View Full Version : instances flikering problem

04-26-2012, 04:59 AM
I'm rendering an animation of a landscape full of instances :5500 tree, 400 bushes.
Everything works fine except for a damm flikering in the instances.
As I have some experience on this I have tried all the tricks, but I can't fina a solution like I did with other tools like Hdinstances or kray in the past.

The trees are a simplified model from evermotion, same for bushes..

I tried to render without radiosity= no changes same flikering
I tired to switch off specularity and reflection from the leaves= no changes same flikering
I raised a lot AA like 4/32 and 0.03 of adaptive=no changes same flikering
I tired to avoid self shadow = no changes same flikering

Any suggestion?

04-26-2012, 05:15 AM
Id be tempted to say its the detail and AA, nothing to do with instancing itself. When detials, either from geo, textures, whatever else are rendering smaller than 1 pixel you will get flicker as these details traverse across the image from 1 pixel to the next.

The only solution is to up your AA, possibly quite a LOT.

Obv you dont want to go wasting AA samples all over the scene unnecessarily, so this is where doing a couple quick tests of AS comes in useful, to find the spot where AS is really only flagging up the problem areas for additional sampling.

04-26-2012, 05:32 AM
thanks for your reply.
I should say that I'm trying all the possible aa settings but i don't see any minimal change..

04-26-2012, 05:33 AM
Have you tried rendering 2 x the size (4 x the area) & then halving the size in Photoshop etc. Fine detail noise is easier to reduce this way.

Or even 3 x the size (9 x the area) if you are desperate. Worth a test.

04-26-2012, 05:35 AM
That amount of AA isn't a 'lot' it just might be high for what you want to do? :) Try by lowering your shading and shadowing sample quality to say 2 (to claw back some speed) and ncease the aa to 8 / 32 or 8 / 64. ( I have scenes with 16/128 if there's a lot of shader noise) I also find I have to use a much lower sampling threshold with LW 11, try 0.004 down to 0.002.

04-26-2012, 05:43 AM
Yeah... as tobian says, your settings arent going high enough... Id be aiming more toward x/128, x/256 for AA and 0.01 or lower for AS.

You basically need to throw LOTS and LOTS of additional AA samples at the problem areas.

04-26-2012, 05:45 AM
ok thanks!
I will try..
poor render time though, with radiosity even on my new esacore at 1280*720
time per frame will be drammatically high..

04-26-2012, 05:58 AM
Which is why I mention lowering the light and shading samples to as low as possible. The more aa samples you have the less shading samples you will need. and lower lighting samples will speed up the radiosity preprocess too. Do you have reflections in your scene, if so I have some tricks to remove them during the radiosity pass, which can dramatically speed up that portion of the render.

04-26-2012, 06:29 AM
it seem to work now..
with 8/64 and 0.01 of AS.
Yes I have reflection but not so much..
this is an old rendering but just to understand the situation

04-26-2012, 07:25 AM
I'd go lower than 0.01 - try 0.004, you just need more sensitivity with the new aa method than you did. In LW10 and lower I wouldn't go down much lower than 0.03 as it would kill my render times, it's much better now.