World/Udon Bugs & Feature Requests

When Player B calls SetOwner on an object owned by PlayerA, both Player A and B temporarily have ownership, and then Player B loses ownership. As for the synced value, there is no problem because the values will eventually be synced, but it means that there will be a section where routines that work based on the IsOwner result will run on both Player A and B. This can be confusing and complicate matters for those who design based on the assumption that ownership holders are unique. Therefore, I would like to see you provide a SetOwner that works asynchronously as before (e.g. SetOwnerAsync)

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

I've been using VRCPhysBones for dynamic elements such as antennas and mud flaps on drivable vehicles since November, 2025 without issues, but some VRChat client update in January 2026 suddenly broke VRCPhysBones attached to vehicles in worlds, causing violent shaking when driving. PhysBones still behave normally in Unity Editor when testing using ClientSim, but when in game, all bones begin to violently shake back and forth, as if fighting against the linear motion of the vehicle. The issue was first discovered in a world that had been fully functional for weeks, when suddenly in January the stuttering began in all versions of the world. The vehicles use Rigidbody and VRCObjectSync at the root and Unity WheelColliders for wheels.

On the documentation page for Input Events ( https://creators.vrchat.com/worlds/udon/input-events/ ) "InputDrop" is said to be true for releasing the grip buttons on controllers other than vive wands or some WMR controllers. I've been doing a few tests with the input mappings to see how they behave between players using Vive wands and other controller types. So far, I've found that the "release grip" condition for InputDrop becoming true is only the case (for a single frame, which is good) when using Hand Tracking on Quest standalone, but I was unable to trigger it from releasing grip any other way. Oculus controllers - both from PCVR through SteamVR via Virtual Desktop, and on the standalone version - from my testing cannot fire InputDrop at all. Index controllers also can't fire it all either. I feel as though either this needs to be changed in the client or the documentation needs to be updated... With this in mind though, currently a usable workaround is to just do the "release grip" check on our own via Udon, using the InputGrab event and checking for False. P.S: I also found that the OnInputMethodChanged event always says SteamVR2 when playing from PCVR, regardless of the actual input type, but this was already reported in another post. Also, The input method for Hand Tracking on Android returns a value of 19, which is not documented as the highest value shown on the website is 18. My IDE says that it does exist however with an enum called "VRCInputMethod.Count" instead of using "VRCInputMethod.QuestHands"? Still strange.

I'm trying to add shadows to my world Test Pilots and it works fine on desktop mode but in VR I'm getting severe shadow acne. I've attached two images, one showing desktop and one showing VR. I have messed with the following settings (and there are sliders to change them in the world): Near/Far clipping plane Directional light's Bias and Normal Bias None of them seem to help much, so I'm wondering if there's an internal VR setting that has been overlooked that is causing this issue. My settings are as follows: Near: 0.05 (max allowed in VRC) Far: 50000 I realize these settings are extreme, but I can't see a reason why there'd be such a huge difference between VR and desktop. I've uploaded a barebones version of the world for testing at: https://vrchat.com/home/world/wrld_6a5d6107-25a1-4152-9eb2-0b110ae23432/info To see the issue go in VR and either fly up in the air using jump + left trigger OR click on the 'Teleport To Light Control' button and look towards the large grey structure. Note there is a day/night cycle in the world so sun angle may change if you stay too long. Hit the 'Set Day' button at spawn to freeze it. Issue has been observed on Index and Quest 3

Gravity and Kinematic flags on VRCObjectSync components don't sync correctly right now and also cannot be set correctly while holding the pickup. To set gravity or kinematic flags, VRChat added two new methods for us: https://udonsharp.docs.vrchat.com/vrchat-api/#vrcobjectsync (they are supposed to behave like a synced variable) There are two bugs related to this: ~ Bug 1: ~ All you need is to create a pickup that has no gravity and then toggle the gravity flag on the VRCObjectSync component with an external button after claiming ownership. Then you let different people in the world pick up the pickup and drop it (to show their own local state). In my tests, this resulted in a pickup where the gravity flag is wildly different on each client and only syncs occasionally or not at all. They would see the pickup drop on my end, but when they pick it up it has no gravity for them. ~ Bug 2: ~ All you need is to create a pickup that has no gravity and then toggle the gravity flag on the VRCObjectSync component in OnPickupUseDown() . In my tests, this resulted in a pickup where the gravity stays enabled after the first OnPickupUseDown() and I am unable to turn gravity off again. To check gravity, the pickup is dropped. You can also just test it out here: Right setup: Bug 1 / Left setup: Bug 2 https://vrchat.com/home/world/wrld_9cefd5ec-4492-43c5-8cd3-05036c494556 Additional note: Since we only got a setter and not a getter method, we are left in the dark here when it comes to analyzing the problem. Reading out the local rigidbody state doesn't give us access to the real synced state. A getter method should be added.

While local strings allow storing from range \u0000 to \uffff , any synced strings are forcefully encoded with UTF-16, making any characters within range \ud7fff to \udfff be truncated to \ufffd . It seems like internal serializer or deserializer is treating all strings as UTF-16 encoded texts, no matter what their purpose is. I do know strings require terminators like \0 to be memory safe, or for some other features like support for emojis via utilizing surrogate pairs, but in raw memory side, string can be treated just like other containers, and I'm utilizing for maximum productivity and memory&network efficiency. (For example, treating each character as 2 bytes, or even go further, 4 hexadecimal numbers) I see this becomes important, due to VRChat's network bandwidth limitations and Udon's performance compared to normal C# codes. Just like gameboy-era old games did, I need to squeeze out all the possible bytes to make the code both performance and network-efficient. Maybe treat string just like byte[] when serialized? or maybe adding a special attributes like NonEncoded to the string variable so that the variable is treated just like another data container?

I have encountered a problem related to Unity's DSP chain and Udon. I am planning to create an audio focused world, where I need to implement a custom DSP algorithm on audio that can respond to player behavior/controls in real-time. In the native Unity Mono framework, I can insert custom effects into the audio DSP chain by implementing the OnAudioFilterRead method in MonoBehaviour (see https://docs.unity3d.com/ScriptReference/MonoBehaviour.OnAudioFilterRead.html ). In the UdonSharp documentation, I found that there is a method stub for OnAudioFilterRead in Unity events (see https://udonsharp.docs.vrchat.com/events/ ), so I should be able to implement it. However, it does not work in my Unity setup. I also saw a post on Canny mentioning that a component called OnAudioFilterReadProxy should be automatically added to the object if OnAudioFilterRead is implemented (See: https://vrchat.canny.io/udon/p/order-of-onaudiofilterreadproxy ), but this is not happening on my end. Any idea what could be going wrong with my script or configuration? Or it is a bug? My test code is like the following: using UdonSharp; using UnityEngine; using VRC.SDKBase; using VRC.Udon; public class SimpleSineGenerator : UdonSharpBehaviour { [SerializeField, Range(0, 1)] private float amplitude = 0.5f; [SerializeField] private float frequency = 261.62f; private double phase = 0; private double sampleRate = 48000; public void Update() { // verify that the script is running transform.Rotate(Vector3.up, 90f * Time.deltaTime); } public void OnAudioFilterRead(float[] data, int channels) { // DSP code double phaseIncrement = 2 * Mathf.PI * frequency / sampleRate; for (int i = 0; i < data.Length; i += channels) { phase += phaseIncrement; if (phase > 2 * Mathf.PI) { phase -= 2 * Mathf.PI; } float value = amplitude * Mathf.Sin((float)phase); for (int j = 0; j < channels; j++) { data[i + j] = value; } } } }

Udon's OnVideoPause and OnVideoPlay are not called. Using several multi-function video players provided by volunteers, I attached the following script to the same object as VRC Unity Video Player or VRC AVPro Video Player and tried to play/pause/resume/stop/loop the video player. OnVideoEnd, OnVideoError, OnVideoLoop, OnVideoStart, and OnVideoReady are called, but OnVideoPause and OnVideoPlay are not. ----------------------------------------------------- using UdonSharp; using UnityEngine; using VRC.SDK3.Components.Video ; public class VideoPlayerDebugLoger : UdonSharpBehaviour { public override void OnVideoEnd() { Debug.Log("---------------- Video Ended"); } public override void OnVideoError(VideoError videoError) { Debug.Log("---------------- Video Error: " + videoError); } public override void OnVideoLoop() { Debug.Log("---------------- Video Loop"); } public override void OnVideoPause() { Debug.Log("---------------- Video Paused"); } public override void OnVideoPlay() { Debug.Log("---------------- Video Played"); } public override void OnVideoReady() { Debug.Log("---------------- Video Ready"); } public override void OnVideoStart() { Debug.Log("---------------- Video Started"); } }

Converting an enum to an int in a method call which takes a DataToken as argument crashes at runtime with error Cannot retrieve heap variable of type 'Int32' as type 'DataToken' . Converting it beforehand does not crash. For example, this crashes: DataList dataList = new DataList(); AnEnum anEnumState = AnEnum.AState; dataList.Add((int)anEnumState); Whereas this doesn't crash: DataList dataList = new DataList(); AnEnum anEnumState = AnEnum.AState; int anEnumStateInt = (int)anEnumState; dataList.Add(anEnumStateInt);