Rig flips upon ik\fk switch (Maya)


Hello everyone!

I’m having a problem with my rig. While left leg works as expected, the right one starts making some strange stuff as soon as ik\fk switch is set to 0.5. I’ve attached the example scene to make it easier to understand my horrible explanations =).
I use native switch for ik solver and orient constraint with weights controlled by expression for the toe. The toe’s FK goal is parented to the shin, the IK goal is parented to the foot controller. While this works well for the left leg, the right toe flips. If I unparent the toe’s fkGoal, it suddenly starts working as expected. If I parent fkGoal to the pelvis - flips. If I Parent Constraint fkGoal to the shin - it works, but only while the fkGoal is parented to any object that is lower in hierarchy than Pelvis. Basically, if fkGoal is parented (not parent constrained, just parented) to the Pelvis or anything higher in hierarchy - the toe flips. I’d be happy enough with parent constrained fkGoal, but I want to keep it’s channels clean from any connections. I also tried Parent Constraining an empty group to the shin (while keeping this group actually parented to the world) ant then parenting fkGoal to that group, but the toe again flips.
I’m assuming that it may be somehow related to joint orientations, but I’m not that experienced to be shure about it.

Any help is appreciated.


After googling I’ve found some sort of a workaround (found it here): I have changed the contraint’s interpolation method to Shortest. It still flips when ik and fk goals match in a world space coordinates, but at least there is no big chance of this happening during animation.
But I’m still wandering if there is some solid solution for this kind of a problem?..


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