flipping Knee
 

Hey all. Sorry for asking for help so soon again, but I'm really trying to get this right. On the first video of the caveman rig, the author makes the knee and his doesn't flip. This is the second time I have redone it though and it's flipping real bad.

It doesn't flip when I move the heel up or down, but when I move it forward or backward it goes haywire. Is there something in the later videos where he fixes that (i.e. adds a constraint or something) or should I go through it again? Thanks

I would really appreciate it if someone could help me. I've tried a lot to get that knee going, including making a null to act as a goal for the lowerleg. While that kind of worked, it wasn't really smooth and led to jerky bone movement.

I gave the two leg bones more of a bend, but it only gave me more leeway before the knee eventually flipped again. There has to be some better way than this.

It really sucks to have such a problem in the FIRST video out of 13.

hey bro thats what the forums r 4, ask as many questions as u want as often as you want, dont feel bad......... I havent done the caveman tut yet, so I dont really know what the problem is, but maybe if you'd explain whats happening in more detail, or show some pics we can try and figure out a solution

By "flip" I assume you mean that the joint is bending backwards?

I haven't done the caveman tute but I assume that it's a joint bending the wrong way while using IK. That wierd flippy-twitchey action sometimes happens when the bones/skelegons are created on a perfectly flat plane.

Couple things you could try. One is to limit the pitch (or whichever) in the motion options for the offending bone. Or you could also try to add some stiffness to the bone.

The best way to fix this though is to pre-bend the joint a bit. Don't have all the points for the bones in a perfect plane. For example, move the joint for the knee toward the kneecap so there is a bend in the joint before you apply the IK.

Hope this helps.