Arm bending wrong way

[VegaOmega]

I'm in the process of rigging a bipedal character at the moment, I just set up the IK handles between the Right shoulder and the wrist.  However, the Right arm doesn't bend in the it is supposed to be, the elbow bends the wrong way when I play around with the IK handle...  I've tried deleting the handle, rotating the joints, then re-applying the handle but that doesn't seem to work.

Please help!

[Anonymous]

post a picture of the joints you have the IK on.

[saihtam]

I can imagine you have the joint chain too straight/beinding the wrong way. This will confuse the IK solver if you do not use a pole vector constraint. Remember that the elbow joint is usually further back in the arm.

[jasonwestmas]

Create some "pre-bend" (Slight Angle) in the knee or elbow before you apply your IK. That will fix the problem immediately. Then apply Pole Vectors as you need them.

[VegaOmega]

Here is a picture of the rig so far.

[Anonymous]

Yes by the looks of it you applied the IK to a straight arm (model). You need to have a slight bend in the direction you want the arm (model) to bend as maya will confuse it since it cannot read the mind of the animator, yet ha.

[VegaOmega]

Ah yeah, I did at first.  But then I applied it when it was bent and it still bent in the same fashion.

[jasonwestmas · Accepted solution]

K, if it is still doin it I would Unparent the hand from the arm and then
redraw the arm joints. Draw them from the front orthographic camera if you
aren't already. Put a little more bend in the forearm/elbow and try the IK
handle again. Also use RP IK solver but I doubt it matters to solve this
particular problem. Usually it's just a pre-bend problem.

Also if you right click on the IK handle you can see a menu that has a
option that says assume preferred angle, set preferred angle, and disable
IK handle. If you disable the IK handle you can then pre-bend the arm
joint. Next Assume the preferred angle. Then turn the IK handle on again.
You might have to delete you pole vector before hand to get something
predictable but honestly it's just easier to start over and redraw the arm.

[VegaOmega]

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@jasonwestmas wrote:

Also if you right click on the IK handle you can see a menu that has a
option that says assume preferred angle, set preferred angle,

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Thank so much! This fixed it!