Weird light bleed

[andyH]

I am working through a texure and render challenge for a dining room and on my initial light tests I am getting some weird light burn where my tablecloth rests against the chair at the head of the table, see attached image. Its as if the photons get stuck in the crease and rattle around causing light where there should be shadow.

 

Anyone know what I should be doing to reduce or eliminate this problem?

 

The scene is lit using a daylight system using mr sun and sky. There are no sky portals over the windows on the right of the scene.

 

Render setting are: High FG, GI optimized for FG, Mitchel filter and anti-aliasing 1/16. mr Exposure control using the interior daylight preset but one stop faster on the shutter at 1/32, Gama/LTU enabled.

 

I have tried changing textures on the tablecloth and chair, and have increased the sample radius but still get the same problem. I am fairly sure its a GI issue as when I turn off GI the very dark render shows no indication of the burn, if thats what you call it.

 

I know I could probably fix it in post, but I would rather optimize the render settings to get rid of this type of thing before considering post as the fix.

 

Many thanks,

[Justin Hunt]

Am I understanding you correctly are you using Photons as well as FG ir just FG?

 

Is the cloth single sided?

 

Photons dont like single sided objects, especially if they intersect other objects. Try shelling it to give it a bit of thickness.

 

jhv

[andyH]

Am I understanding you correctly are you using Photons as well as FG ir just FG?

 

Is the cloth single sided?

 

Photons dont like single sided objects, especially if they intersect other objects. Try shelling it to give it a bit of thickness.

 

jhv

 

You know as I was posting this it actually occured to me that it may be because it is single sided. And it is, I havent had a chance to use a shell modifier on the cloth yet, but when I get home this evening I will give it a go.

 

I am using FG and GI. Although I admit I still dont fully understand what all the settings do, I had always thought this combination gave the best results for interior scenes?

 

I am still trying to establish my method, so far it seems that doing most of the modelling first and then applying base or standard textures and then getting the light as close as you can to what you want, then applying the proper textures and if necessary adjusting the light for final render. Would you agree that is a good workflow?

 

Anyway, thanks for the advice, I will shell the cloth and see how it looks.

[TheAllusionisst]

Hey, just posted at 3DA on this as well. Since the other chairs to table cloth aren't doing this, I would first try to move the chair back slightly so that geometries don't actually intersect (if they do now) and if that fails, Justin's advice on double sided materials or shell modifier would be good to try next.