MMD World Glitch – “Ice skating”

[DragonAsh]

A few months back, it seems a VRC update broke many, if not all MMD worlds completely. This happens occasionally and it take a while for the creators to update their worlds to fix it.

During one of these updates, something else seemed to break. A few months back, a couple of friends and I noticed that some, but not all models would “ice skate” in the middle of the platform when their dance station was elsewhere. Their model would go through all the motions but stay in the center. If they had to walk left or right, you would see them do it, but they were anchored to that one spot.

The odd thing about this glitch is that it is visible to everyone else in the world except for the user. So it’s almost like some type of sync issue.

And so, troubleshooting began….

I do not know how to create an MMD world, but on the user-end, I could at least see if it was related to my VRC client, model or something else.
My VRC client is vanilla. No mods, except for OVR Advanced Settings, which I have manually turned off for the testing.

Is it avatar specific?

• No. After numerous tests with many avatars, it seems to happen with all of them.
  
• How the avatar is made in blender does not seem to be the issue
  
• Additionally, said avatar could be perfectly working one minute, then break.

Is it Avatar version specific (2.0 vs 3.0)?

• From our tests, no.

Is it the world? (Is it just broken/Instance open too long?)

• We stuck to more recent/updated worlds such as Maki’s and Aeriiie’s as they would be more in line with the SDK’s and Unity versions.
  
• Are MMD worlds just buggy to begin with? No idea. The way they are made could be “hacky”, but I can only speculate.
  
• New instances do not fix the issue.

Is it the song (vmd)?

• Not really. Songs that worked fine, suddenly stopped working. It seemed very random.

Is it the VRC client?

• Doesn’t seem to be.
  
• We have deleted all cache and have done complete uninstall/reinstalls while also deleting all folders associated with VRC before the reinstall.

Is it VR?

• Yes!?
  
• During the tests, we noticed that desktop mode users never had the problem. Once I started having the issue, I swapped into Desktop mode and used the same model, and the problem did not happen! In addition, when I went back into VR, the model would work for a short time, then break again. This “fix” was not consistent though as the swap would not always get rid of the glitch when back in VR
  
• It is confirmed that while in desktop, the issue does not happen.

So that’s it in a nutshell. Something in VR or the way someone in VR interacts with the world kind of breaks. I have no idea what, but it ruins the experience for said world. Should anyone have any insight on this, that would be wonderful.

If anyone is curious, these are the two world we commonly use:

Maki’s MMD Dance World (it set the standard a while back!)
https://vrch.at/wrld_776a6a37-f307-43f4-aeef-8f151f38dba4
Aeriiie’s MMD Dance World (A terrific successor to Maki’s Dance World)
https://vrch.at/wrld_776a6a37-f307-43f4-aeef-8f151f38dba4

[DragonAsh]

Well, not that it matters all that much, but I did find a pseudo "fix".
I have an index, so I'm not sure if this will work on other headsets.

If you have a 3.0 avatar, you simply need to remove your headset briefly when the song starts so you go into your "away mode" and then put it back on.

The model does not lose track of its place in the song and it corrects the issue.

[Madman71]

I had the same thing happened on one of my avatars i was working on
after a'lot of bug testing i noted that i would only happen when her hands
were near or on her head.

i checked her head and the was an Vrc Contact Receiver (Script) on it
which was setup to turn on heart particles that would emanate from her head
when touched by me or others.

So on the Vrc Contact Receiver (Script), under filtering,
there was 3 options

1. Allow self
2. Allow Others
3. Local Only

Both Allow self, Allow Others, were turn on, while Local Only was turned off,
so i turn off Allow self only.

this fixed the “Ice skating” problem and it hasn't happened since.

[DragonAsh]

This issue was resolved in a previous update - Tucker notified the group about it