arg. Flicker in Animation

Hey guys, anyone know what is up with the flickering? I made an anim of a character, and the ground kind of flickers between dark and light toward the back edge. I think it’s related to AO, and I vaguely recall seeing it before. The normals are all fine.
I’ll throw up the file if anyone needs a look. I’m going to go try a couple more things with it.

does the entire floor flicker? or just the edge? If your camera is moving relative to the floor, i have a few explainations:

  1. AO sample not high enough
  2. AA sample not high enough
  3. high frequency texture? (Not enough MIP mapping if its an iamge?)
  4. z-fighting? maybe you have two floors overlapping each other by accident.

I am assuming you know how to recognize each of these aforementioned problems and fix it. judging from your post count (yes i know…i shouldn’t. But i am being lazy)

yeah, i should have mentioned, the camera isn’t moving at all. i initially had the AO samples at 8, but i cranked them down after the flickering began. i’ll try cranking them up to 12 and see if that does anything. what is AA btw? I’ll try turning off the non procedural ground texture and see if that does anything too. Anyway, if that doesn’t cure it, I’ll throw the file up.


What you can do, instead of turning up AO to 12 and wait an eternity for a single picture, you can just turn it off and see if it still flickers. :slight_smile:

You can help image texture flickering by a) turning up the ‘filter’ in texture buttons or b) turning on full OSA for that material (slow!).

For the AO, try also seeing how low you can get away with making the ‘Dist’ value. The lower it is, the faster and more efficient, but can make the effect less noticeable. It’s worth a try.

Also, if you’re using AO set to both add and subtract, without many other lights, the flickering effect will be much more intense since most of the lighting is coming from the AO. It’s much better (and better looking) to light a scene properly with AO off, then on top of that use AO set to subtract, in order to get the occlusion shadows.

Hm, we really need a nice ‘optimising your render’ tutorial in the blender docs…

ah, i finally found the problem. the flickering was being caused by a shadeless background ‘sillouette’ object, and by turning off ‘tracable’ and other shadow related settings it has been fixed. Thanks for your help, guys, and broken, that’s a good idea, especially with the new types of sampling.