Holes in the plane object?

[AndyWelder]

I tried to mimic a thin roof  by adding an image shader to the surface of a plane object. This looks OK when viewed from a distance but the moment there's a light source underneath it the roof looks like a sieve with light shining trough countless holes.
At first I thought the displacement was punching holes in the plane but unchecking the displacement didn't help.
AA at seven didn't make a difference either.
Is there something that can be done about it? Or is what I want to achieve impossible because of the particular properties of the plane object?

[j meyer]

Hi,
could be similar to what was discussed here
http://forums.planetside.co.uk/index.php?topic=3215.0
Hope you'll find something helpful,J.

[dandelO]

Hi, Andy. This is a problem with the lightsource object, not the plane. There is a problem that makes lightsources exceptionally grainy, it doesn't happen with sunlights, though you can't place a sun so close to the camera. I think it needs to be in the extremities of your scene, given that there are no transform controls for it. Dragging the sunlight's transform arrows won't help either.

Enabling ray-traced atmo' and bumping samples up to the heavens(I mean really high, not just the 64-128 samples that you'd normal get away with for grainy scenes, I've still suffered this problem with samples of 256 and higher when using lights) can help this but that will REALLY eat up render time.
I rarely use lightsources for this reason, I just can't justify the render time.

EDIT: Ahh, Mr. Meyer, you beat me to it.

[AndyWelder]

Thank you, guys. Now that I know what caused the problem I think I have a solution: I've added a small plane (black, just to be sure ) right above each light source and with the ray traced atmo it looks like the problem is solved, the partial render now going on doesn't show the "holes" yet. Render times are way up but hey, anything for the good cause!

[dandelO]

You could probably just render the ray-traced crop and post it into the original render. Save a LOT of time.