How to get 2 bones with IK to sit flat


My setup is two bones with the last bone with an IK constraint targeted at an empty to control. My goal is to use the control to move up/down in Z-axis with the two bones to collapse to the same horizontal X-axis.

In the screencast below I have Rig Arm A that is quite close but still has issues. Rig Arm B reacts less desirably, the Tertiary bone flattens out towards the bottom and swings the opposite way as it gets close to the starting bone.

Any thoughts?

This would be a stable system as long as your bones are aligned on the X and Y axis and the two bones are the exact same length. Otherwise the closer the ends get, the more drastic the divergence.


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Good eye!

Thanks, Cody!