Light emitting ceiling problem

[danjames]

Hello.

New here and not sure if I'm posting in the correct place.

 

I did some architectural rendering at uni and now trying to re-learn, develop and build a portfolio with the aim of doing it as a career.

 

I've encountered a problem I can't fix with the ceiling seeming to emit light.

 

http://i.cubeupload.com/rmrfUl.jpg

 

This is exactly the same model and setting but with the ceiling moved higher in the scene.

 

http://i.cubeupload.com/wIXtxQ.jpg

 

I can't really continue any work until I know what the issue here is, so any help would be appreciated.

[Corey Beaulieu]

Seems like a light leak from low settings. I think it goes away when you move the ceiling higher because it is no longer in view and thus largely not calculated. If you try shelling the walls and ceiling (I'm assuming they are planes) and/or just up the settings, I would imagine the problem will resolve itself.

 

That said, I would straighten your camera, lower your F-Stop, and put your materials bump/reflection back in order.

[Nicolai Bongard]

Another way to fix it fi the walls and ceiling are planes; you could attach them, select the corner verteces and weld them, set the ceiling to have a different material ID, and apply a multisub material. That way you can make sure there are no leaks. If it still looks weird in your renders, you should have a look at your render settings as Corey suggested.

[danjames]

Thanks for the help so far.

I've narrowed the problem down to being something to do with global illumination, as it only occurs when enabled.

 

Here's a quick render of the scene without GI:

http://i.cubeupload.com/2V7UNp.jpg

 

And with:

http://i.cubeupload.com/fNeI3a.jpg

 

Any ideas why that could be happening?

Increasing the render settings didn't resolve anything and the walls, floor and ceiling are boxes rather than planes.