Hi everyone,

this is something that makes me go crazy: I can´t find the right setting for rendering my animations. I don´t want to use ambient occlusion, because it causes some ugly shadow artefacts which I can´t control. Somewhere I read, that you don´t need ambient occlusion, if you use indirect light. But when I use indirect light, I get this flicker on some places of some materials like you can see in the short, bad compressed, video.

Rendertest

Does someone know this problem and how to get rid of the flicker?

Here are my rendering settings:

Rendertest.png

Thanks for your help!!!!

This is a problem with Firefly as it takes guesses as to what the values are going to be. You could crank up the Indirect Lighting Quality, this will slow down the render because it has to take more samples per picture and make less guesses. You could drop the number of cores in your render settings to 1 as each core gets a different random number to base it's guess on. This means that you can not use the render queue (if you do) as each machine would also create a different random number. Also slows down the render. Unless you crank IDL quality to 100 it will still be a guess at some point. At 100 it will take forever as each point will be calculated instead of an average. SO your best bet would be to up the IDL quality to something you can live with.

Oh wow, I didn´t know about this random process. Thank you very much for the detailed description. I will try it out and post my render settings later.

Just one more question: Where can I drop the number of cores?

Edit menu - General Preferences - Render - change slider for number of threads (I think).

IIRC the Firefly sliders for Irradiance Caching and Indirect Light Quality work together. Higher ILQ = more rays; high IC = less guesswork. The higher they are the slower it goes. So, if one is higher the other can be lower. The more guessing IDL does the more blotchy artefacts but the faster it renders. It is a constant trade-off between quality and speed. The pre-pass with red dots is a good indicator - the more dots and the more densely packed, the higher the quality but the slower it will render.

As Richard60 says, you can turn off IC and brute force it, but the render speed becomes impractically slow. IDL does have occlusion built-in and it is better than AO because it takes account of light direction. If you render without IDL completely you could try playing with the Shadow Min Bias setting on the lights (in the Properties tab) - setting it lower than default can help with fine shadows but too low and polygons will self-shadow.

Thank you caisson! I´m still experimenting with some settings, which you and Richard60 suggested.

When I increase the IDL quality and use just one core for rendering the flicker gets a little better, but it´s not gone. I think I will usr AO instead of IDL for animations. I´ve just one problem: I always get those white edges as you can see in the red marked parts of the image below. I couldn´t figure out how to get rid of them so far. Does anyone know how to fix this?

Slight overlap of round things with flat things always does this. You can't completely get rid of it. However, decrease Min Shading Rate (which will increase render times) and also try reducing AO bias (which will eventually cause other artifacts). No values are universal - every situation requires tweaking. FireFly is just not automatic and all these knobs matter.

All right, I´ll try that, too. Thanks bagginsbill for your explanation.

Pinging for knowledge. Please continue.

I used these settings:

Min shading rate: 0.2 Bias in the Scene AO options: 0.001

That helped a lot! The white edges are almost gone. BUT: In the rendered animation I´ve got flicker on the skin of V4 and M4 and on the hair. So the search goes on.