Animation Retargeting

What is Retargeting?

Animating a character from scratch is slow, tedious, and — let's be honest — a terrible use of your time when thousands of great animations already exist. The problem? Those animations were made for a different skeleton. Different bone names, different axis orientations, different proportions. In professional studios, fixing this is a multi-hour ordeal involving Blender, manual bone mapping, and a lot of staring at quaternion matrices.

Retargeting takes an animation from one skeleton and maps it onto a completely different one. Black Box Animator does this automatically. It detects the source platform, maps bones using standardized IDs, handles coordinate space differences, resolves pose mismatches, and transfers the motion cleanly onto your character.

What used to require Blender expertise and hours of manual bone mapping now takes about 10 seconds.

Supported Animation Sources

Bring your animations from wherever you found them. We handle the translation.

Supported Target Models

Your character can come from pretty much anywhere. The retarget engine uses fuzzy bone matching and platform-specific naming patterns to figure out what goes where.

How to Retarget

Six steps. No PhD required. (Although we have one, and we promise you don't need it for this.)

1. Load your target character This is the model you want to animate. Click Load Model and pick your GLB, VRM, FBX, or GLTF file. Your character appears in the viewport.
2. Click "Import Animation" in the left panel You'll find it in the sidebar under the animation section. It's hard to miss — we made it obvious on purpose.
3. Select a Mixamo FBX, BVH, or GLB file Pick your animation source file. The retarget engine immediately identifies the source platform and starts mapping bones.
4. Review the bone mapping preview A preview shows you which bones mapped successfully. Green means fully mapped. Yellow means partial — some bones didn't have a match but the core skeleton is fine.
5. Click Apply The animation transfers to your character. That's it. The heavy lifting — quaternion conjugation, coordinate space transforms, pose normalization — happens behind the scenes.
6. Hit Play to see it in action Press Space or click the play button in the timeline. Watch your character move. Tweak if needed. Export when ready.

Batch Retargeting

Got a whole folder of Mixamo animations you want on your character? Don't import them one at a time like some kind of caveman.

Use the Bulk Import button. Load multiple animation files at once, and the retarget engine maps them all onto your character in a single pass. Same bone mapping, applied across every clip. Walk, run, jump, idle, dance — all transferred in one go.

How It Works (Under the Hood)

You don't need to know any of this to use retargeting. But if you're the kind of person who likes to understand why things work, here's what's happening when you click that button.

Platform Detection

The BoneMapper module examines the source skeleton and identifies the platform. Mixamo uses names like mixamorig:LeftUpLeg. VRM uses standardized bone IDs. Meshy and TripoAI have their own conventions. The mapper recognizes these patterns and selects the appropriate mapping table.

Bone Mapping

A set of standardized bone IDs — hips, spine, leftUpperArm, rightFoot, etc. — acts as a bridge between naming conventions. Source bone names are mapped to standard IDs, then standard IDs are mapped to target bone names. This two-step approach means adding a new platform is just a new mapping table, not a rewrite.

Rotation Transfer

This is where it gets gnarly. Different rigs orient their bones along different axes. A Mixamo arm might point along X while a VRM arm points along negative-X with a Y-up twist. The engine uses world-space quaternion conjugation (R¹ × δ × R) to transfer rotations while respecting each rig's coordinate conventions.

Pose Normalization

T-pose and A-pose are not the same thing. In a T-pose, the arms are straight out to the sides. In an A-pose, they're angled about 30 degrees down. If your source is T-pose and your target is A-pose (or vice versa), the engine detects this and compensates automatically using direction-gated world-space transforms.

Troubleshooting

Retargeting is complex under the hood, and occasionally things look a little off. Here are the most common issues and how to fix them.

Arms look wrong

Usually a T-pose vs A-pose mismatch. The engine handles this automatically in most cases, but if the arms look twisted or angled incorrectly, try clicking the Force T-Pose button on your target model before importing the animation. This resets the bind pose to a clean T-pose so the retarget math has a consistent starting point.

Fingers don't animate

The source animation needs finger bone data. Most Mixamo animations don't include finger keyframes — the hands just stay in a default pose. This isn't a retargeting failure; the data simply isn't there. Try a different source animation that includes hand detail, or use Forward Kinematics to pose the fingers manually after retargeting.

Animation is too fast or too slow

Frame rate mismatch between the source animation and the target's expected playback rate. BVH files commonly run at 120 FPS while your scene might expect 30 or 60. This will be addressed in a future update with automatic frame rate normalization. For now, you can adjust playback speed in the timeline controls.

Model disappears after import

This can happen with scale mismatches — the animation teleports the model far from the origin. Click anywhere in the viewport to re-center the camera, or press F to frame the model. If the model is still missing, check the console for import errors.

What's Next

You've got an animation on your character. Now what?