Epic Games' free iOS app that captures facial motion data from iPhone's TrueDepth camera and streams it in real-time to Unreal Engine via Live Link – enables accessible facial performance capture for MetaHumans, digital characters, and virtual production without expensive dedicated hardware.
What is LiveLink Face?
LiveLink Face is Epic Games' free iOS application that utilizes Apple's TrueDepth camera to capture facial movements in real-time and stream them to Unreal Engine via Live Link. It makes professional facial performance capture accessible to everyone.
Basic Principle
| Aspect | Description |
|---|---|
| Technology | Apple ARKit TrueDepth |
| Blendshapes | 52 ARKit Shapes |
| Transmission | Live Link Protocol |
| Receiver | Unreal Engine |
Hardware Requirements
| Component | Specification |
|---|---|
| iPhone | X or newer (TrueDepth) |
| iPad Pro | With Face ID |
| iOS | 14.0 or higher |
| Network | WiFi, same LAN |
ARKit Blendshapes
| Category | Examples |
|---|---|
| Eyes | eyeBlinkLeft, eyeLookUp |
| Eyebrows | browInnerUp, browDownLeft |
| Mouth | mouthSmileLeft, jawOpen |
| Nose/Cheeks | noseSneerLeft, cheekPuff |
App Features
| Feature | Description |
|---|---|
| Preview | Real-time facial visualization |
| Timecode | Sync option |
| Recording | Local recording |
| Multi-Source | Multiple devices |
Setup Workflow
| Step | Description |
|---|---|
| 1 | Install app |
| 2 | Enable UE Live Link |
| 3 | Establish IP connection |
| 4 | Assign character |
Unreal Engine Setup
| Step | Action |
|---|---|
| Plugin | Enable Live Link |
| Source | Add Apple ARKit |
| Subject | Select device name |
| Animation BP | Process blendshapes |
MetaHuman Integration
| Aspect | Description |
|---|---|
| Direct Drive | Automatic mapping |
| Retargeting | Minimal needed |
| Quality | Very good |
| Setup | Fast |
Animation Blueprint
| Node | Function |
|---|---|
| Live Link Pose | Receive data |
| Blend Poses | Merge |
| Morph Target | Deform mesh |
| Post Process | Post-processing |
Calibration
| Aspect | Description |
|---|---|
| Neutral Pose | Face relaxed |
| Head Pose | Calibrate optionally |
| Offset | Adjust |
| Reset | During session |
Recording Options
| Method | Description |
|---|---|
| In-App | Local recording |
| Take Recorder | Record in UE |
| Sequencer | Directly to Level Sequence |
| External | Sync with timecode |
Timecode Sync
| Aspect | Description |
|---|---|
| NTP | Network time |
| Tentacle | External device |
| Manual | Clap-based |
| Precision | Frame-accurate |
Head Tracking
| Feature | Description |
|---|---|
| Position | XYZ translation |
| Rotation | Head rotation |
| Combination | With blendshapes |
| Application | Character moves |
Optimization
| Measure | Description |
|---|---|
| Lighting | Even, bright |
| Distance | 30-60cm optimal |
| Stability | Fix iPhone |
| Network | 5GHz WiFi |
Multi-Performer
| Setup | Description |
|---|---|
| Multiple iPhones | Parallel possible |
| Subjects | Named by device |
| Assignment | To different characters |
| Sync | Via timecode |
Comparison to Professional Mocap
| Aspect | LiveLink Face | Pro System |
|---|---|---|
| Cost | iPhone available | $$$$ |
| Quality | Very good | Best |
| Markers | None | Often needed |
| Setup | Minutes | Hours |
Limitations
| Aspect | Description |
|---|---|
| Resolution | 52 blendshapes |
| Precision | Good, not perfect |
| Occlusion | Hands interfere |
| Latency | Minimal, but present |
Use Cases
| Application | Description |
|---|---|
| Previz | Fast animation |
| Indie Games | Affordable solution |
| Virtual Production | Real-time characters |
| Training | Learn mocap |
Troubleshooting
| Problem | Solution |
|---|---|
| No connection | Firewall, same LAN |
| Tracking lost | Check lighting, distance |
| Jitter | Smoothing in BP |
| Lag | 5GHz WiFi |
Audio Recording
| Aspect | Description |
|---|---|
| In-App | Record audio simultaneously |
| Sync | To blendshapes |
| Export | With animation |
| Lip Sync | Post-processing |
Export Formats
| Format | Application |
|---|---|
| CSV | Raw Blendshape Data |
| Take | UE Sequencer |
| USD | Pipeline export |
| FBX | Via UE Baking |
Best Practices
| Practice | Reason |
|---|---|
| Good lighting | Tracking quality |
| Stable mounting | Less drift |
| Neutral calibration | Clean starting point |
| Test recordings | Before important takes |
Today
LiveLink Face has democratized facial motion capture. What previously required expensive marker-based systems or dome setups is now possible with an iPhone. For indie developers, previz, and even many professional applications, the app delivers impressive results at a fraction of the previous cost.