Need help with knees and elbows

Hey, all–

I have my first original creation up and mostly running, but I’m having a tiny bit of riggin problems. I have him rigged like the documentation recommends–esp. the legs–but when I move with the heel IK solver and the leg follows, the knee won’t bend the right way–it flips backwards. Same with the elbows.

I seem to recall a while back that someone on these boards had done a tutorial on how to add knee and elbow IK solvers, but my searches haven’t turned anything up. Can anyone help me out with this? I don’t want him to either goosestep or walk like a chicken!


Which version of Blender are you using?


2.37a for Mac OSX. It should be the most recent–I just reinstalled the other day after my Mac crash, using a freshly-downloaded version.

You have 2 choices

Remake your IK’s with the joints slightly bent in the correct position. Then the joint bends the right way when the Target is in the ‘neutral’ position and you actually have to ‘drag’ the target to straighten the leg or arm. Use a bone for the Target because then it’s already parented to the Armature and you can use it as the Target for a Copy Rotation constraint on the foot.

Or you can add an Empty in front of and slightly above the knee (same principle for elbows though) and parent it to the Armature Object (not to a bone). Then use that empty as the target of a TrackTo constraint on the Bone above the joint.