UE5 Imported XGen groom (cache) flickering/getting brighter at specific camera distance

Hello! I’m currently having a problem with a hairstyle for my character becoming much lighter (I assume the shadows are disappearing?) at a certain zoom distance and then popping back to normal. Here’s an example of the issue:


I’ve been toggling every setting I can possibly think of, and I’ve narrowed it down to two potential factors: the flickering disappears if I disable my one spotlight (as opposed to multiple other point lights), or if I change the project settings ‘Shadow Map Method’ from ‘Shadow Maps’ to ‘Virtual Shadow Maps’ (but that messes up a lot of my other nice soft shadows).

The hair is an XGen groom exported as an alembic cache. I’ve done the hack-y method of giving it a negative scale transform when I imported, but changing that to default doesn’t resolve the issue.


If you put a standard grey material on it and its fine then its the material. If its not fine its the LOD, see if you can find out which on it is first then we can trouble shoot the next issue.

The problem is still there when I turn the scene to lighting only, and seems specifically linked to my one spotlight (it’s resolved when I disable that light). I have LODs ‘disabled’/set to 0/set to ‘never cull’ everywhere I can find - hair, character, light - and running r.forcelod 0 in the console doesn’t fix this.


Usually its pointlights that do that. Not spotlights.
Regardless. Thats Unreal for you.
The solution is to not use groom.

Hacky fix here :slight_smile:

Could you do a truck/pan at equal distance, then jump cut and dolly into the next safe distance? Boom, fixed and onto your ArtStation and no one will ever know, whoop whoop!

Then use all that time you saved on “R&D trouble shooting” to learn hair cards :wink:

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Lol! :slight_smile: