Hi @Y0Tay – I’ve had the same question, and after a couple of weeks of spending way too much time on this, I believe that I have figured it out (or at least part of it --hopefully someone who knows this workflow better will reply and correct what needs correcting in the following).
Here’s how I managed to put Metahuman facial animation on a Fortnite character:
I copied/pasted all the animation curves that began with “CTRL_expressions_” from the animation spit out by the Metahuman performance asset (in UE5.3) into an animation of the same length that I made for the FN_Mannquin_Skeleton (in UEFN). However:
(1) I think you need to do all the copying/pasting in UEFN (as the UEFN curves clipboard seems to work a little differently than the one in UE5.3). But exporting animations as FBX often seemed to remove all animation curves, so I first exported/imported (as FBX) the Metahuman identity skeletal mesh to get it into UEFN. Then I separately exported/imported the animation spit out by the Metahuman performance asset (selecting the Metahuman identity skeletal mesh on import dialog). This preserved all those precious animation curves.
(2) To get the curves to work right on the FN_Mannequin_Skeleton, I think you need to manually add the following curves to the FN_Mannequin_Skeleton animation: “is_3L” ; “DisableFaceOverride” ; and “default” [and then in the dropdown for “is_3L” and “DisableFaceOverride” select Convert To Metadata. Not sure what “default” does but in the comedy club animation it is given a constant value of 1.074. I set this to metadata as well so it has a constant value of 1.]
(3) In addition to the “CTRL_expressions_” animation curves, the comedy club template animation is using curves like “head_cm1_color_head_wm1_browsRaiseInner_L” and “head_wm1_normal_head_wm1_browsRaiseInner_L”. It looks like first curve has data copied over from CTRL_expressions_browRaiseInL, but this data has then been scaled down (for example, as if the Transform tool in the curve editor had then been used to squish the curve down). The other “…color_head…” curves look like they were created using the same pattern. All “…normal_head…” curves are precise duplicates of the corresponding “…color_head…” curves.
I hope this helps (I was certainly glad to finally figure something out)! I hope that someone who understands the Metahuman Animator → Fortnite Character workflow better can set the record straight.