The rig I’m using has a Handle attached to the RightHand with a Motor6D. It’s just one part with a mesh welded (WeldConstraint) to it.
This is what happens when I tried to use IK with it.
I was moving the right arm around, then moving the handle, then moving the left arm around, then I came back to the Right Arm only for this to happen:
It permanently bricks the rig until you delete the extra joints and then the pose gets screwed up in Studio, even when the Animation Editor isn’t active.
Repro: ToolAnims.rbxl (24.2 KB)