As I understand it, IK Rig is also used to perform Retargetting between rigs. You setup one IK Rig for each character, then use a IK Retargeter to match the poses between them, and then you can transfer animations.
With UE5.4, they’re planning to introduce Modular Rigging. It’s great and I can’t wait to play with it, but honestly, there’s a massive opportunity being missed here.
Instead, they could use the setup done with the IK Rig (labeling limbs, IK Goals, etc.) to generate a Control Rig from it. Clavicle, arms, head, tails, legs, spine, all of it could be generated in the same way, just by using the labels created in the IK Rig creation process.
We could even leverage this logic to create the “Modularity” features we want! Say, you want Arms to be created with IK as the default, or you want the whole body to use FBIK instead, or perhaps add up-vectors for the FK tail controls.
Let me create a Control Rig from a given IK Rig.
If we have the ability to turn this into a Feature Request ticket, that would get my vote.