Unexplained rotation between keyframes

I am animating a human armature (in pose mode). There are two keyframes in my animation between which the armature movement should be fluent. However, this is not the case. Instead, the armature’s rotation goes crazy in between the two keyframes. I can’t find any explanation of this motion in the IPO editor.
Does anybody know the solution to this problem? If you need any additional information, I’d be glad to provide it.

Thank you.

Please provide a demo file illustrating this. Ages ago, I once encountered a similar problem myself (a foot would abruptly flip on to the ground) but that later went away. Some other parts of the rig may be affecting things too.


Fairly frequently, when manually keying, my ipo quat (rotation) curves can get squiggly which results in sudden twists as it goes from -179 to 181 by going all the way around instead of the 2 degrees. I have to look at the curves to tell.

Yep, common to many systems. Add two rotational keyframes in 3DSMax and the damn thing goes backwards.

Here is the actual file. The animation is of a man jumping down a staircase. The problem keyframes are at frame 15 and frame 41. PapaSmurf, I’m probably having the exact same problem. Even so, I don’t know how to fix it. Hopefully there’s a simple solution.



Ankle2-1.blend (433 KB)

It seems to be in your keyframes. I removed them and added a few of my own and the odd rotation went away.

Have you tried re-keying it?

I tried deleting and re-adding the problem keyframes in the Action editor, but I still got the same effect. Is there a way for me to fix this without having to repose the armature for the problem keyframes?