I have posted similar questions re: this issue before but no answers received yet have unlocked this problem for me. I am trying to get comfortable with the AutoRig system, and all of the joints and control nulls work fine, but the knee is constantly defeating me. Here you see when I raise the foot up in +Y The knee twists out in an exaggerated bow-legged stance.

When I rotate the Hip affector to fix the imbalance, it works, the knee now moves up and down in IK correctly, but the knee is then distorted in shape as you see in the second pic.

I cannot for the life of me figure out where I go wrong in this. Any help would be appreciated. I have watched several of Michael's tutorials on this but the AutoRig tutorial has no sections on fixing this.

I really wish Houdini would create a tutorial to deal with Issues in the AutoRig. Its a great tool but some more detailed instruction in its use,a s pertains with fixing Rigs that are not quite working yet would be appreciated.

the way the knee moves a highly dependent on the plane of the leg.
can you attach the AutorigSettings for that rig?

Thanks Michael. Scene file link to download below, and the Mesh file is uploaded here.

To Download Scene:

https://www.dropbox.com/sh/b0m20oev88em5pd/AABh15tck5hsXVrcCdmN69-sa?dl=0 [www.dropbox.com]

Hi
the issue is that in your model (which is nice BTW ) the legs are hyperextended


this causes the leg rig to think that the knee is pointing backwards…

I've made a quick hack adjustment to your geometry and made a new autorig - check the attached file

hope this helps

Wow Michael, thank you very much. I can't claim credit for creating the model, it comes from a creative commons site. I appreciate it a lot, this will really help in my understanding of rigging methodology!