trying to figure out why the knees are bending the wrong way

I followed the rigging in “the essential blender” and my guy’s knees are bending the wrong way. I need some help here to see what I’m doing wrong.


This is a simple problem, I’m almost sure that when you set the IKs, your tibia was perfectly align with your thigh… In this case the IK had to choose a preffered angle, and I don’t know why, this is 90% of the time a bad one. To avoid the problem, del your Iks, and bend lightly your tibia in the good direction, then set your IK… :wink:

N.tox ->

Thanks for the advice. However, I was unable to make it work. I’m now attaching a blend file containing only the armature (the mesh made it 40-something MB). Perhaps you can help me. I’m using the same armature in a number of my animations and they all have the same problem. Thanks!


backwardsknees1.blend (413 KB)

Oh, and if it helps, I noticed the following printing out to the terminal:

Cycle detected:
leg.control_R depends on master through Parent Relation.
foot_R depends on leg.control_R through Parent Relation.
ankle_R depends on foot_R through Parent Relation
master depends on ankle_R through IK constraint.

I tried to duplicate this and can’t so I don’t know what I did to cause this to print out to the terminal.

a bit more exploration and it seems that there’s something weird going on with the knees. Notice if I put the knees behind the character, his leg bends the right way.


So, basically, with the IK in the upper leg, the To and Lock fields were different for me. I think I may have messed up with Bone roll or something else, but at least it’s working correctly now. Yay!