unirig — automatic 3D rigging (skeleton → skin → merge)

Keyword: unirig · auto-rigging · skeleton prediction · skinning weights

Only rig assets the user is licensed to modify. UniRig is MIT-licensed, but its checkpoints, the Rig-XL/VRoid/Objaverse data, and the user's own models each carry their own terms.

UniRig is a two-stage autoregressive rigging framework: a GPT-like transformer predicts a topologically valid skeleton from mesh geometry, then a bone-point cross-attention model predicts per-vertex skinning weights. A third step merges the predicted rig back onto the original (full-resolution, textured) asset.

The single most common failure is skipping the merge stage or merging the wrong file — see Step 5. The second most common failure is an environment that silently lacks CUDA extensions.

When to use this skill