Light Leak?

[landrvr1]

I've got a wall mounted light fixture in a scene and I'm getting some strange light leak going on at the bottom of the fixture with my current settings. When I set the min/max rate under Irradiance Map to both zero, the problem goes away but the rendertimes go up. Any suggestions as to how I might fix this without taking a hit on the times? Tnx

 

 

 

 

 

 

[landrvr1]

bumpity!

[cg_Butler]

I think you should increase your IR settings. Have you tried rendering on high to see if the light leak is reduced? Is your light fixture is definitely touching the wall or even going in to the wall? You can also turn on Check sample visibility to see if that helps.

 

What is your render time? Usually, the only way to get rid of these problems is to have higher render settings!

[Scott Schroeder]

I looks like your fixture is bouncing GI onto the wall. Usually white objects that close to a wall with light source inside will generate some bounce. Try just turning the generate GI off in your light fixture. Something that small won't affect your scene if it is not generating GI samples and it helps with your contact shadows.

 

Also, make sure you have no 255 whites in your materials or lights.

[Tommy L]

 

Also, make sure you have no 255 whites in your materials or lights.

 

Is that really true? I've never tested it....just heard someone say they'd heard it from Chris Nicols.

[Scott Schroeder]

Is that really true? I've never tested it....just heard someone say they'd heard it from Chris Nicols.

 

I've scene 255 whites blow up a scene before.

 

255 whites with linear color mapping, even if you have clamp output and sub pixel mapping on, can cause strange things in your scene. They tend to bounce incorrect GI if it's near another object like a light fixture on the wall. It's not all the time, but I've been burned before to just use 250 whites or less. I think if you are using anything other than linear color mapping, the risk is less. It may drop even more if you aren't using exposure either.

 

Is it a steadfast rule? I don't know. I avoid it just because I don't want it to blow during a last minute render.

[landrvr1]

Tnx gents. Really what was needed was an overall bump in the IR to medium. I was hoping I could do a simple one setting tweak, but that didn't cut it...

 

Also, changing the white from 255 (which is exactly what it was...) had no effect in this case. But that doesn't mean anything because that rule - like so many others - are very dependent on a million other things.

[cg_Butler]

Glad you got it sorted. Light leaks can be caused by a lot of things and all suggestions in this thread should be the first options to look at. Starting with increasing the IR and LC settings!

 

Enjoy. :-)

[bilderbaurendering]

hi, have you tried Retrace Threshold under the LC ? sometimes it helps to get rid of leaking lights. give it try.

[Chris MacDonald]

I also find the "detail enhance" often cleans up any light leaks that I get.