View Full Version : Fiber FX Rendering Issues

12-10-2013, 10:13 PM
For the life if me i can not figure out why i am getting this flickering in my fur. I have the fur looking great for our test but when i render it's flickering on every frame. I do not have radiosity on so it can't be a cache thing. I've played with all the geometry settings.. thickness.. Scales.. render settings.. nothing gets it smoothed out. I've lowered the density and it helped a slight bit but to low and you can see the model. Has any one seen this or had the issue? I'm so close to really having this looking good but just missing that last piece..

Here's a link to what i'm seeing


I can post a .zip of the scene if anyone is interested in helping


12-10-2013, 11:22 PM
What version of LW are you using? FFX has had a lot of revisions to it, so if you're using an older version of LW you'll be missing out there. Also, what type of shadows are you using? Point Sample tends to give the best results, you could try upping Sample Radius, Multi Sample and shadow depth values to sort it out (Altering one value at a time of course :) )

12-11-2013, 12:56 AM
I can think of a few reasons for FiberFX flicker.

1. Shadow Density--if you have it set too low, it will almost certainly flicker.

2. Subsample Lights--FiberFX isn't optimized for Subsample Lights like Dome or DP Infinite--it works but it hits a quality threshold at around 20, which might not be high enough in many situations. If you look at my 'B2' excerpt (http://vimeo.com/68543424), you can see this result--the fur flickers a little because I'm using Dome light in many of the shots for the cat's. I was able to minimize it by processing the fur layer with RE:Vision FX DE:Noise in Fusion. LW3DG is aware of the problem and I think they're looking into it.

3. LWSN -2--this might be fixed now but I had some flicker issues with it in BNR many months ago. This kind of flicker looks different though--it's more like inconsistent fiber placement rather than shadow flicker. Another user tested my shots for me under LWSN -3 and the results were better. At the time, I had issues using LWSN -3 with BNR but I think this has since been fixed. (Sorry, I a bit behind in my testing these days.)

From looking at your video clip, I'm guessing the problem might be related to 1 or 2.

Hope this helps.


12-11-2013, 12:56 AM
Nice squirrel by the way. :)


12-11-2013, 06:27 AM
Hey Thanks Guys... I'm on 11.5 but haven't tried 11.6 yet.. that was my next plan.. It's funny but i tried running this test on our farm with BNR and it came out ever worse.. it's like every machine placed the fur differently. Maybe it's not the latest LWSN. BUT i am using a dome light, that may be my problem. I didn't know that Fiber Fx wasn't playing nice with that kind of light sub samples and all. I'll try that route with a new light. I'll also check the shadow density as well and let you know if it worked.

Yeah that like guy is coming along pretty well for a test :)


12-11-2013, 08:30 AM
Yup that did it.. had the wrong kind of lights in the scene... the Dome was the problem.. as a still it made it look great but not for the animation.

Thanks for guidence!

12-11-2013, 06:57 PM
BNR seems to have some issues as I've seen it mentioned elsewhere as being a problem.

Yeah, dome is get for getting nice soft shadows, but come with enormous rendering cost. I use a distant light for just the hair objects in my scene, which speeds them up quite a bit.