I have an animation and skeleton from Mixamo where the character falls to his knees and then slumps over. It was working fine UNTIL I retargeted a UE4 mannequin anim to it. Now the hips dont move at all and the character ends up floating in mid air when lying down. Is there a setting I accidently used? I set the root to none in the retargeting for the other anim and it too doesnt have hip movement. All anims now have no hip movement.
Go to the skeleton settings and set the hip to be animation scaled - or set to skeleton, depending.
That will likely fix things.
I had a similar issue when retargeting an animation. I was able to fix it by properly setting the Retarget root bones in both the IK Rig Source and the IK Rig Target.
I both models I set them to the first bone below the actual root, which in my models were called hips in the source and pelvis in the target.
By right clicking the bone in the IK editor we can clear/set it as retarget root.