SDK Bug & Feature Requests

The UdonSharp/UtilityScripts folder and it's contents are recreated upon Recompile or Asset Reload for some world projects. Data loss can occur if a creator modified or added content to the existing scripts. This also changes their GUIDs which creates unnecessary changes on worlds shared via git. Related: https://feedback.vrchat.com/sdk-bug-reports/p/vrcdefaultworldscene-sometimes-is-recreated-upon-project-launch

Summary: The VRChat SDK is causing Unity to falsely detect prefab overrides when no actual changes have been made. This issue occurs both during general SDK activity (not just when opening the SDK tab) and specifically when uploading or updating avatars. It often flags the Avatar Descriptor component as "changed," even when untouched. Steps to Reproduce: Open a Unity project with VRChat SDK (SDK3 - Avatars). Create or load a prefab-based avatar. Upload or re-upload the avatar via the SDK. After upload completes, observe that the avatar prefab now shows "Unapplied Overrides" in the inspector. Open the prefab and inspect the VRC_AvatarDescriptor — Unity claims it's been modified, even though no changes were made. Expected Behavior: Uploading or interacting with the SDK should not trigger false prefab overrides when no values were changed. Avatar Descriptor and other components should remain untouched unless explicitly edited. Actual Behavior: Prefab instances are flagged with "Unapplied Overrides" after uploading or interacting with the SDK. The VRC_AvatarDescriptor component is frequently shown as modified, despite no visible differences. These overrides appear without user input, leading to confusion and unnecessary prefab management. Known Triggers: Uploading or re-uploading avatars. SDK interactions during project use (not limited to opening the SDK tab). SDK updates that introduce new systems like (often re-introduce the bug): PhysBones, Constraints, Per-platform Avatar Overrides Impact: Disrupts normal Unity workflow and prefab integrity. Forces creators to manually check or apply overrides to maintain consistency. (Sometimes not even working and getting stuck in an override change loop) Risk of unintentionally applying unwanted changes or overwriting important prefab data. Time-consuming and frustrating for creators managing large or complex prefabs. Additional Notes: This issue has persisted across multiple SDK updates and is easily reproducible. It appears tied to how the SDK modifies or refreshes component data internally. Given how fundamental prefabs are to Unity projects, this issue should be considered a high-priority bug — especially for avatar creators relying on clean and reliable prefab behavior.

With SDK version 3.7.5 several settings were migrated from the static class VRCSettings , existing within the VRCSDKBase-Editor.dll library provided alongside the SDK to VRCPackageSettings , the change also included a refactor of the class, introducing a static property Instance , used to get or create an instance of the class, an instance is attempted to be created by the PerceptualPostProcessor as DPID settings were part of the migration, however this fails because of a null exception: VRCPackageSettings.Instance.dpidMipmaps within PerceptualPostProcessor executes VRCPackageSettings.Instance_get VRCPackageSettings._instance is null so Create() is called, which calls Load() Load() and calls within it, including EnsurePathExists() expect GetPath() to not be null, causing a null exception when it is because GetPath() calls GetPathFromType(GetType()) which calls UnityEditor.PackageManager.PackageInfo.FindForAssembly(t.Assembly) and returns null when executed by a worker process, GetPathFromType then returns null (a comment assumes this would only occur when the SDK is not located within the Packages folder) but this execution path was seemingly never tested and so methods that expect valid strings such as Directory.CreateDirectory within EnsurePathExists() throw null exceptions. Simply resolving the null exceptions is not enough as the current implementation would cause Load() to not load any data when it's meant to, leading to VRCPackageSettings.Instance to contain default values when executed by worker processes ( AssetDatabase.IsAssetImportWorkerProcess() ), you cannot simply abort execution because that invalidates the use of Parallel Import and would cause textures marked as "dirty" to not actually be updated to have mipmaps re-generated, a proper solution leading to the same settings file must be implemented, the whole dependency on the assembly's package info seems extreme. This can be easily reproduced on any 3.7.5+ project with Parallel Import enabled (Project Settings -> Editor, mine is configured with 8 desired workers and 2 on standby) by enabling/disabling "Override Kaiser mipmapping" in the SDK settings.

Since 3.10 came out the option for "mobile multiply/additive" are broken!! across all SDK versions!! They work in unity and the sdk allows us to select them, but they break in game! I AM aware "vrc does not support transparency on quest" yet myself and MANY other creators have been using these shaders for at least over a year and have had NO issues until now!! I ask that you please look into this as MANY of us cannot create for quest until you fix it! : /

Problem : The default scale of (100, 100 , 1) does not line up with Unity grid, and shows the lines at a meaningless arbitrary interval. Cause : This is due to the default GridFloor_udon material has a tiling of 8 by 8. Solution : Rescale the Floor object to (64, 64, 1) will line up the texture with Unity grid perfectly.

UdonSharp reports Utilities.ShuffleArray (the T type) as not exposed to Udon, despite it working just fine in an UdonGraph program. The int[] version of this function does compile in UdonSharp.

This is important for Asset searching. By default, Unity hides any and all assets that are located inside Packages. In order to make sure searching for Assets from areas such as Inspector fields to show items located inside the SDK by default (such as Menu Icons, Prefabs, etc.), the following line must be added to the package.json: "hideInEditor": "false" This will ensure this button (see screenshot) doesn't need to be toggled to find example assets in the SDK.

When we uploaded multiple avatars in a row relatively quickly, we encountered an issue where the upload process would freeze without any error message shown on the console or in the log files. This issue comes from two main causes: Firstly, the VRChat SDK silently ignores exceptions that occur in VRC_SdkBuilder.RunExportAvatarBlueprint . The catch clauses has comment // Errors are handled by the error callback , but most of the exceptions do not initiate error callback, including this one. Secondly, the VRChat SDK does not handle the exception occurred when trying to delete the last uploaded .vrca file. Removing the last uploaded .vrca file is not a critical step in the upload process, so it should not cause upload to freeze. However, currently, if the deletion fails, the upload process will not continue, leading to a freeze. When we replaced catch clauses to catch (Exception e) { Debug.LogError(e); } , we were able to see the following error message in the console: System.IO.IOException: The process cannot access the file 'C:\Users\****\AppData\Local\Temp\****\****\637e8e6c-8eb6-4cd2-a651-241fb7aa6ed3.vrca' because it is being used by another process. at System.IO.FileSystem.DeleteFile (System.String fullPath) [0x0001a] in <27124aa0e30a41659b903b822b959bc7>:0 at System.IO.File.Delete (System.String path) [0x00014] in <27124aa0e30a41659b903b822b959bc7>:0 at VRC.SDK3.Builder.VRCAvatarBuilder.ExportCurrentAvatarResource (UnityEngine.Object avatarResource, System.Boolean testAsset, System.Boolean buildAssetBundle, System.String& avatarPrefabPath, System.Action`1[T] onProgress, System.Action`1[T] onContentProcessed) [0x003bc] in <81261fc1c1e94d15bda5671000ac0e16>:0 at VRC.SDK3.Builder.VRCAvatarBuilder.ExportAvatarBlueprint (UnityEngine.GameObject externalReference) [0x00021] in <81261fc1c1e94d15bda5671000ac0e16>:0 at VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder.Build (UnityEngine.GameObject target, System.Boolean testAvatar) [0x0040b] in .\Packages\com.vrchat.avatars\Editor\VRCSDK\SDK3A\VRCSdkControlPanelAvatarBuilder.cs:2600 UnityEngine.StackTraceUtility:ExtractStackTrace () UnityEngine.DebugLogHandler:LogFormat (UnityEngine.LogType,UnityEngine.Object,string,object[]) UnityEngine.Logger:Log (UnityEngine.LogType,object) UnityEngine.Debug:LogError (object) VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder/<Build>d__132:MoveNext () (at ./Packages/com.vrchat.avatars/Editor/VRCSDK/SDK3A/VRCSdkControlPanelAvatarBuilder.cs:2605) System.Runtime.CompilerServices.AsyncMethodBuilderCore/MoveNextRunner:InvokeMoveNext (object) System.Threading.ExecutionContext:RunInternal (System.Threading.ExecutionContext,System.Threading.ContextCallback,object,bool) System.Threading.ExecutionContext:Run (System.Threading.ExecutionContext,System.Threading.ContextCallback,object,bool) System.Runtime.CompilerServices.AsyncMethodBuilderCore/MoveNextRunner:Run () System.Threading.Tasks.SynchronizationContextAwaitTaskContinuation/<>c:<.cctor>b__7_0 (object) UnityEngine.UnitySynchronizationContext/WorkRequest:Invoke () UnityEngine.UnitySynchronizationContext:Exec () UnityEngine.UnitySynchronizationContext:ExecuteTasks () When we disabled the real-time protection of the antivirus software for the temporary folder, the upload process worked as expected without freezing. Therefore, we conclude that the issue is related to antivirus software holding a handle on the last uploaded .vrca file, which prevents it from being deleted.

My seat trigger colliders are inside of a physical hull collider. The hull is on a custom layer called PhysicCollider and I use the "Interact Passthrough" setting to make it transparent to interaction. Live I can interact with the seats. That was uploaded with SDK 3.5.0. But when I upload my world with SDK 3.6.0, the interaction isn't possible anymore. I have to crawl to reach the seat collider inside. I guess, that feature broke with the layer changes in SDK 3.6.0. The first two images shows live SDK 3.5.0 vs my testworld SDK 3.6.0.

There was a previous canny post where I addressed this issue when Toon Standard was very new, and I was told there that this issue would be fixed. I cannot find the old post and the issue has not been fixed throughout many updates to the SDK. The reflectance property of the Specular section should only be applied based on the Smoothness map, or should get it's own map.