SDK Bug & Feature Requests

VRCSceneTemplateInitializer does not create the default sample scene when the UDON preprocessor symbol is already defined on the first launch. Steps to reproduce Prepare a VRChat Worlds template with the UDON preprocessor symbol already defined. The original report used a project template generated by ALCOM 1.1.5 or earlier. (We added a workaround in 1.1.6.) However, the issue can also be reproduced by modifying a VCC template to include the UDON preprocessor symbol in ProjectSettings.asset . For reference, ALCOM's Worlds template included the UDON preprocessor symbol to reduce the initial Unity launch time by avoiding recompilation of most assemblies. Launch Unity. VRCSceneTemplateInitializer should create the default scene, but it does not. Cause of the bug This bug is triggered by the combination of the following conditions: UdonSharpDataLocator does not exist in the project. This causes Assets/UdonSharp/UtilityScripts to be generated during the first assembly load. The UDON preprocessor symbol is already defined before the first compilation. This causes [InitializeOnLoad] in VRCSceneTemplateInitializer to run during the first assembly load. The sequence of events is as follows: Unity compiles scripts normally. Unity calls the static constructor of VRCSceneTemplateInitializer because of [InitializeOnLoad] . VRCSceneTemplateInitializer checks SessionState.GetBool(HasRunStateKey, false) , which is false , so it sets HasRunStateKey to true and registers an EditorApplication.delayCall to generate VRCDefaultWorldScene . Unity calls some [InitializeOnLoad] methods from UdonSharp, and UdonSharp generates Assets/UdonSharp/UtilityScripts . Unity recompiles Assembly-CSharp and reloads the domain. Note that the registered delayCall is never executed before this reload. Unity calls the static constructor of VRCSceneTemplateInitializer again because of [InitializeOnLoad] . This time, SessionState.GetBool(HasRunStateKey, false) returns true , so nothing happens. As a result, the logic that generates VRCDefaultWorldScene is never executed. (The order of steps 2 and 3 may differ, but the result is the same.) For comparison, the following sequence does not cause the bug when the UDON symbol is not initially defined: Unity compiles scripts normally, but the VRC.SDK3.Editor assembly containing VRCSceneTemplateInitializer is not compiled because of "defineConstraints": ["UDON"] . Unity calls some [InitializeOnLoad] methods from UdonSharp, and UdonSharp generates Assets/UdonSharp/UtilityScripts . EnvConfig.cs checks for VRC.Udon.UdonBehaviour and adds the UDON preprocessor symbol. Unity recompiles all assemblies and reloads the domain. Unity calls the static constructor of VRCSceneTemplateInitializer because of [InitializeOnLoad] . SessionState.GetBool(HasRunStateKey, false) returns false , so it sets HasRunStateKey to true and registers an EditorApplication.delayCall that generates VRCDefaultWorldScene . Unity executes the EditorApplication.delayCall , and VRCDefaultWorldScene is generated correctly. Suggested fix The issue is that HasRunStateKey is set to true before the EditorApplication.delayCall is actually executed. I believe moving the HasRunStateKey assignment into the EditorApplication.delayCall lambda would fix the issue.

In the new SDK 3.7.6, it's now possible to build a world on Linux, but it is not possible to launch a local test with proton. Pls add proton support, similarly to: https://github.com/BefuddledLabs/LinuxVRChatSDKPatch

Currently, the VCC always creates Windows projects by default. When installing Unity, the VCC should install the modules required for Android and iOS. It would be nice if users could choose Android or iOS directly instead of switching to it after project creation.

SDK Version: 3.10.3 When a UdonSharpBehaviour contains an SDK-proxied event method (such as public void OnAudioFilterRead ) that isn't referenced externally elsewhere in the program, the UdonSharp compiler fails to export the symbol under the expected proxied event name. The entry point ends up exported as something like __0_OnAudioFilterRead (the internal/mangled name) instead of _onAudioFilterRead . This causes the entry-point check inside UdonBehaviour to fail, so the event proxy is never registered and the user's method silently never fires. Reference code path on the SDK side: if (_program.EntryPoints.HasExportedSymbol("_onAudioFilterRead")) { RegisterEventProxy<OnAudioFilterReadProxy>(); } Because HasExportedSymbol("_onAudioFilterRead") returns false, RegisterEventProxy<OnAudioFilterReadProxy>() is never called and the proxied event is never delivered. Steps to reproduce: Create a UdonSharpBehaviour with public void OnAudioFilterRead(float[] data, int channels) . Don't reference the method from any other script, UI event, or SendCustomEvent call. Enter Play mode with an audio source that should drive the filter. Observe that OnAudioFilterRead is never invoked. Inspect the compiled program's exported symbols — the entry point is __0_OnAudioFilterRead instead of _onAudioFilterRead . Note: OnAudioFilterRead is also not available in udongraph

[SDK 3.10.3 Unity 2022.3.22f1] Only the first client loads properly. All other clients show up as black screens. This issue started ~1 week ago. Tried: -Reinstalling VRC on steam -Upgrading to the latest SDK version. -Downgrading to an older version. -local testing on a different project.

Whenever I try to update or upload my world to vrc, It says "Cannot start an upload against anything but the latest version of this file-'76,74" Keeps popping up and I cant seem to resolve it. how would I fix this? Unity version is 2022.3.22f1 and the VCC version is (Cant find it but I'm on the latest updated version as of 05/25/2026)

edit scene wait a second SDK spam the log: "Force-enabling Fog" This is output from the EnvConfig.GetFogSettings() method, which retrieves settings. This spam should be eliminated because it overwhelms logs that are necessary for debugging, etc.

Constraint and contact components keep showing up as prefab overrides, even though nothing has changed. There are no properties highlighted as changed, even in debug mode. This gets very annoying trying to keep prefabs clean and organized.

For times where a VRCObjectSync might be out of sync with its identical counterpart on other clients, and maybe says "No Samples" in Debug Menu 8 (a mystery state that no one seems to know about), either because of a bug or some unusual world setup, but VRChat doesn't know it's out of sync because it only seems to update each VRCObjectSync for remote users when it has moved a significant-enough amount (a threshold that also might be good for creators to be allowed to decide per-world or per-object...), it would be nice to have a method I can just call on the owner that re-sends that VRCObjectSync's current state/data (or, at least, extremely similar data, if necessary) to make absolutely sure that everyone sees the same thing at that specific time. This would also be helpful because you can't move a VRCObjectSync for a non-owner even if it's in that "No Samples" state, because it'll often just go right back to where it thinks it should be immediately after I move it for that non-owner. Being able to force a VRCObjectSync to move in these scenarios would be invaluable.

If I enable VRC constraint-related components while editing a prefab (Prefab Mode) using a button provided by an editor extension, the isActive state does not persist—it is not saved and reverts after reopening or leaving Prefab Mode. This report was translated from Japanese.