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?