MetaHuman Face mesh detached from Body when using SetLeaderPoseComponent in GASP (no runtime retargeting)

Development Character & Animation
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Title: MetaHuman Face mesh detached from Body when using SetLeaderPoseComponent in GASP (no runtime retargeting)

Hi everyone,

I’m integrating a MetaHuman character into a GASP-based project (UE 5.7, Mover 2.0) and running into an issue with the Face mesh positioning. I’m deliberately avoiding the default Visual Override Actor + runtime retargeting approach because of the one-frame lag it introduces.

Setup:

  • Child Blueprint of SandboxCharacter_Mover
  • Invisible UEFN SkeletalMesh runs the GASP ABP (motion matching, Pose Search - the standard driver mesh)
  • MetaHuman components (Body, Face, Beard, Eyebrows, Eyelashes, Hair, Torso, etc.) copied directly into the character BP as children of the UEFN SkeletalMesh
  • LODSync component exists (tried removing it too, did not solve it)
  • Construction Script uses a For Each Loop calling SetLeaderPoseComponent on Body and Torso, targeting the UEFN SkeletalMesh
  • Face is excluded from the leader pose chain (same pattern as the default MH BP)

Hierarchy:

SkeletalMesh (UEFN driver, invisible, runs ABP_SandboxCharacter)
  └── Body → SetLeaderPoseComponent → SkeletalMesh
        ├── Face (no leader pose)
        │     ├── Beard
        │     ├── Eyebrows
        │     ├── Eyelashes
        │     ├── Hair
        │     └── Mustache
        └── Torso → SetLeaderPoseComponent → SkeletalMesh

What doesn’t work:

  • The Face mesh is detached from the body. It appears inside/beside the torso area instead of on the head.

What I’ve tried:

  1. Adding Face to the SetLeaderPoseComponent chain targeting Body → Face snaps to position but inherits UEFN bone scales, resulting in a massively oversized head (Fortnite proportions forced onto the realistic MH mesh).

  2. Assigning ABP_Face_PostProcess to the Face component (the default MH face ABP which has Copy Pose From Mesh with “Use Attached Parent” enabled, plus RigLogic and Head Movement IK) → Face remains detached. I believe this is because Body is in leader pose mode and Copy Pose From Mesh can’t read an evaluated pose from it.

  3. Assigning the Body/Torso post-process ABP as the primary Anim Class on Body (instead of leader pose) so that Body would have an evaluated pose for Face to copy from → character freezes completely, because these are post-process ABPs that expect an input pose, not standalone drivers.

The core conflict:

  • Body needs leader pose (for zero-lag driving from the UEFN mesh)
  • Face needs Copy Pose From Mesh (to avoid the proportion distortion that leader pose causes)
  • But Copy Pose From Mesh apparently can’t read from a leader-posed source

What is the correct way to position the MetaHuman Face mesh when the Body is being driven by SetLeaderPoseComponent from a different skeleton (UEFN)? Is there a way to make Copy Pose From Mesh work with a leader-posed source, or is there a different mechanism I should be using?

I’d rather not fall back to the Visual Override Actor + Retarget Pose From Mesh approach due to the frame lag.

Any guidance from Epic or the community on the production-correct pattern here would be greatly appreciated.

Thanks!