Shaky animations

[Daumus]

I'm exporting BVH files from Motionbuilder to Bento skeleton and i have a certain issue where at high FPS the animations are shaky for some reason, feet twitch around and shake even though the baked skeleton animations in Motionbuilder are fully stable.

If i lower the FPS and bake everything to 10 FPS for example the feet stop shaking but i get a new problem: the loop has a pause when it resets.

https://imgur.com/zxBJqKC

Edited January 15, 2018 by Daumus

[Daumus]

Here's a close up on feet in SL:

https://imgur.com/a/I9Kkt

[OptimoMaximo]

Feet sliding is a known issue with mocap data, when using bvh for SL. The uploader has to convert the animation into a .anim format file for internal use, and it does a sort of key reduction for performance. The result is what you can see yourself. The fact that reducing the FPS decreases the shaking as side effect is due to the amount of data you're feeding the uploader. If you animation has rotations spread across many frames in a second, the uploader finds more data to "clean up", as opposed to the same animation described using less frames in a second.

The only way to ensure stability is to use the native SL format exported from the software. Maya's got one recently, you can find it on MP

[OptimoMaximo]

28 minutes ago, Daumus said:

but i get a new problem: the loop has a pause when it resets.

When doing a fps conversion, as it happens in Maya too, the animation's keyframes are seen as time markers, not frame numbers. This ensures that your animation playback speed adjusts to the new frame number reference and speed; as result, your animation doesn't have the same frame length as before, and some keyframes may fall between frames in order to respect timing in seconds. Make sure to snap all keyframes to frames and that your export frame range matches the frame range in which the animation actually plays in your timeline set to 10 fps.

[Daumus]

I presumed the animation is probably stretched out and smoothed at 10 fps but i've just checked, when i'm exporting at 10 FPS the frame range is the same when it's imported in SL.

You can see the pause in the first video right after the character touches her hair.

I've tried exporting Anim file from Maya 2016 with builtIn plugin but the file ends up way too big, 38mb. Not sure what you meant with " you can find it on MP "

Edited January 15, 2018 by Daumus

[OptimoMaximo]

10 hours ago, Daumus said:

I presumed the animation is probably stretched out and smoothed at 10 fps but i've just checked, when i'm exporting at 10 FPS the frame range is the same when it's imported in SL

right, indeed the two ranges will match between what you exported and SL since the file is the same; what you need to check is in Motion Builder: the new animation frame length needs to be adjusted accordingly. If you leave thee same frames as you had before the fps shrinkage, you obviously get a section of stillness in your motion.

Plus, when uploading a loop animation, the loop settings can not be set as loop in = frame 1 and loop out = last frame. BVH conversion in the uploader has a loop bug, where the first frame is being repeated on 3 consecutive frames, causing a stop-and-go effect on the animation's loop

10 hours ago, Daumus said:

I've tried exporting Anim file from Maya 2016 with builtIn plugin but the file ends up way too big, 38mb. Not sure what you meant with " you can find it on MP "

The anim exporter that comes with Maya is not SL's same .anim format. I wrote a plug in that is available on MP now, that prepares your rig for animation, compatible with HIK and that exports SL's compatible .anim files.