World/Udon Bugs & Feature Requests

Log the bool "value" argument for InputUse. Click your mouse and release. Expected: receive "True" once, receive "False" once Actual:

Environment: Unity version: 2022.3.22f1 VRChat SDK Worlds: 3.10.3 VRChat SDK Base: 3.10.3 UdonSharp included with SDK Project uses Prefab Mode / PrefabStage with UdonSharpBehaviour components YamaPlayer package present: net.kwxxx.yama-stream 1.5.18 Observed: When opening or editing prefabs containing UdonSharpBehaviour components in Prefab Mode, Unity logs repeated ArgumentNullException errors from OdinSerializer UnitySerializationUtility. Error: ArgumentNullException: Value cannot be null. Parameter name: unityObject VRC.Udon.Serialization.OdinSerializer.UnitySerializationUtility.SerializeUnityObject(...) UdonSharp.UdonSharpBehaviour.UnityEngine.ISerializationCallbackReceiver.OnBeforeSerialize() and similarly: UnitySerializationUtility.DeserializeUnityObject(...) UdonSharp.UdonSharpBehaviour.UnityEngine.ISerializationCallbackReceiver.OnAfterDeserialize() Trigger: Open a prefab containing UdonSharpBehaviour in Prefab Mode Move a child object or let PrefabStage autosave run Errors repeat, sometimes dozens/hundreds per save Expected: PrefabStage autosave should not throw if a Unity pseudo-null UdonSharpBehaviour or serialized target is encountered. It should skip invalid objects or handle UnityEngine.Object pseudo-null safely. Additional finding: For diagnosis only, I temporarily tested a local guard around the SDK serialization path. The test indicated that the affected object was not a normal C# null reference, but behaved as null through Unity's overloaded UnityEngine.Object null comparison. With that guard in place, the exception stopped. I am not using this as a permanent workaround and do not intend to publish content with a modified SDK. This observation is included only to help identify the likely failure path. Additional observation: I have encountered this issue twice. In both cases, once the issue started occurring in the project, checking out older repository commits did not reliably make the issue disappear. This suggests that the trigger may involve Unity Library/cache/generated SDK state or some project-local serialized state, not only the currently checked out asset files.

Components sometimes "break" in Unity 2022. They are collapsed, and expanding them reveals nothing. It affects different types of components, i.e. UdonBehaviours or MeshRenderers. It can be fixed by selecting a different game GameObject. In my world projects, it's caused by the following error: ArgumentNullException: Value cannot be null. Parameter name: unityObject VRC.Udon.Serialization.OdinSerializer.UnitySerializationUtility.SerializeUnityObject (UnityEngine.Object unityObject, VRC.Udon.Serialization.OdinSerializer.SerializationData& data, System.Boolean serializeUnityFields, VRC.Udon.Serialization.OdinSerializer.SerializationContext context) (at ./Packages/com.vrchat.worlds/Runtime/Udon/Serialization/OdinSerializer/Unity Integration/UnitySerializationUtility.cs:1031) UdonSharp.UdonSharpBehaviour.UnityEngine.ISerializationCallbackReceiver.OnBeforeSerialize () (at ./Packages/com.vrchat.worlds/Integrations/UdonSharp/Runtime/UdonSharpBehaviour.cs:272) UnityEditor.EditorApplication:Internal_CallGlobalEventHandler()

When attempting to use String Loading to download a file through Udon, if for whatever reason the download never completes, neither the success or error functions will be called without any indicator or way to know what's going on. This is different with Image Loading where there's a progress float that tells us the progress of the download. https://creators.vrchat.com/worlds/udon/string-loading https://creators.vrchat.com/worlds/udon/image-loading This causes problems in practice because Udon will be waiting for a callback that will never be called, and we don't know if it's because of slow internet or a failure of the request that hasn't and will never thrown any error. Requesting parity for String Loading to be able to get the download progress, both so we can display the state to users as well as handle the scenario by providing fallback logic.

This was reported as fixed in 2024.4.1p3 but it looks like the problem crept back in and exists in SDK 3.8.2 / 2025.3.1 (haven't tested any other versions). Since the previous canny was closed out as complete, thought I'd open a new one. Prior bug report on this issue: https://feedback.vrchat.com/udon/p/braces-inside-strings-in-vrcjson-can-fail-to-deserialize // This works if(VRCJson.TryDeserializeFromJson("\"{\"data\":\"test\"}", out DataToken token2)) Debug.LogError("Failed to deserialize JSON"); else Debug.Log("Successfully deserialized JSON"); // This fails. Only difference is the braces after the word test in the JSON string. Number of braces or their configuration doesn't seem to make a difference. if(VRCJson.TryDeserializeFromJson("{\"data\":\"test{}\"}", out DataToken token1)) Debug.LogError("Failed to deserialize JSON"); else Debug.Log("Successfully deserialized JSON"); Thanks! -Tea

Repro: var bounds = new Bounds( Vector3.zero , Vector3.one ); Debug.Log("Bounds: " + bounds.size); bounds.Expand(100f); Debug.Log("Bounds: " + bounds.size);

Vector3Int.Clamp doesn't change anything when I tested it with this simple U# code: https://gist.github.com/nuip/9f249bcdd1f800483c1e971cf9e1a102

When using Immobilize(), the whole point is that the player can't move anymore, e.g. so that users can type text on the keyboard without accidently moving when hitting WASD etc. Currently, only WASD is blocked correctly, but a lot of other movements are not blocked. Those are jumping, crouching, laying down. Please add those to the blocked movements so that players are not annoyed by accidental movement when they type text into an input field.

Child GameObjects appear brighter than expected under the following conditions: The parent Canvas has "Vertex Color Always In Gamma Color Space" enabled. One of the following applies to a child GameObject: (a) It has no SuperSampledUI material assigned. (b) It has a SuperSampledUI material assigned with a custom _Tint value, and the GameObject is disabled before building the world. In these cases, it appears that a default SuperSampledUI material is assigned to the UI element at runtime, with _Tint = (1, 1, 1, 1). This results in increased brightness compared to the expected color output. In the Unity Editor, colors appear correctly both in Edit mode and when entering Play mode. The issue only manifests after building the world.

If you use VRCPlayerApi.SetVoiceDistanceFar() or VRCPlayerApi.SetVoiceDistanceNear() The the value seems to get clamped to a maximum of 10000. I would like the maximum range to be as high as possible for stuff like aircraft radios.