I've downloaded a windmill model from sketchfab and when I try to import it into unreal I'm getting en error saying it can't import because it has multiple root bones. I don't understand what they mean and how to fix it. Since it seems impossible to move a bone, do I have to re-rig it?

This is how it looks in blender:

screenshot of the windmill

  • 2
    $\begingroup$ You need to switch to Pose mode to move the bones. Also, armature must be in Pose Position not in Rest Position. There are 2 buttons to switch between the modes: i.sstatic.net/7L2yF.png (ignore the tooltip, the image is from another question) -- about the Unreal problem: I guess it's because the 3 bones are all siblings in the bone hierachy. So you have 3 root bones. Have a look at the outliner (top right in the screenshot). You can see the bones are all at the same hierachy level. Edit the armature, add another bone, name it "root" and make the other bones children of it $\endgroup$
    – Blunder
    Commented Mar 10 at 17:19

1 Answer 1


The root is the top level of a hierarchy.

There are two levels to look out when exporting: the objects' and the bones within armature objects.

Object: the armature must be the only too level parent of all the objects meant to be deformed by that armature.
In your case, if the cubes 45 and 51 are part of your rig, you should parent them to your armature object.

Bones: an armature should have one top-level bone in the hierarchy and all the other bone must be children.
In your case, you have three top-level bones. Either parent two of them to the third, or make a new bone to parent these three bones to.

To parent things, select future childrens, then future parent and press Ctrl P.


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