Fix: Unreal Modular Character Mesh Merge Broken Bones

Helmet attached as a child SkeletalMesh stretches weirdly during animation. The child mesh is animating independently instead of following the master pose.

Same Skeleton Required

Every part of a modular character — head, torso, gloves — must reference the same Skeleton asset (not just compatible). Different skeletons mean independent pose evaluation.

Master Pose Component

HelmetMesh->SetMasterPoseComponent(BodyMesh);

The helmet copies its pose from the body each frame — one animation evaluation, perfectly synced parts. Much cheaper than animating each part.

Leader Pose Component (UE5)

In UE5.1+, SetLeaderPoseComponent is the renamed API. Use it for new code — SetMasterPoseComponent still works but is deprecated.

Skin Cache for Performance

For many parts, enable GPU Skin Cache so the skinning is done once per leader. Improves perf and ensures all parts use the same skinned vertex stream.

Verifying

Animations play with all parts moving in sync; no stretching or floating parts. Profile shows a single skeletal mesh evaluation per character.

“Modular characters need a shared skeleton and a leader/master pose component.”

Adopt LeaderPoseComponent early — the rename in UE5.1 is cosmetic now but will become required eventually.