IK Leg issues

Raz · May 2010

New to rigging here. I've done rigging on basic meshes when the legs were straighter, but now I'm working on a fairly realistic female model. Her legs are a bit bowed, so the leg joints don't go straight up and down if I align them with the leg (knee is in a little bit, and obviously for a female, the hips protrude a bit). If I follow the angle of the leg with the joints, the IK handle generated will bend the leg in the wrong direction because of the knee. I'm about to just move the hip joint in a bit and the knee out to get the leg in a straight line so the IK will work. It looks strange to me seeing the joints not centrally located within the mesh they will be affecting. Is this the right solution, or is there a better way?

Thanks in advance.

ivars · May 2010

If you're using Maya, you should use "Set preferred angle". Rotate your joint to form the correct rotate plane, and use set preferred angle on each joint, when creating the IK it will use that rotate plane.

kodde · May 2010

Try using a pole vector control object as well to control where the knee points.

1. Create any desired object that will be your pole vector control object.
2. Place it in front of your knee, not too close.
3. Select your IK handle, then shift-select your new control object. Make sure you select them in the right order. Go to the Constains menu (located under Animation module) and add a "Pole Vector" constrain.

Your new control object should be controlling where your knee points.

Oh, and welcome to Polycount.
Stay a while.... staaaaaaay forever!

Shawner · May 2010

Another key think to consider when creating your joint chains is keeping them planar from root to tip. I've found IK behavior much more predictable when I follow that rule. There is some sacrifice, but since hinge joints don't usually twist the joint location doesn't have to be directly on top of the target, it can be to the side.

Cheers,
Shawn

IK Leg issues

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