I have.... many, many times.

Tip:
Shorten your steps by retargetting in 3ds Max.
Example:

~ Mixamo to Max (This is an Dishonored Character) but the SAME principle is applied to CC or ANY character.)




MAP THE BONES:



TPOSE  TO  APOSE


UNREAL Ready! :)

@brisck1,

Forgot to mention.... to SAVE your "Bone Structure" animations."
Do this ONE TIME.... then simply "Drag 'N Drop" from here on out! :Wow:

Cool, could you elaborate on your process a little more?

For example, I'm not understanding the "Map the bones" step. What exactly are you doing here?
How did you get the rig into that A-Pose? Did you do it manually?
Also bone names: how did you convert the mixamo naming conventions to UE4's?

Sorry if these questions are a little bit noob-ish, this is my first time delving into an animation pipeline

Hello,
(Happy to Share) ;)

Note: Remember that part you didn't enjoy (retargetting in Unreal),
...this is NOT an EZ button... You MUST do this ONCE... to create the "Template" for ease of use LATER.

This is not the best way, but it works flawlessly for me.

Example:
(No Animation on Character)
~ Import the Unreal character (A POSE)
~ Hide the mesh and "Helpers"
~ Select all of the "Bones"
"With all bones selected.... SET A KEY on them"

Top Menu: Click the "Animation" tab and choose "SAVE ANIMATION."
Save it in you "sceneassets" folder.
Create (if you don't have one)... an "XAF" folder.
Save it in you xaf folder.
Save the file as (UNREAL A POSE).

Reset to a blank scene.
Load a "CC or ANY" character.
Select the BONES and from the top menu.... Animation - LOAD Animaiton
Load your new xaf file.

Map the Bones (Select the Root)... Now select the other Root.

(Select the X,Y,Z Tracks for Position, Rotation, Scale) ON BOTH SIDES)
(Click the arrow) pointing RIGHT to LEFT
Repeat to MATCH all bones




Result:
TPose to APose
POOF!  :cool:

@brisck1,

I'm no programmers, but if you want to quickly rename bones.... drop this in  maxscript and see if it works for you.

This is one.

Really interesting ideas here guys! I'm going to try them out and will report back on how I get on :)

Remember... whether you retarget in max or unreal... you need learn one of the methods.
And... rename the bone manually or script it.

Good Luck

Ok so firstly, I found this useful maxscript for renaming mixamo bones to match the UE4 rig and adding a root bone (which mixamo characters do not seem to have by default) 


*Link to script is in the video description*

So, then I load my saved UE4 manikin animation (A-Pose) and everything seems to auto map nicely without me needing to remap anything, and I see the Mixamo skeleton move to the A-Pose!... However then I unhide the mesh and see this:


Any ideas as to why this is happening? It looks like the bone rotations are messed up or something...

Without a lengthy explanation.... recall me saying "Clone" the mesh and "Save the Skin."
This is "One" of the reasons I do it..

So.... you could.
~ Import the UE char.
~ Clone the mesh.
~ Save the Skin

Retarget the bones and skin the clone... using the saved skin.
There may be some simple and faster way, but this is what I do.