BD Mixamo → UEFN Rename

BD Mixamo → UEFN Rename takes a rigged FBX with a Mixamo-style skeleton and rewrites its bone names (and matching mesh vertex groups) to the UEFN SKM_UEFN_Mannequin convention. It's a renaming node - it doesn't re-rig, it doesn't transfer weights - but in the game-pipeline context this pack lives in, renaming is the blocker.

Here's the problem it solves: auto-rigging tools like Make-It-Animatable (MIA) and UniRig produce skeletons on the standard Mixamo template - bones named Hips, LeftShoulder, LeftHand and so on. UEFN (Unreal Editor for Fortnite) expects its own canonical skeleton, the SKM_UEFN_Mannequin, with its own naming (pelvis, clavicle_l, hand_l...). Import a Mixamo-named FBX into UEFN and the retargeting has nothing to bind to - the engine can't match your bones to the mannequin's. This node is the bridge between the autorig output and what UEFN actually accepts.

The source confirms it's a Blender-based node: it shells out to a bundled Blender script that renames bones in the FBX and their matching vertex groups, with pass-through for any bone not in the mapping table. The pack's own note: Make-It-Animatable's standard 52-bone set is covered.

How it works

• input_fbx (required) - path to the rigged FBX. This is expected to be the output of BD AutoRig MIA or BD AutoRig UniRig; the node assumes a Mixamo-style skeleton.
• output_name (optional) - output filename without extension. Empty (default) appends _uefn to the input's name, so character.fbx → character_uefn.fbx. You get the output path back from the output_fbx output.

The README's recommended flow is explicit about what comes next: "Use BD PoseFixer Retarget after this to align the rest pose." Renaming gets you the right skeleton names; the rest pose alignment is a separate step, because a renamed rig whose T-pose doesn't match UEFN's convention will still import bent. Don't skip the second half.

Where it fits in the pipeline

The pack's autorig family works in stages: BD AutoRig MIA (or UniRig) rigs the character on the Mixamo template → this node renames to UEFN → BD PoseFixer Retarget aligns the rest pose → export. Note there's also BD AutoRig UEFN in the pack, which goes further - it converts a Mixamo-rigged FBX to the full UEFN skeleton with real skin weights transferred from the bundled mannequin reference. This node is the lighter, cheaper, rename-only step; BD AutoRig UEFN is the heavier weight-transfer version. Reach for this one when the skeleton structure is already close and you just need the naming and vertex groups to match.

Installing

Standard BrainDead install - ComfyUI Manager search "BrainDead" or clone + pip install -r requirements.txt, restart. The real requirement is Blender: this is one of the pack's Blender-backed nodes. The pack bundles Blender 5.0 in lib/ (per the README) so it can work out of the box, but if the bundled copy isn't found you'll get the mixin's error - "Blender not found. Install GeometryPack or system Blender." A system Blender on PATH (or GeometryPack) satisfies it. All V3 API, so keep ComfyUI current.

The gotcha to plan for

The node renames bones and vertex groups by a mapping table, and pass-through is silent - bones that aren't in the table keep their names. If you run this on a rig that isn't the standard Mixamo 52-bone set, some bones will come out renamed and some won't, and the mismatch will bite you at UEFN import time. Check the skeleton's bone list before you trust the output. That's a 30-second look in Blender that saves an hour of "why is the hand not attaching."