Nodes attached to a KinematicBody randomly get stuck in space

[mysticfall]

Godot version:
master / 6e200b1

OS/device including version:
Manjaro Linux 17.1

Issue description:
I have a 3D character with rigged animations. I made the root of the hierarchy as KinematicBody and attached other items like hair, clothes, and camera to it.

Then within _PhysicalProcess, I move the whole hierarchy with MoveAndSlide and also change position of a single control bone in the same process.

About 8 out of 10 times, it works as expected. But sometimes, random parts like camera or hair, or even multiple bones 'fall apart' from the character when I move it, resulting in something quite interesting as shown in the screenshot below (I wish I could make a video of it - it actually looks way cooler when it moves) :

When it happens for such items like clothes or bones, they get stuck in the space but still move according to the character animation, albeit in a distorted manner.

I know it's a bit vague but have little idea how to track down the problem further. If you could suggest any way to test it on my part, please let me know.

[mysticfall]

It took me more than 30 attempts to reproduce it and capture it to a video but it was totally worth it 😛 :

• https://www.youtube.com/watch?v=OIheviCea20

I feel tempted to somehow find a way to reliably reproduce it and make a game out of it.

[mysticfall]

It may or may not be relevant to my issue, but someone from the Discord channel suggested that #16450 looks similar to this problem.

[AndreaCatania]

The thing is, why fix it? is so cool :D seems an effect made adoc.

Joking apart I think that you are wronging something.... but in order to be sure it's required that you send a sample project

[mysticfall]

Most relevant code that pertains to the issue can be seen from this location:

• https://github.com/mysticfall/AlleyCat/tree/master/Program/AlleyCat/Locomotion

As you can see, it's a relatively simple code and the most unusual thing I'm doing is probably changing bone position by code every physical frame, which I believe to be a permitted operation.

And sometimes even the camera is detaching (or getting stuck in space) from the character hierarchy in the same manner as clothes do, so I doubt if it's something related to the way the character is rigged or how I'm moving one of its bones that could be the main cause.

[AndreaCatania]

Is it possible for you test if this bug still happen with: #28909

[mysticfall]

In fact, I haven't seen this symptom for quite a while. I'm not too sure what exactly, but apparently something must have fixed the issue for me already.

I'll reopen the issue if I ever see it happen again. Thanks!

[AndreaCatania]

Ok let me know thanks