Modify Avatar Mask

Use Modify Avatar Mask to add a custom transform path to an existing Unity AvatarMask. Use it when a layer must include a weapon bone, IK target, attachment, or other transform outside the standard humanoid mask. Open , then select Animation > Modify Avatar Mask.

Fields

Field	Purpose
Root	Optional hierarchy root. The stored path starts below this transform.
Bone To Add	Transform that the mask should include.
Upper Body Mask	Existing `AvatarMask` modified by the operation.

Add a transform

Assign the hierarchy root

Assign Root when the mask path should be relative to a specific skeleton or item root.

Select the transform

Drag the required transform into Bone To Add.

Select the mask

Drag the target AvatarMask into Upper Body Mask.

Modify the mask

Click Add Bone, then inspect the mask’s transform list.

The tool modifies the selected AvatarMask in place. It adds only the selected transform, not its children. Commit or duplicate a shared mask first.

If a path ending with the same bone name already exists, the tool leaves the mask unchanged.