Hair and fur system - Flickering artifacts

The_Distiller · March 5, 2021, 11:35pm

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):

artofcharly · March 12, 2021, 2:06pm

Hi, you can try to check this =)

Hope this will help with your issues.

Have a great day
Best regards,
Andrew.

The_Distiller · March 12, 2021, 5:39pm

Thanks Andrew!

cgace · November 6, 2024, 4:39pm

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!

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

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

comlys · November 6, 2024, 6:57pm

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

cgace · November 7, 2024, 4:33am

thank you! will try that out!

cgace · November 11, 2024, 7:32am

(post deleted by author)

cgace · November 11, 2024, 7:36am

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?