IK problem
 

I'm creating the skeleton for a character I have made in Maya, but am having trouble getting IK to work on his arms.

I made a skeleton for a model the other day and had no trouble at all. All of the limits and degrees of freedom are the same on this skeleton as on my previous model (and the skeleton itself is almost identical), but for some reason this arm refuses to bend. Every joint in the arm won't rotate when I apply IK to it, it just moves around dead straight.

Any ideas what's wrong? His legs are working fine, so I don't see what's different.

It looks like your arm joints are in a straight line. IK chains need some bit of angle in order to know which way to bend. To fix this, either add a bit of rotation to the elbow joint or set a preferred angle on the elbow joint.

...

I could swear I already tried that, and it didn't fix it, but now it seems to work. Strange.

Maya is playing with my mind.

Thanks.

This could work?
 

Hey JimmyC,
Go into the attributes for the ik handle and make sure the stickyness of the ik handle is set to ON, I had a similar problem recently and found that for some reason maya was putting this attribute to off as default, i turned it on and boom it worked a treat? Hope that works for ya :)

You might consider removing the joint between the shoulder and the elbow. Not much purpose for it there.