MIXAMO via CAT to UE4
I tried setting up a third person character asset in UE4 earlier on and looking for a speedy skinning solution was impressed by the Mixamo skinning (mainly the speed of it but also that it does finger joints without me having to do any real work).
Sending the resulting asset into UE4 needs a step into 3ds Max. This is required in order to supply unique animations.
Mixamo provides an AUTOCat script on their website, which creates a Control Rig based on the FBX rig computed online. Fine, but exporting it to UE4 produces errors -- well, at first I blamed Mixamo for their black magic autorigger but it wasn't their fault at all.
The thing is, in UDK, the export steps involved just exporting the mesh. In UE4 we must export everything, bones and all. So it's just a habit change.
I spent all night trying different possibilities and options before I stumbled onto what makes it work. I can say I'm happy others had this problem too - because I thought I might just be going nuts.
Here's a UE4 Answer Hub thread on the problem: https://answers.unrealengine.com/questions/25797/how-do-i-fix-cat-rig-multiple-roots-found-in-heira.html#answer-62528
