Will the script work with any character?

Uefy script will work with characters with a similar bone hierarchy structure as the Epic Skeleton. You may need to rename the bones and use bone rotation tools provided by the script to meet requirements.

A video showing the whole process is available on the youtube channel.

Will the script work with all Mixamo rigged characters

The script has only been tested and known to work for sure with the default human made character in FuseCC rigged with the Mixamo service.

Any other character types will depend on the bone hierarchy they end up with. If they have the same bones as the default rigged characters then the script will work.

You will need to ensure the character is symmetrical with same pose and size for limbs on both sides.

Mixamo Rigging Options need to be:
Skeleton LOD: Standard Skeleton (65)
Facial Blendshapes: Disabled

Can I use a mesh with ShapeKeys or MorphTargets?

The process of rigging a mesh with Uefy Script requires applying the armature modifier to the mesh. Blender does not allow this if the mesh has shapekeys. You will need to delete the shapekeys to rig the mesh.

You can create new shapekeys after rigging is complete or you can try to copy/transfer shapekeys to the rigged mesh from a different object. However this is a complicated process that might require custom scripting. Refer to StackExchange and Unreal Forum for examples of how people have done this.

Can I choose the original UE4 Mannequin Skeleton when Importing the rigged character?

Yes you can.

Beware that the original UE4 Mannequin requires bone rolls that are incompatible with the way Blender 2.8 works. You will need to maintain two separate blend files. One to create animations and another to export with bone rolls that support import into the engine with the original UE4 mannequin skeleton.

A detailed video on this process is available on the youtube channel.

My character has no bones or the script does not work. Now what?

You can pose the character manually and pose the metarig using the UE4 Mannequin as a target. This will fix the metarig and add twist/other bones.

After that generate the rig and parent the character to the rig as usual. “Build Unreal Skeleton” does not rely on anything from the target character. So the rig will still work and you can still animate and export to Unreal Engine.

Only limitation is the posing functionality for the character is not available.

Can I add extra bones to the Metarig? Do Rigify samples work?

You can add additional bones to the metarig after posing. The generated rig will correctly create the controls and widgets.

However at this time Uefy Script does not automatically add extra bones to the primary Epic Skeleton. An exception to this is the facial rig and extra twist bones which must be selected while posing the metarig.

All other extra bones must be manually duplicated and added to the Epic Skeleton deform chain. This is time intensive process but it does work. A video tutorial on how to do this is planned.

Future updates to the script may be able to automate this process or atleast make it simpler, it is on the wishlist.


Uefy 1.2 now support some ability to add new bones in a semi-automatic way. Currently you can add the following samples:


You can follow this tutorial to see examples of how to register new bones: https://youtu.be/2xVF9QFu-Bw

Please note due to the way rigify organizes bones it is not possible to add child bones to new samples using the bone register opertator. In those cases you may still be able to add child bones by manually editing the rig. Example: https://youtu.be/yu0hXxn1lu0

Note: Re-generating the Metarig with custom bones added to the Skeleton will delete them!

The current workflow is to manually add custom bones to the bone hierarchy created by the script. Since the script is not aware of these extra bone, regenerating the rig from that point on will delete the custom bones and you’ll have to readd them.

I have a few ideas on how to automate this process so the deleted bones are readded. I hope to add that feature in a future update. But for now the workflow is to finalize the base skeleton bones so you don’t need to regen the rig anymore and only then start adding custom bones to the rig.

What are prerequisites for Pre-process (Setup bone names)

The target character’s bone hierarchy must be the same as the Epic Skeleton or the bone hierarchy must be compatible and custom mapping and custom roll data be filled out in the script.

Default custom mapping and custom roll data is filled out for FuseCC default human characters rigged with mixamo.

What are prerequisites for auto posing the Metarig?

Posing the metarig requires a successful preprocess by renaming bones in the target character. See FAQ on preprocess for details.

Additionally the script is designed to work only with the default metarig as it appears when using the Add -> “Human (Meta-rig)” operator. The script relies on bone names to keep track of operations so you can not change any of the names. However you can freely add additional bones and rename them as long as the bone was not part of the original metarig or added by the script itself e.g. the twist bones etc.

A recommended workflow would be to add a new default meta-rig. Use the script to pose it and only then add additional bones if needed without touching any of the existing ones.