View Full Version : Double Knee Joint with IK

11 November 2010, 09:48 PM
I am not sure how to set up a double knee joint with IK in Maya. If I set the IK from the hip to the ankle, only one of the knee joints rotates. I have tried simple expressions like let the 2 rotations equal each other and they work when you rotate them manually but not with IK. Have also tried SDK but no luck with IK there either.

11 November 2010, 05:03 AM
Can you post a print screen of your basic set up?
I just did a quick test but couldn't reproduce your problem

11 November 2010, 08:51 PM
Here is a screen capture of the skeleton. For illustration purposes... I attached IK to the Left leg, notice how only one of the knee joints rotates. With the Right leg I selected both knee joints at the same time and rotated them together, this is how I want the IK to behave, so the joints split the rotation equally.

11 November 2010, 11:44 AM
Can't reproduce your error either.
Maybe, when creating the joints, they were to straight. In this case you should rotate the joints once, then set their preferred angle.
You can do this by rightclicking the joint, or by puttig the numbers manually into the attribute editor.

11 November 2010, 08:20 PM
So for you guys the IK does split the rotation between the 2 joints?

11 November 2010, 09:15 PM
Yes it does.
You can clean up your scene (delete everything but the leg joints) and upload it if you want.

Also is there a reason why you created an ikSCsolver instead of an ikRPsolver?

11 November 2010, 02:00 AM
I used an SC solver as opposed to an RP solver due to ignorance, I had to research what the difference was and see that rotation would be useful. Im new to rigging, following an Alex Alvarez series on Skinning using wrap deformers, learning as I go. In a new scene I created a chain similar to my leg with IK and it worked... so Im going to mess with it and either figure out the problem or rebuild the legs. Thanks for the replies.

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11 November 2010, 02:00 AM
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