Re-tarjet problem and please advise

Hi, first, I am a total noob about animations stuff.
So I ask for advise. I made some anim bp and retarget to other skelton. All worked fine, well almost…

How do you deal with this kind of stuff?


I don’t think that the anim re-target is being the issue, because the other hand is just fine. so, is the animation and i cant do anything about this?


Ok i didnt have a response but I add more information. Here are the two original - retargeted anims.
Why the lower arm and hand bones are rotated different?? On the robot picture, you can see that the hand is not rotated but the lower arm, instead on the mixamo retarget skeleton, I have a absurd amount of rotation on hand bone.



I have the “Base re target” configuration on both on a T pose. (and other anims work just fine)

On the last picture can be seen

When I rotate this bones on the mixamo character nothing happens, but on the skeleton of the robot yes…

Could be this the problem?
Why are “grey” on the mixamo bone list?
How can i solve this?


EDIT: well, so indeed i think this is the problem. Unreal is telling me “This bone is used for the current mesh but has no vertices weighted against it”
So, the only solution is to modify this on a 3d app?

It’s not a joint rotation or retargeting problem but a skin weighing problem.

To get the forearm to twist properly you need to blend the weighting through a chain starting at the shoulder. To see the needed effect place you right hand out in front of you palm down and rotate it until it’s palm up.

Notice how the forearm twists with the hand? This is what the twist bone is used for.

To fix it in your example you will need to balance the blend between the lower arm joint > lower arm twist > hand.

Thanks FrankieV, ok so the Mixamo export have a problem and/or I must do this in a 3D app.
I don’t know nothing about this, if it’s a lot of work or just two clicks, but well, i think is time to learn.

Looks like your twist bones are not assigned to something. You could do this weight-painting in maya or blender (as you could see lowerarm and lowerarm_twist are different weighted):



…or in blender:

Did you ever solve this issue? I’m pretty much in the same boat I guess.

Hey guys, check out this article on making clothing for Fuse characters - it has a little part about copying skin weights that might be useful for this problem (e.g., try copying the twist weights from the UE4 mannequin to your character).

Would that be done in a 3d application outside of UE4?

@liondog: i asked the same on Mixamo forum, the problem is that some joints are not skinned,


so you must do it your self in a 3d modeler soft like blender, max, modo etc. I am making other thing for my project so I did not have time for that yet.
From mixamo forum:
“We’re aware that the twist joints currently have no skinning. We add the joints in but you’ll need to manually adjust the skin weighting there as our auto-rigger doesn’t currently give them weights.”
And due Mixamo was bought by Adobe, I think this will be this way for a long time.

@n00854180t: hey thanks for this, i will check it !

Correct - Maya, 3DS Max, Blender etc.

Ekran Görüntüsü (53).jpg
please what do you problems help please

This mesh looks like it’s animated by an animation targeted at a different skeleton than the mesh’s actual skeleton.
Re-target your animation to the proper skeleton.
If it still comes out wrong, then your source mesh is probably wrong.