UE 5 + Groom/Hair is not working properly

Hey all,
I am creating a character to test UE5, and I realized the the hair shader ignores any indirect light. So it gets super dark. Also the Scatter and Backlight from the shader doesn’t seems to be affecting anything.

I set up my scene to work with Lumen, and any shadow that hits it gets super harsh and weird.

The Skylight with HDRI doesn’t seem to affect it as well… I can boost it up, everything gets brighter, but the hair keeps dark the way it was.

Thank you.

Can you post a screenshot?

I think I’ve seen a youtube video on this exact issue and how to fix it, but I’m not totally sure.

Sure, thanks for the reply.

Left is a image of the character inside UE4, the Sky Light affects it’s color and reflection. Not sure if it is getting indirect light. But in UE 5 it is not getting skylight, nor indirect lights. Shadows gets super dark and hard.

Something I realized in UE5, the eye shader settings also doesn’t do anything, the iris mask and iris distance. Gonna test if skin transmission is working.

Here’s the video I saw. Not sure if this is related.

He goes over a few settings and what happens.

Hi Renoli,

Have you managed to sort this out? Having the same issues rn.

Thanks!

When using lumen in an indoor scene, I found shadows getting hard and pixelated. When I baked the scene with proper lighting by switching of lumen and real time capture, the problems were gone.

Either we need to play around with lumen settings a lot or stick with normal lighting, till the issues are updated in the UE5 final version.

I didn’t figure it out.

I ended up doing the project in UE4.27 with Ray Tracing.

A message to tell this issue still occurs in the last version of UE5 (5.0.2), no indirect light bounce and still harsh shadows on grooms.

Still a problem

Works in 5.2
https://youtu.be/M87ZA7zLtEM

It seems to only work well in Cinematic mode in 5.2
In the video, you can see the hair drastically change at 1:24 when it is switched from Cinematic

There’s a cvar called r.HairStrands.SkyLighting.IntegrationType
On CInematic Scalability (Shading), it’s set to 1. On all others, it’s set to 2.

As one might expect for a Cinematic exclusive, it’s costly. But it’s the only way I can find to get Lumen + Skylight + Strands to play nice.

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UE 5.5 has a new cvar that greatly improves skylight occlusion:

r.HairStrands.SkyLighting.ScreenTraceOcclusion 1 combined with
r.HairStrands.SkyLighting.IntegrationType 1