Custom NPC animation system (IK + Retargeter + Blueprint) completely broken after latest UEFN update. Previously working setup now only displays skeletal mesh without animations.
Please select what you are reporting on:
Creative
What Type of Bug are you experiencing?
Devices
Steps to Reproduce
Create a custom animation setup using two IK Rigs
Connect both IK Rigs through a Retargeter (RTG)
Use this setup inside an Animation Blueprint
Assign the Animation Blueprint to a Blueprint (BP) with a Skeletal Mesh
Assign this Blueprint to a custom NPC
Launch the session
Note: This setup was fully working before the latest update without any issues.
Expected Result
The NPC should correctly use the Blueprint and animation system:
Animations should play normally
IK system should function correctly
Retargeted animations should be applied
The NPC should behave exactly as before the update
Observed Result
The NPC only displays the skeletal mesh
No animations are playing
IK and Retargeter systems appear to be ignored
The Blueprint is correctly assigned but animation logic does not execute
Additionally, the following error occurs:
“Ensure condition failed: MeshDescriptionBulkData != nullptr”
(File: SkeletalMeshSourceModel.cpp)
In my project, I used an IK retargeter to modify the appearance of wolves, raptors, and FN mannequins.
My setup is the same as yours.
Before the update, all NPCs were functioning normally, but after the update, NPCs retargeted from wolves and raptors did not play their animations, while only NPCs retargeted from FN mannequins behaved the same as before the update.
In my case, humanoid and non-humanoid skeletons behaved differently, so I added this comment as a supplement.
I apologize if the grammar or phrasing is awkward, as I am commenting based on a translation from Japanese.
No problem, welcome from France! I understand your issue. My NPCs with mannequins are working fine, but the boar, raptor, and wolf aren’t spawning anymore. I think the Star Wars update is the cause, since it introduced a new wildlife spawner with Star Wars creatures, and it might have broken the classic custom wildlife NPC spawner.
I think this is actually updating NEW retargets for NPCS as well. I can’t seem to get a human npc retarget to align properly. Might just be my model though. Will do some more digging.
have you had any luck? as of the recent update, all my humanoid NPCs no longer work with the retarget system. It either does not line up their rigs correctly or the blueprint character does not move, you can see the weapons moving on an invisible skeleton, but the blueprint actor is stuck in T-Pose. Is this the same issue you are having?
