I was doing the last work on my assignment last night and although I've had this happen before, I felt the need to try to understand it so maybe I can stop it from happening. It may be a glitch though.

OK in my sequence, I had to have Tin Servant follow Tin Woodman's crown that rolls out from the doorway that Tin Woodman just fell through. As the crown rolls across the floor, it loops around Scarecrow who's in the middle of the hallway. When I did this, it was basically a re-work so my poses were already established so all I did was adjust the keys needed to turn him slightly (hips, chest and head, eyebone, etc) to show that he's following the crown with his eyes as it rolls.

Well, Tin servant is holding an instrument in both hands (a concertina accordion type of instrument). when I scrubbed the animation, Tin Servant's hands (and instrument which is constrained to each hand bone) moved with the hips and chest bone. I wanted to keep the movement separated so I switched the arms to IK.

When I switched to IK, I switched back to FK to make sure I created keys in both modes. When I did this the hand position jumped a little. So I tested it, I kept switching back and forth from IK to FK and vice-versa and the arm bones kept creeping to a position slightly offset from the last.

What the heck causes this?
Is it controllable?
Is it a glitch?

Thanks,
George

I brought this up a while back. The response was "Don't keep switching back and forth!"

In practice the intial shift should be small enough that it doesn't get noticed. (Just don't keep switching back and forth.)

OK but no one knows why it does this?

So the answer is it's a glitch.

The characters in TWO were rigged before the IK/FK switch was completely worked out, so their switch will twitch under some conditions. I couldn't go back in and change it because too much animation had already been done using the old setup. If you try the same thing on the current Squetch Rig, it shouldn't have a problem.

That's good to know. Thanks David

George