How to IK the head?



  • Several weeks ago I was complaining that I wished to keep the head straight during animations, and someone advised to "create a temporary IK chain" for the head, and that it would keep the head straight if I moved the other body parts.

    I could never figure out how to create this "temporary IK chain"; I know how to break existing IK chains, which apply for hands and feet, not for the head.

    Anyone knows how to do this "temporary IK chain" thing with the head?



  • Maybe you can try Object > Point At with the head?



  • @NathanK Hello Nathan K; I was actually trying to make the head go through a certain path, like you do to an IK-controlled hand.

    I always thought that was impossible, but someone said it could be done with this temporary IK chain thingie, but I have no idea what that involves.



  • By the way, it's the same problem as IK-ing the end of a tail. If one could IK the last segment of a tail then it would be much easier to move the tail around (rather than having to worry about several tail segments).



  • Page 838 Talks about creating a new IK chain. Basically in the Hierarchy Editor click on the IK chains at the bottom of the figure and when the create IK chain becomes active click it and give it a name. Drag the body parts starting with the hip then abdomen, chest, neck finally head ETA "on to the name of the new IK chain". Now you have an IK chain for the head that you can turn on and off.

    Now the fun part. If you turn the IK chain on and off it will create Key Frames at each point where you made a movement change. Now if you play back the time line without IK on then the head will jump about. To solve this under Animation->Resample Keys -> make key frame every "1" frame. Select the Frame Range of each segment where you had the IK on (and where you need to currently have the IK chain on for this operation) press the OK button and a key frame will be placed at each location and lock the movement in place.



  • @richard60 These are nice tips.

    Yay, the IK creation thing works beautifully! Thanks so much for that, that will be very useful!

    Now, when I started the IK chain from the hip it lost the positions once I turned IK off; it must be a hip thing; it nevertheless worked wonderfully when it started from waist (for Andy2).

    Very smart tip also on preserving every position by making every a key in every frame. I had never thought of that - very smart! What I do for that is this - as I'm always turning IK on/off all the time for precise positioning, if I want to say adjust the hands on frame 50, I key all parameters with (+) on frame 50 and also on the previous (say 40) and next (say 60) keyframes, then I turn IK on, position the hands on frame 50, then turn IK off, then I Resample / Analyze Curvature from frames 40 to 60; that will keep my linear hand movement and positioning at the point I want, and will not key parameters that do not contribute for the hand movement.

    If the linear movents from 40 to 50, and from 50 to 60 take the hand too much out of its path, I just repeat the same on frames 45 and 55 to adjust the path.

    Thanks again for the tip! This works beautifully. Now where's that tentacle... haha...