Displacement flickering in animation. Any advice?

[gonzilla]

I'm having a strong flickering in displaced surfaces, as in this grass and rock example. Any clue?

http://www.akenar.com/DisplacementFlickering.avi

[sk_fly]

You probably need more sampling, you're geometry is very thin. Try turning you threshold under adapive sampling down to .05 or even lower. Also try turning on your normals, and play with that value. Right now you are only doing the object outline, it the grass is all made out of one object with displacement then you want to sample along its normal as well.

If that doesn't help you may need to turn you min rate to 1 and max 3. If you have to due the I suggest rending the grass by itself and compositing the image back together so you don't have to render the entire thing at such a high rate.

[sk_fly]

Also try turning off your GI, if it still flickers it is definatly coming from the displacement. Try another test with you GI on and no displacement to see if it flickers. It could be the GI or the combo of GI and displacement, you may need more samples in your GI as well as more AA samples.

[RErender]

It is almost certainly the GI, I have been lighting the grass seperately in my animations.

[gonzilla]

Thanks to all. I have displacement in the rock, and the shadow under the tree is flickering too. I'm afraid the rendering times are too high with your parameters. I'm in a tight deadline and I think i will simplify the scene if there aren't other solutions.