RetargetKit — move animation between skeletons

You have a walk cycle on a Mixamo rig and a character built on Rigify. Or a library of mocap takes and an Unreal mannequin. RetargetKit maps the bones for you and bakes the performance across, correctly, on rigs whose rest poses have nothing in common.

What it solves

Retargeting in Blender means either buying a full rigging suite for the one feature you need, or hand-building constraints on twenty bones and hoping. The hard part is not copying rotations — it is that two rigs almost never share a rest pose. Copy the local rotation directly, which is the obvious approach, and every limb comes out twisted.

RetargetKit works in world space instead: whatever a source bone has rotated away from its own rest pose, the target bone rotates away from its own. Measured on two rigs whose arm bones point down different axes, the target reproduces the source's world rotation exactly.

Mapping that mostly does itself

• Ten rig families recognised — Mixamo, Unreal Mannequin, Rigify (controls, deform and metarig), Character Creator / iClone, Auto-Rig Pro, Daz Genesis 3 and 8, VRoid / VRM, and 3ds Max Biped. Each is mapped through one canonical skeleton, so any of them retargets to any other.
• Fingers as well as the body. Every family's hands are in the tables — thirty bones a rig, thumb to thumb, segment to segment. One checkbox turns them on, and they transfer to exactly the same accuracy as the arms.
• Anything else is matched by name. The fallback strips the prefixes, suffixes and separators every scheme sprinkles about, splits CamelCase, and keeps left and right straight — it will not quietly cross the arms.
• The mapping is always shown and always editable. Every pair is a row you can change, disable or delete, with bone-name dropdowns rather than free text so a typo cannot slip through.

Map it once

• Presets. Save a mapping, and its transfer settings, under a name — then load it onto the next take, the next file, the next import of the same character. Presets hold bone names rather than links to objects, so they follow the character across .blend files, and the folder they live in can point at a shared drive so a whole team works from the same mappings.
• Mirror Mapping. Fill the right side of the body from the left, or the left from the right, in one click. Only rows whose mirrored names exist on both rigs are added, so nothing is ever guessed onto the wrong bone.
• Check Mapping. Before a single frame is baked, the mapping is read over for crossed arms, a target bone that two source bones are both driving, names neither rig has, half-filled rows, and limbs both rigs have that nothing is transferring. A mistake in a mapping produces a result that looks plausible until you play it — this is where it gets caught.

Details that matter

• Root motion is scaled by the height difference, so a short character does not inherit a tall one's stride and skate across the floor. Or turn it off entirely and retarget the pose alone.
• Batch mode retargets every action in the file in one go — the point of buying a mocap library.
• Neither rig is modified. The result is a new action; the source keeps its own animation and is left in the state you found it.
• Swap flips source and target, and the mapping with them.

Honest about scope

It transfers rotations plus the hips' position. It does not solve IK, plant feet, or remove the foot sliding that different leg lengths introduce — those are separate problems, and none of the features above changes that. Retarget first, correct the contacts after.

Nothing is locked in

The result is an ordinary baked action. It plays, exports and edits like any other, needs nothing from this add-on once it exists, and works on a render farm.

Tested, not assumed

160 automated checks run in a clean Blender against every release, on rigs that differ in naming, in size, and in the axis their arm and finger bones rest along. The decisive check compares, for every mapped pair and every frame, how far each bone has rotated from its own rest pose in world space, and requires an exact match — fingers included, and across rig families as different as Daz and VRoid. Root-motion scaling, batch mode, side-crossing in both the fallback and the mirror, preset round-tripping, and the source rig being restored afterwards are each verified by measurement.

Requirements

Blender 4.2 LTS or newer. Windows, macOS (Intel and Apple Silicon) and Linux. No dependencies, works offline.

v1.2.2 — Root motion can be keyed onto the rig's root bone instead of the hips, which is what a game engine reads and what an Auto-Rig Pro rig expects: Auto-Map fills the field in for the rig it detects, movement along the ground goes to the root and the vertical bob stays on the hips. Fixed a fault that left the hips unmapped on rigs outside the preset tables, where the character was posed correctly but never travelled. The Auto-Rig Pro deform skeleton is now a rig family of its own.

v1.2.1 — Auto-mapping understands mocap skeletons that name the joint rather than the limb: elbow, wrist, knee, ankle. A Move AI skeleton went from 5 of 18 bones mapped to 18 of 18.

v1.2.0 — Auto-mapping now pairs bones that carry the same name on both rigs before it starts guessing. On a custom skeleton — numbered spine segments, long arm and leg chains, twist bones — the name classifier collapsed every chain to a single class and kept one bone from each: a 62-bone rig produced 10 pairs, and the artist mapped the other 52 by hand. Measured after the change: 62 of 62, and 240 frames retargeted in 1.7 s. Recognition of Mixamo, Rigify and the other known schemes is unchanged.