View Full Version : Is there a shaky IK solution?

07 July 2005, 09:36 PM
Hi all. I was wondering if anyone knows how to work around shaky bones. I have a mechanical arm rigged with an IK handle and it works fine, but when I place it about 6 km from the origin the bones shake whenever I try to animate the IK handle. I guess its because its far away from the origin, so is there a way to get around this?

07 July 2005, 09:44 PM
LWs IK has that "bad habit", i think there are some workarounds to minimize the problem, the one i used the most was: FK :scream:

07 July 2005, 10:29 PM
That or shift the scene so that at the moment you are depending on smooth IK, that part is MUCH closer to 0 0 0.

You could analyze some ways to optimize the scene so that it stays within the confines of the mathematical precision available to you. Chuckle... That is to say, do you need everything that's in that shot to be in that scene to get the shot you want? Gosh, that was even more convoluted, but I hope you get the gist. ;)

07 July 2005, 10:42 PM
Thanks for the suggestions.

I get what you were saying, uncommongrafx. The scene I'm working on is quite crowded, and the particular shot I'm talking about only has a few things in view. In the interest of time, however, I'll use Sil3's suggestion. The arm only has 3 animatable joints anyway.

07 July 2005, 01:12 AM
why not parent everything to a null and move the complete scene, so the action is a 0,0,0 ?
( for speed uses Schematic view or TM-P Quick parent plugin )

I do this alot as i work though scenes the action may move away from center, as the scene keeps moving away from center, i keep everything at center by moving everything with the null.

Hey works for my scenes :thumbsup:

07 July 2005, 02:17 AM
Some time ago, I devised a method to avoid parkinson in LW :) This technique was improved by Emiliano Stefanach to apply it to a bones rig similar to ACS of Lukasz Pazera. Perhaps can help you too:


07 July 2005, 04:36 AM
Without question, Sil3's advice gets the job done and the deadline met. But as Thomas states as well, a Master Null in such a scene takes care of a lot of this issue and offers the ability to have the full scene at hand.
Rendering wise, cutting away that not in the shot is the most economical and efficient if you plan it into the process. Modular Big scenes of this sort are most efficient. LW layers can play a big hand in this. ;)

07 July 2005, 01:03 PM
You can still use IK for the animation, ignore the shaking. Then, in the end, select all the bones of the arm and make a keyframe for them in the same keyframes of the IK-Goal. Then, disable IK for the arm.

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