When using the default Metahuman control rig, the position of the pole vector controller changes every time the flag is switched between IK and FK. Consequently, the transforms of the controls break when switching back to IK, even though the joint positions were adjusted in FK mode. Is this the intended specification? If not, is there a solution? Disconnecting the “Match 2 Bones IK onto FK” node does stop the pole vector from moving, but I am unsure if it is correct to use it this way. There must be a reason why Epicgames included this node. I am currently looking into it, but it is difficult.
Match 2 Bones IK onto FK_Connected
Match 2 Bones IK onto FK_Disconected
I didn’t think disconnecting the “Match 2 Bones IK onto FK” node was the right long-term fix, since it’s responsible for keeping the IK controls aligned with the FK pose during switching. I’d first compare your rig against a fresh MetaHuman Control Rig and verify the pole vector’s parent space and offsets haven’t changed. Also, which Unreal Engine version are you using? If this happens in a clean MetaHuman rig, it could be a version-specific bug rather than expected behavior.
I am using version 5.7. I am using a copied version of the default control rig generated when creating a metahuman. It is disheartening if this is an engine bug. After watching other videos, it seems the solution involves assigning the IK key to the frame before the FK->IK transition in the Sequencer. A similar issue occurs with ankle control; while it can be pulled out if I manipulate the Sequencer keys carefully, the foot gets destroyed by a small mistake, making it difficult to use. Thank you for your answer.
