Extreme samples needed to remove noise, diffuse shader Tweet

[sammie865]

Hi all,

Im having some trouble with a very basic scene. Its just a room, with 8 large lights in the ceiling( 80cm by 80cm), and one window.

All of the items I had in the room rendered clean at around 300-500 samples.
The problem is the walls. I have tried a glossy node, specular, diffuse and no luck with any of them, it takes over 8000 samples to get the noise on the walls to go away. Does anyone have any pointers or ideas as to whats going on here? im assuming its a problem with the lights but I have no clue as to what.

Here is a DL to the scene.
https://dl.dropboxusercontent.com/u/886 ... 20test.ocs
(right click and save link as)
The only way I have been able to get the noise to disappear is to render out over 12k samples.
Is there a way to reduce the noise any? im trying for an animation so im looking for a decent result at around 300-500 samples.
Or 2k samples for still renders.

Any ideas where the noise is coming from?
I have tried all kinds of settings on the lights, different sample rates, different light positions from the ceiling, adding IES maps. Im completely stumped as to why the walls have much noise.

Im aiming to use PT for the actual renders, but I have tried all of the direct light settings with no luck in removing the noise either. Tried PMC and for some reason PMC never cleans up, even at 12k there noise with PMC so that doesent seem to work at all.

Im using v1.2 with blender.

Any help is greatly appreciated!

Thanks,
sammie