I’ve been able to import Mixamo animations, first the skeletal mesh and then animations that Unreal autoassign to that skeleton. However, I’ve tried a similar approach with 3DSMax and MotionBuilder and I can’t get it right. 99% of the time it refuses to import the animation because the skeletons do not match (I think they do because it’s the same skeleton file with new animation frames). Some other times it detects the file as another skeletal mesh and it won’t let me choose to simply import it as an animation…
I guess I could import each new animation as a whole new skeletal mesh and then try to manually retarget to the original skeleton inside Unreal… But I don’t know, it looks like a wrong and messy workflow for a fairly simple task. Again, I’m not trying to do some character selector with one animation working on different skeletons or anything “complex”, just trying to import an skeleton and animations made with that skeleton.