An odd animation glitch: Is it Poser, BVHacker, SL, or Me?

Heyla and well met!

I had made a series of left-handed sword animations some time, last year. When I had uploaded and tested them, in-world, they seemed just fine, and customers seemed to appreciate them. But about a few days ago, one customer contacted me about an issue regarding one of the left handed animations. When he first deomonstrated the sword strike, I couldn't see what was wrong. In fact, he had to swing the weapon several time before I could see what he referred to as a "judder" at the end of the animation, where there seemed to be an odd flash just as the avie returned to its ready posture. After watching the animation, again, I realized that it seemed to be caused by the legs moving together, slightly, before reassuming their proper positions.

When I saw this, I thought that I had simply let a little animation error slip past me in my initial testing, so a few days later, I loaded up Poser to see which frame needed adjusting. To my surprise, the animation played perfectly. "Well," I thought, "maybe it's something that had gotten glitched after I made a few adjustments to the animation in BVHacker?" (When I make animations, I take the bvh files into BVHacker as a way to preview how the animation should look when I upload it into SL, as well as a way to add in the T-Pose at the beginning of the animation set, as I seem to have a few issues starting the animation with the T-Pose in Poser. It seemed to be a good strategy, allowing me to see if anything went wrong with the exported file, or if there was anything I missed in Poser that only really showed up in BVHacker, for whatever reason.) However, when I loaded up the animation in BVHacker, the one that had been uploaded into SL, I still didn't see any problems. To make sure that it wasn't simply the T-Pose throwing me off, I removed the T-Pose, yet I still didn't see the slight animation glitch that I could clearly see in-world.

At this point, I wondered if, just maybe, this was an issue related to SL, so I logged into SL and played the animations through. At first, the animations STILL played just fine, then, after the fourth or fifth run-through, I finally got the animation glitch that I was looking for. After playing the animations several times through, I discovered that this so-called judder tended to happen inconsistently: Sometimes you'll see it, other times, it plays perfectly. And I'm not sure why. I have a few ideas, and I'm hoping someone can either confirm or correct me, as well as let me know if there's a way to fix this error.

My first theory was that this is a known phenomenon in SL, and that animators simply accept it. However, I began to wonder, because the animation that's causing problems is a speeded up version of the original animation. You see, the original set of animations tend to be 1 to 1.5 seconds long, but a few customers have asked if there was a way I could speed up the animations, a bit. I had actually tried redoing the animations, but with fewer frames, which was the only way I could think of to speed them up. But the result was something that looked pretty bad in Poser, worse in BVHacker, and not even worth uploading into SL once I saw how it looked in the upload previews. Then I noticed that, in BVHacker, there's a button that says "Frame time (m5)," which I could adjust. When this is adjusted, the animation speed can be increased or decreased. In this way, I was able to make two other versions of my animations, one that plays in .7 seconds, and another that plays in .5 seconds, with both resampled to play at 20 FPS. They're not quite as smooth as the animations played in their original speed, but they still looked fairly good, with none of the issues that I would later see, in-world. So I'm wondering if the glitch is related to the idea that there just aren't as many frames between the key frames to smooth out the animations, and every now and then, SL gets a little "confused" about where the limbs should go between frames? If this is the case, is there some type of workaround, or is this something I just have to accept? If the method of speeding up my animations is causing this glitch, is there a different method that won't cause such a problem, or a workaround method that won't cause this problem?

Thank you to any who are able to shed light on this situation. Your help is greatly appreciated!

Keeper S. Karu (KeeperS Karu)

The issue you describe sounds like it may be related to this: http://jira.secondlife.com/browse/VWR-3783

I hope that may clue you in.

Hm... it seems to be similar, but that particualr glitch is more related to animations set to loop, in-world, and my animations aren't looping animations, per se. I have the animations set so that the avatar will begin the animation in a netural, ready posture. The avatar will then swing the weapon, and at the end of the swing, the avatar returns to the neutral, ready posture. But, that detail aside... it does seem like the issues are related to the way that animations are played in Second Life. Hm... Unfortunately, while I was able to pick up a few tricks to help improve the overall quality of my animations, the actual workaround may still not help, as it's a workaround for people who are trying to set their animations up as looping animations within SL. Oh, well, at least I feel I may have some of the answers I'm looking for.

Thank you for the link!

Keeper S. Karu