View Full Version : IK causing feet to slip

09-27-2005, 12:17 PM
I have a problem with my IK set up. I've got a character and I want to be able to move his body up and down and have his legs bend. Seems pretty simple and I've done this setup already with another character and it seemed to work fine. So I've rigged this the same (well as far as I can tell) but where as in my other character the feet didn't move at all in this one the feet slip about. They don't go through the floor so it is working to some extent but they just slip outwards.
I've got my Ik chain ending at the hip and it goes down through the thigh and calf bone and ends on the effector bone which hasn't got any IK but is pointing to the null controller and has match orientation on. Have a look at the layout and see what you think. I can't see why this set up would effect the feet but I've probably done something stupid.
None of the bones below the effector have and IK on them.

09-27-2005, 12:26 PM
Is the goal strenght right? If your figure is large or tiny, the goal strength may need adjusting.

Did you build a little bend into the leg? LW's IK behaves a lot better if a joint knows which way to bend first..

09-27-2005, 02:30 PM
Yeah I tried it with a goal of 50 and then something stupid like 200 and it makes no difference. I also keyramed the knees bent slightly to see if that would help but no good.

I might try and cut and paste the other bones from the working mesh in there see if that helps

Pete B

09-28-2005, 10:38 AM
Do you have constraints on any of the channels and are you sure your bones have the proper rotation channels oriented the right way?

09-28-2005, 03:06 PM
Yeah there's not constraints. although there is stiffness but I done this after it wasn't working to see if it helped.
The roations are correct. I drew the bones in the back view so the pitch rotation is perpendicular to the X axis, if you see what I mean.
I haven't got a clue whats going on. I thought iwas something simple but I still can't see what it could possible be.
The bones are slightly bent as well so the Ik responds right. The thing is it is working but the feet just seem to want to move too even though they're not part of the chain.

Pete B

09-29-2005, 08:06 AM
Well I've pasted in my old set of bones and they work. I really don't get why though, it's exactly the same set up but they just work. One thing I have noticed it that on the bones that weren't working properly when I enabled keep goal orientation on the effector bones I found the feet wouldn't really move where as on the good rig when I done the same thing the feet would move to the same angle as the null.
It's as if the nulls just weren't effecting the bones that much even though they had the same settings as the other rig.
I'm glad because I've got it working but annoyed that I haven't come up with a solution. I think what I'll do is post up the rig and see if you guys can figure it our.

Pete B