- Add NeckBoneChain config (FElevenLabsNeckBoneEntry USTRUCT) to distribute
head rotation across multiple bones (e.g. neck_01=0.25, neck_02=0.35,
head=0.40) for more natural neck arc movement.
- Swing-twist now uses bone's actual tilt axis (BoneRot.RotateVector) instead
of hardcoded FVector::RightVector — accounts for MetaHuman ~11.5° reference
pose rotation on head bone.
- Clean up diagnostic logging: reduced to Log level, removed verbose per-frame
quaternion dumps.
- Backward compatible: empty NeckBoneChain falls back to single HeadBoneName.
KNOWN ISSUE: diagonal tilt is more visible with neck chain — needs investigation.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
j.foucher
8df6967ee5