UE5 Control Rig FK/IK switch

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I’m trying to set up IK/FK switching using the UE5 control rig creator. I’m able to make the IK chain for the foot (for example) working and if I bypass my CCDIK node I can get the FK chain to work as well. I’m just having trouble making an IK/FK switch (matching would be an amazing) but I can not figure it out.

Has anyone gotten this to work? I’ve thought about trying a “Parent Switch Constraint” but don’t know enough to get it to work.

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Hello,

If you check the metahumans body control rig, there is a fkik switch setup that you can switch using a boolean. However it would be better if it could be float but I haven’t found a way to do that yet.

Here’s my test :smiley:

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image3136×1636 472 KB

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Hi AlexA, did you ever find a full answer to this question??

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I’ve found a really useful video for this setup, even though it’s lacking audio it shows the basic setup of the forward solve relatively clearly and it’s surprisingly simple.

  1. Create an FK setup and an IK setup for whatever limb you need it for

  2. Create a bool control and a branch node to swap between the FK/IK setups

  3. Create parent constraint nodes after each FK/IK setup so the IK/FK controls always match the joints, so switching rig types doesn’t move the bones. This just requires one parent constraint node after the FK setup, parenting the IK control to the hand/foot bone, and 3 after the IK setup, parenting the FK controls to their relative bones.

  4. Use 2 hide controls nodes at the front of each setup to easily hide the controls you aren’t using. One to show the proper controls and one to hide the others. Its nice to build this last as seeing both chains and how they interact is helpful.

I’m still wrapping my head around backwards/forwards solves and haven’t tested this yet, so I’m not sure if you would need both FK and IK setups represented in the backwards solve. Will return after some testing.

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