Hair and fur system - Flickering artifacts

Development Rendering
1

Hey guys. I’ve been messing with the new hair and fur system and found this flickering issue with skinned dense fur. It’s subtle but it makes it not suitable for use in production for me. If anyone has an idea how to fix it, that’d be great!

I’m using these CVars to bump quality:

r.HairStrands.Voxelization.Virtual.VoxelWorldSize = 0.1
r.HairStrands.Voxelization.Virtual.VoxelPageCountPerDim = 16
r.HairStrands.Voxelization.Virtual.ForceMipLevel = 0

Here are two GIF’s that show the issue:

On the nose and between the eyes (my test):

Right above the nose (art by Jelena Jovanovic):

2

Hi, you can try to check this =)

Hope this will help with your issues.

Have a great day
Best regards,
Andrew.

1 Like
3

Thanks Andrew!

1 Like
4

Hi @artofcharly, I’m having an issue with hair in Metahuman and have been following the official guide from Unreal Engine. I also read your comment in the Unreal Dev forum and your blog. I see you’re a groom artist with experience in solving complex grooming issues.

I’m experiencing a strange problem with noise in the Metahuman hair—it still looks like there’s a noise or denoiser effect on the hair. I’ve managed to solve issues with flickering and artifacts, but I’m still struggling with this one. I’ve set all the CVars, read the Unreal documentation, and spent several days googling and rendering iterations, but I still can’t figure out where the noise is coming from.

Do you have any tips on how to solve this or where the noise might be coming from? By the way, I’m using the default Metahuman hair. Thank you!

render setting
render setting723×608 95.3 KB

I’ll link the video here: [Noise on Metahuman Hair](https://www.youtu


Be Magazine : mode, sexo, tendance et beauté - Magazine féminin)

5

It might be the Raymarching. Try these one by one to see if they help any.

r.HairStrands.Voxelization.Raymarching.SteppingScale 1
r.HairStrands.VelocityRasterizationScale 0.5
r.HairStrands.RasterizationScale 0.3
6

thank you! will try that out!

8

Hi @comlys , I tried the console variable you sent me, but the problem still remains. I also tried rendering each light separately and noticed something strange with my backlights. I placed the backlight directly above and behind my character. I’ll attach my lighting setting and setup for you to take a look. Do you have any idea why the backlight might be causing this flickering and noise issue?

LightingSetting
LightingSetting565×181 9 KB

LightingSetup
LightingSetup1338×806 335 KB

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What worked for you in the end?

10

Hello!!

How you fix this issu
I can’t use deep shadow on my project

barre
barre1070×518 66.8 KB

11

What version of the engine are you on? There was a problem a while back with voxels and banding. Does messing with DeepShadowLayerDistribution on the light help at all?

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I am using version 5. Unfortunately deepshadow is not used on this project

13

I see. This might be the issue we had with Voxels a while back that has since been fixed. UE5.0 is pretty old.

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so to be more precise I use 5.4 and it seems that it comes from the skylight

15

the problem was coming from a light that was positioned behind the hair. i don’t know exactly what was wrong with it since i used the same light and the same settings. so i ended up removing that back light, but i still haven’t found the main cause of the issue.

also, i found this free plugin: [Groom Hair Cinematic Tool UE5]. it makes setting up cinematic lighting in ue5 easier by providing a shortcut to access many console variables. might also check out those guys on linkedin.

hope this helps!
@benj_rouzier_2MA @Knoopmas

16

also, check out this official documentation from epic. i forgot the exact console command, but i found one or two here that helped me reduce noise.