Metahumans eyelashes strange behavior

I got this weird issue where the eyelashes becomes weird outlines when I go in play mode ( its not the case in editor) and also the eyebrows disappeared when in play mode.
moving any hair parameters in play mode will remove the problem but it will also break live link…
the eyelashes on the metahumans sample pack work just fine, it only does that with my own metahumans

Anyone had the same experience?
I am running 4.26 on mac
thank you!

Screen Shot 2021-04-19 at 1.56.44 PM|690x444


same problem.


Go inside Skeletal Mesh of Metahuman and let Shaders Compile.

Remove in construction script !

Hey, in 4.26 I turn translucency refraction off in post process under ray tracing translucency to stop eye lash shadow but in 4.27 I can’t seem to stop the eyelash shadows using this method. Anyone come up with something for this yet?

this causes ray tracing translucency, don’t know how to work around it yet, but it can always turn it off :wink:

A fix for this is to open the face mesh and then in LOD 0 on the asset details on the left hand side go to section 6 and untick cast shadows. This is in 4.27, I don’t have this issue in 4.26 or 5, not sure what’s wrong in 4.27. In the images you can see the ticked and unticked versions.

The issue is that one of the LOD uses cards. and cards cast light differently - particularly with ray trace.
On a proper mesh with tear ducts, occlusion, eyeball, and individualized lashes you don’t get those types of issues:

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Do you know why this is an issue .27 and not .26 or 5?

Could be the hair card material settings (cast shadows as masked) is off, or it could be that the shader in .27 got bad update.
Could also be you have lod disabled in the other engine. Hard to say.

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It’s most likely from this change:

"Re-enabled Transparent objects shadow casting which was disabled in Unreal Engine 4.26. Real time ray traced shadows of transparent objects can only be opaque. Partially translucent ray traced shadows remain limited to baked static lights. Shadow casting for transparent objects can be disabled:

  • Per-material using its Details panel in the Material Editor to disable Cast Ray Traced Shadows.
  • Per-object using the Level Details panel to disable Cast Shadows."

From the release notes here: Unreal Engine 4.27 Release Notes | Unreal Engine Documentation

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