I've asked this before but nothing that was suggested worked for me so I thought I'd ask again a year or so later to see if there's any fresh wisdom in the group.  You can see the flicker in the sample.

I get this flicker on lighting I've set up myse4lf and some of the presets that come with iClone. Having tried everything I've been able to think of and given that I've never really seen that flicker in other people's renders, could this by a graphics card issue? I'm using an 8gb GTX1080. Alternatively, could it be something to do with the hair mesh the light is shining through? In this case DAZ Riley Hair but I do get that same flicker with hair I've purchased from the RL store.

I'm getting to the point where I need to be properly lighting and outputting my short film but I just can't figure out why the flicker is there. Some scenes do it, some scenes don't. The sample is lit with a single spotlight and using IBL as a fill - but it does that no matter what light type or visual/render setting I choose.

All suggestions welcome - even the basic ones because you never know, I might just be doing something stupid.. 




Jeff Kirkland | Director • Cinematographer • Storyteller
Hobart • Tasmania • www.one18films.com
SYSTEM: AMD Ryzen 5 5500 | 32gb RAM | RTX 3060 12gb | 1tb SSD System | 44tb HDD Storage

So...."Shadow Resolution" setting is high? And "Suppress Shadow Flicker" is on? And it still flickers?


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And if you disable hair physics and remove her animation (but leave camera movement) would flickering stop?

Shadow resolution in that example was 2048 but setting the resolution to high makes the flickering blocks smaller but still easily seen. Turning anti-aliasing on also helps but never eliminates it. Suppress shadow flicker makes no difference.

To try and figure this out I've changed every setting I can think of, one at a time, and nothing stops the flicker short of starting over and lighting differently (and keeping my fingers crossed it doesn't happen again).



Jeff Kirkland | Director • Cinematographer • Storyteller
Hobart • Tasmania • www.one18films.com
SYSTEM: AMD Ryzen 5 5500 | 32gb RAM | RTX 3060 12gb | 1tb SSD System | 44tb HDD Storage

I get the same flicker whether hair physics is enabled or disabled. I've not tried testing with the animation removed (if that was the cause, it'd make it tough to make an animated film) but I'll test that when I get back to my office. I suspect the answer will be that it's fine though as the shadow won't be redrawing every frame. 

Right now my gut feeling is either that things like strands of her hair are casting really fine shadows that the renderer isn't coping with, or it's something hardware/driver related.


Jeff Kirkland | Director • Cinematographer • Storyteller
Hobart • Tasmania • www.one18films.com
SYSTEM: AMD Ryzen 5 5500 | 32gb RAM | RTX 3060 12gb | 1tb SSD System | 44tb HDD Storage

I got to the office and realized I hadn't saved the demo file so I had to quickly recreate it.  As expected, removing the animation stopped the flickering. Disabling the physics made no difference. I also replaced the hair and while the flickering was better, it still wasn't gone.

I've attached two new videos, the first being the hair with no physics, the second being with different hair but you can still see the flicker, especially down on her chest.

EDIT: On YouTube the alt hair version doesn't look as bad as it does playing back the rendered file on my screen here.

Thanks for taking a look...






Jeff Kirkland | Director • Cinematographer • Storyteller
Hobart • Tasmania • www.one18films.com
SYSTEM: AMD Ryzen 5 5500 | 32gb RAM | RTX 3060 12gb | 1tb SSD System | 44tb HDD Storage

 As expected, removing the animation stopped the flickering.

That is what I wanted to hear.
So yes, it is not your hardware or corruption of some sort. It is normal for iClone shadow system.
The second clip looks better because hair bunches/strands are less transparent than hair in the first video.

iClone has hard time rendering low resolution shadows through fluctuating (because she moves relatively to the light source) transparency such as hair.
The shadow resolution would make some difference. But again, as I mentioned in the other thread, light distance is a key factor.
2048 Shadow resolution from a distant light would look different, than same shadow resolution from a closeup light.

So disable shadow from a distant Spot Light.
Create Spot Shadow at the same line of sight as the existed Spot Light, but bring it closer to the face.
Play with range/angle/shadow resolution.
If it does not make much difference, then play with viewer perception. Make them accept flickering as normal!

The hair in your render is mostly static (even the first one where physics was enabled).
It is indeed looks very odd - static hair and flickering shadow behind it.

She appears to be outside. So animate hair with the wind. Make it move! Then flickering would seem normal to the viewer.
And also draw viewer attention to something else - highlights, like "wet" eyes, back light reflection moves through the hair... something that would draw attention away from stupid flickers :)

This is highly transparent hair - specially in the front. Can you claim that shadow is flickering here?

Being a cinematographer/editor/colorist for a living, I've got a keen eye for even a lone pixel misbehaving in a single frame of footage but while I can see an extremely small amount of crawl in there it's not enough that I'd be unhappy with the result. Certainly, I could probably fix what's there with some noise reduction in post.

My biggest concern is that what's subtle on a computer monitor is going to stand out like a neon sign when projected on a cinema screen.

Anyway, thanks for the tips - they're much appreciated. I'll try everything you've mentioned and see if I come up with a winning formula. 

Jeff Kirkland | Director • Cinematographer • Storyteller
Hobart • Tasmania • www.one18films.com
SYSTEM: AMD Ryzen 5 5500 | 32gb RAM | RTX 3060 12gb | 1tb SSD System | 44tb HDD Storage

Good Luck, keep us posted!

Is PCSS enabled under the Light tab? If so, adjusting the Softness value may help.
Is TAA checked under the Project tab?



Click here to go to my YouTube Channel filled with iClone Tutes and Silly Stuff

Visit ANIMATED PROJECTIONS Powered by iCLONE

Intel Core i7 3960X @ 3300MHz Overclocked to 4999.7 MHz Sandy Bridge 24.0GB DDR3 @ 833MHz Graphic Display HP ZR30w 
GeForce GTX 980Ti 6GB  Microsoft Windows 7 Professional 64-bit SP1 ASUSTeK COMPUTER INC. P9X79 WS (LGA2011)