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Mocap Retargeting

Last Updated: 2026-04-30

Sources: - AdvancedSkeleton - "MetaHuman" — Body vs face export, retargeting pipeline - Rokoko - "UE 5.6 Face Mocap BREAKTHROUGH" — Facial mocap, Live Link Hub - JSFILMZ - "Metahuman Animator to Maya Workflow" — Maya interchange - Epic Games - IK Retargeting Docs

Table of Contents

  1. Body vs. Face Animation Export
  2. Retargeting Pipeline (Maya → Unreal)
  3. Noise Filtering & Jitter Removal
  4. Footfall & Contact Correction
  5. Scale & Skeleton Matching
  6. Tools Comparison

1. Body vs. Face Animation Export

Source: AdvancedSkeleton - "MetaHuman" video

⚠️ THE Critical Distinction

Animation Type Export From Process in Unreal
Body Animation Select ROOT JOINT Import FBX → Retarget to MetaHuman SKM
Face Animation Select CONTROLLERS Sequencer → Face Control Rig → Import Control Rig FBX

Body Export Steps

  1. Select the root joint of the skeleton
  2. Export Selection → FBX (check "Include Animation")
  3. Import FBX into Unreal
  4. Use IK Retargeter to map to MetaHuman skeleton
  5. Apply to SKM body mesh

Face Export Steps

  1. Select the face controller objects (NOT joints!)
  2. Export Selection → FBX
  3. In Unreal Sequencer, select Face Control Rig
  4. Right-click → Import Control Rig FBX
  5. Animation maps to facial controls

Why It Matters

  • Body animation drives joint rotations → standard FBX import
  • Face animation drives control rig values → requires Control Rig FBX import
  • Mixing these up = animation doesn't apply correctly or at all

2. Retargeting Pipeline (Maya → Unreal)

Step-by-Step

  1. In Maya: Attach mocap to skeleton (e.g., from Advanced Skeleton)
  2. Select root joint → Export as FBX with animation
  3. In Unreal: Import FBX
  4. Open IK Retargeter → Select source skeleton and target (MetaHuman)
  5. Map chain pairs — Match corresponding joint chains
  6. Retarget animation → Generate new animation sequence
  7. Create Level Sequence → Add retargeted animation to MetaHuman

Chain Mapping Priorities

Priority Chain Reason
1 Spine Core of all motion
2 Legs/Feet Ground contact
3 Arms/Hands Secondary motion
4 Head Tertiary, often simpler
5 Fingers Detail, often skipped

3. Noise Filtering & Jitter Removal

Tool Comparison

Tool Filter Type Best For
MotionBuilder Butterworth, key reduction Professional pipeline
Blender F-Curve smooth, clean Free alternative
Cascadeur Auto-smooth, Gaussian Quick cleanup
Maya Graph Editor filters Per-curve precision
  1. First pass: Butterworth filter (MotionBuilder) or Gaussian (Cascadeur)
  2. Second pass: Key reduction — remove 60-80% of keys
  3. Third pass: Manual curve adjustment for timing
  4. Always verify with reference video

When NOT to Filter

  • Micro-expressions in facial mocap
  • Subtle weight shifts in performance
  • Quick actions (impacts, snaps) — filtering kills their sharpness

4. Footfall & Contact Correction

Common Problems

Problem Cause Fix
Sliding feet Mocap scale mismatch IK foot lock during contact
Penetrating feet Ground plane offset Adjust skeleton Y offset
Floating feet Capture volume error Add foot contact markers
Uneven steps Noise in ankle joints Filter ankle rotation curves

Foot Contact Correction Workflow

  1. Identify contact frames — Heel strike, ball contact, toe off
  2. Lock IK foot to world position during contact
  3. Blend back to FK during swing phase
  4. Smooth the transition to avoid pops

5. Scale & Skeleton Matching

Scale Considerations

  • Match mocap skeleton proportions to target rig
  • Verify bone orientation (Y-up vs Z-up, left-hand vs right-hand rule)
  • Consistent naming conventions — Essential for automation

Common Scale Issues

Issue Solution
Character too tall/short Scale root joint uniformly
Arms too long Adjust IK chain length
Different bone orientations Pre-rotate bones before retarget
Missing bones Add dummy bones or skip chain

6. Tools Comparison

Tool Strengths Weaknesses Cost
MotionBuilder Industry standard, best retargeting Expensive, steep learning Paid
Cascadeur Physics-based, auto-posing, free tier Limited retargeting Free/Paid
Blender Free, full-featured Retargeting plugins needed Free
Maya Advanced Skeleton integration No built-in mocap tools Paid
Unreal IK Retargeter Direct MetaHuman support Unreal only Free