Prevent simple IK bone from flipping twisting backwards when pushing goal null past zero

[GeorgeZ]

Hi Everyone,

I hope you can help me with this because I'm really interested in how to fix this.

In short, I would like to know how to stop the bones from twisting 180 degrees when their goal null is pushed beyond their base's coordinate.

The attached scene is using an off the shelf "IK with constrains" rig with only two bones. "Bone 1" I only want to be able to rotate on the x axis (y and z angle ranges are set to zero) and on x only in a -20 and +20 degree range, so I've set all these.

But when I push the goal null on the Z axis past the coordinate of the base of bone 1 (so grab the goal null and drag it past -5 on the Z axis) you will see that it is twisting 180 degrees and now facing the other (wrong) way and going on.

So the angle range limit is working but I want to be able to make sure that the bones can not twist and go the wrong direction when pushed beyond the limits, they should only be able to move within their angle ranges and nothing beyond that.

Any help or suggestion is greatly appreciated.

IKproblem.hip