View Full Version : IK arm animation problem...

05 May 2006, 04:01 AM
okay, i think i figured out why animators don't typical us IK on the arms when animating (unless climbing / grabbing, etc).

The first shot of my one of my scenes is the main character pitching a baseball. The posing in IK was simple and easy, however, when i change the curves from stepped (for blocking) to flat, clamped, angled, whatever -- i get some messed up results.

I am spending so much time just fixing the arms. The body turned out decent, but the legs/feet have a little floating --- but like I said, it's the arms that are killing me, primarily the pitching arm. Its like I have to re-Key every frame of that part.

Has anyone else ever encountered this when using IK on the arms? any remedies or tips???

05 May 2006, 08:09 AM
I actually have to use an IK setup in our current characters at work. The best way to combat the problems is to block out your extremes. Then your breakdowns, then add in extra breakdowns. For me, IK = more keys!

05 May 2006, 11:22 AM
The only time you really want to be using IK arms is when the character has to have his hand stick to something. ie. He plants his hand on a table and leans on it. Or,,, The character picks up a large object with both arms. In the latter, you would use IK arms to stick them to the large object, then animate the object around.

The problem with animating IK arms for acting, or any other type of animation is that you cannot isolate movement on individual bones. The IK solver updates the shoulder and the elbow at the same time, making it nearly impossible to isolate rotation and get good overlap in the arm.

As far as a solution, I'd say if you can manage the time, start the arm animation over with FK arms. If not,, then just live and learn.


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05 May 2006, 11:22 AM
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