Performance Issues When Changing Avatars or When Users Join Instances
closed
＃かなたん
I would like to report a recent performance issue related to avatar changes and user joins.
Issue Details:
- When changing my avatar, the client becomes unusually heavy and frequent stuttering occurs.
- This does not only happen when I change my own avatar, but also when other users in the same instance change their avatars.
- Additionally, similar stuttering occurs even when a new user joins the instance.
Additional Information:
- I don’t recall experiencing this issue before the first half of last week (~ 2025-07-27), so it may be related to a recent update or a change on the backend.
- If this is an intentional change, I kindly request that you consider optimizing or improving the current performance impact.
Thank you.
Log In
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_tau_
closed
Since this was traced to VRC Light Volumes, there is not much we can do on our side. Shader loading specifically followed regular Unity flows, and as such can't really be optimized much more. Affected avatars should update to the latest versions of LV-supported shaders.
Please feel free to comment if you believe there is still an actual bug on our end.
CorneliusCorn
_tau_ Is there a GitHub issue or some discussion thread where we can get more information on the performance issues with light volumes?
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_tau_
CorneliusCorn: Here's the links we tracked for reference internally:
Nidonocu
This also appears to affect avatars which use material swaps. I have an avatar that can toggle between two material sets and now when doing so, it can sometimes cause hitches to myself and other players.
lilxyzw
I think the problem is caused by the VRC Light Volumes used in the avatar shader being updated to 2.0.0. I changed the VRC Light Volumes shader code and the problem seems to have been alleviated a little, but the stuttering still seems to occur. It may be possible to improve this by making changes to the shader loading method, but I'm not sure if that's possible.
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_tau_
needs more information
Do you have an avatar ID that causes this issue when loading in?
＃かなたん
_tau_ Thank you. This is probably an issue related to lilToon, but I'll provide the information for different versions just in case.
- Severe issue: lilToon v2.1.0 – avtr_f13914c6-765f-49b3-a160-ae31ad937a5c
- No issue: lilToon v1.10.3 – avtr_ba76c95c-22a5-4e56-abae-db3bc5d4aa59
- Slightly better: lilToon v2.1.7 – avtr_aaa08908-73b6-4958-ad8d-cb7b67c624a3
Incidentally, you may also encounter this issue when joining a public instance with many Japanese users.
If the cause appears to be related to lilToon, feel free to close this issue. Thank you!
CorneliusCorn
_tau_ I have a very old avatar which does this REALLY badly when doing it one emote that activates a screen shader: avtr_d1b0f700-7d62-4acc-985e-e9da1a638d78
Dunno if it's related I figured I'd bring it up
＃かなたん
I would like to add some additional context regarding this issue.
There have been reports that avatars using lilToon shaders (v2) might be involved in similar stuttering during avatar loading. However, it’s unclear if lilToon itself is the root cause.
Personally, I suspect this is not an issue introduced by lilToon recently (since the shader has been available for a long time without such problems), but rather something related to server-side processing or recent changes in VRChat.
For reference, here is a related discussion: GitHub Issue #315 ( https://github.com/lilxyzw/lilToon/issues/315 ).