I am currently trying to retarget animations from a Character Creator 4 (CC4) character to a MetaHuman in Unreal Engine 5.6, and I am experiencing an issue where the MetaHuman’s back becomes excessively hunched after retargeting.
When I use the automatically generated retargeting setup without any major modifications, the MetaHuman’s upper body bends forward as shown in the image. However, this issue does not appear in the original source animation.
So far, I have confirmed the following:
- I am using the IK Chain configuration generated automatically by Unreal Engine’s Auto Retarget feature.
- The CC4 character was exported using the Unreal Engine 5 skeleton preset.
Does anyone know what might be causing this issue?
Any suggestions or advice would be greatly appreciated.
How many spine bones does the CC rig have vs the MetaHuman? Could be the autorig not setting up the chain properly. I’d try making IK rigs from scratch. Is kinda tedious, but it gives more control over results. That said, it appears the MetaHuman rest pose has its shoulders pushed further back, so there’s probably going to be some hunching either way.
The spine bones are the same in both the CC4 and MetaHuman characters, ranging from Spine01 to Spine05. However, I have not been able to resolve the issue yet, and I am not sure what is causing it.
Try making your own IK rig for the CC char and a retarget control rig for CC to metahuman (which probably already has an IK rig). Then in the retarget rig, tweak the ref pose for source or target so the shoulders match better. With a smaller delta between the rest poses, the retarget tool shouldn’t try to move the shoulders so far forward when it makes the new anims. I had to do something like this for a mod where I was trying to retarget anims from a chonky masculine monster to a petite goblin girl. Autogenerating retarget rig left me with a hunched back and worse. Tweaking the clavicle and neck rotation of ref pose for OG monster inside the retarget rig produced much better results.
