Targetless Ik question, Help Please


In my attempts to better understand targetless Ik, i set up a simple test.
I ran into a problem though,that the bones start to reverse direction;
(interpolate in unintended direction from one key frame to the next) at a certain point
and i don’t know what’s causing it.

Here’s the details:

I made a 2 bone armature. Applied Control N and and then Option R, Option G (on a mac)
to clear rotations, translation ( I had read that this was a good idea.)

i applied targetless ik to the second bone in the chain.

I animated a the targetless ik chain by select and G on the second bone of the chain, setting about 5 keyframes to define an a animation that is intended to make the chain rotate a 360 degree arc…

Although i moved the chain always in the same direction, when playing back the animation, it seems that once it reaches about 180 degrees it gets confused and starts to try and reverse direction.

i tried animating it with auto keyframing on as well as setting a key for all the bones for each keyframe (seelct All, and then I key) Neither one seems to help.

the Blend file of this is attached.

Any advice on this would be greatly appreciated,

Thank you,



targetless ik Animation problem.blend (266 KB)