you for this advice.

 

I swapped and changed my primary and secondary GI around a few times to try to isolate whether it was a GI issue or a geometry issue. I found that regardless of combinations, if I used light cache as my secondary I would get the leaks, but no leaks when not using it.

 

It turned out to be having the retrace parameter unchecked. As soon as I checked it, the light leak is completely gone. Going to have a read up on the retrace parameter now.

 

Thanks for the help!

 

Quick question. Did you mean the "use retrace threshold"? Did you change the threshold or just activated it?

[thomascoote]

Hi,

 

Under Light cache settings there's a tick box caled "Retrace"

 

I can't remember what I changed it to, but I believe I just lowered the threshold until the problem was solved.

[gabrielhildebrand]

Nice thanks! I play around with the threshold. cheers