jerk at loop point?

I uploaded a few animations that look smooth in Qavimator but have noticeable jerks at the loop point in SL. I've verified that this is *not* caused by the optimization process.

Has anyone else noticed this, and is there a workaround for it, or might I be doing something wrong? Except for the T frame, my animations are full loops, and I use 0% and 100% as the loop parameters.

Thanks for any insight into this. Most of my animations have enough movement that this jerk, if present, wouldn't be noticeable. If the first frame is the beginning of a motion (say, at the top of a pendulum, or the clap of a jumping jack) any jerk isn't very noticeable. But I have some where the first frame happens to be in the middle of a smooth and relatively slow motion, and the jerk is quite noticeable. Also, I believe these anims are all at 10 FPS; some might be at 15.

Here's how it looks: the animation pauses for a very brief moment and then jumps (i'm guessing but perhaps twice as far as it would go in one frame). It's as though one frame is lost, and SL is playing the frame before it twice. Interestingly enough, the jerk isn't visible in the animation preview window. However, maybe it is happening and I just can't quite see it in the silhouette.

If anyone's interested, I'll try to make a trivial example to distribute.

I don't know if this is what's happening to you, but there has long (as in years) been a bug where SL appears to ignore the keyframes at the end of a movement or something and it no longer loops correctly. For example, I had one animation where the person's torso is bent forward and held like that; in SL the animation started with the torso bent forward but it slowly righted itself over the course of the animation, ignoring the keyframe at the end holding it forward.

I have no idea what causes the problem as it crops up more or less randomly (random as in which animations are affected; an affected animation is affected consistently however,) and when I can fix this it's through essentially random changes (eg. change the gender of the figure in Poser, change the interpolation around affected keyframes, etc.)

OK, figured it out -- it's the in% setting. It doesn't seem to skip the ignored T frame properly (or something like that). If I set the percentage up to point it to my first frame, the jerk goes away.

I'll look to see whether this is a client bug, but it might be a server bug.

When doing anything but a full loop, there seems to be a little bit of a jerking problem, no matter where you set your in/out percentages.

I often have the problem too when looping anything except full loop (being, In 0 Out 100).

It's been discussed in a bit more detail elsewhere in this forum, not too terribly long ago. Though to sum it up, it's pretty much a bug that's existed for a while, with no easy workarounds.

I used to see a little jerk between loops when I made frame #2 and the last frame identical. Makes sense, this frame will be played twice, so you'll see a little pause depending on your frame rate. What I do now is this: When the anim is otherwise finished, I make the last but one a keyframe and delete the last one. No double frame anymore = smooth looping.

The optimization algorithm ignores looping and can cause this kind of jerk. The only workaround is to understand the algorithm well enough that you can ensure that neither start nor end keyframe will be optimized out for any significant joint. It's not a trivial assessment.

I do an equivalent thing: duplicate my first frame to the end while working, but by the time I'm done, my first frame doesn't match the last frame; there's a smooth transition.

There is clearly a bug here, but it wouldn't be noticeable unless you use a low FPS rate and your motion at the loop point is very smooth.