VRChat Technical Notes

A comprehensive list of C# features available in UdonSharp development and limitations imposed by the Udon VM. Covering variables, control structures, methods, and unsupported features like generics and interfaces.

UdonSharp Lifecycle: Understanding Start, Update, and Interact

The event system that controls script execution timing. Learn the roles and implementation patterns of major lifecycle events including Start, Update, and Interact.

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Mastering User Input Detection: Utilizing Interact and Input Events

Input detection methods for player interaction with worlds. Learn implementation patterns for Interact events, VRChat Input Events, and keyboard/VR controller input.

Variables and Data Types in UdonSharp: Basics of int, float, and GameObject

The fundamentals of UdonSharp programming: variables and data types. From basic types (int, float, bool, string) to Unity types (Vector3, GameObject, Transform) explained with examples.

Leveraging Attributes: Using UdonSynced, Header, and Range

A list and usage guide for attributes available in UdonSharp. Synchronization with [UdonSynced], Inspector organization with [Header][Tooltip][Range], and improving development efficiency.

Methods and Custom Events: Script Communication with SendCustomEvent

Code reuse and inter-script communication methods. Learn method definitions, SendCustomEvent, SendCustomNetworkEvent, and delayed execution (SendCustomEventDelayedSeconds).

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Complete Guide to Player Events: Detecting Join, Leave, and Respawn

Events for detecting player state changes in worlds. Implementation methods for OnPlayerJoined/Left, OnPlayerRespawn, OnAvatarChanged, and pickup-related events.

Introduction to Network Synchronization: Understanding Ownership and UdonSynced

The fundamentals of network synchronization at the core of VRChat multiplayer. Object ownership, [UdonSynced] variables, and the mechanism of data sharing through RequestSerialization.

Respawning Fallen Players: Bring Them Back with an Out-of-Bounds Trigger

Gimmicks2026-05-22

A practical example of automatically returning players who fall through gaps in your world to a safe point. A beginner-friendly guide to a fall-recovery gimmick built with just a VRC Scene Descriptor spawn setup and an out-of-bounds trigger plus TeleportTo.

Implementing Synced Buttons: Local, Toggle, and One-Time Patterns

A collection of button implementation patterns for world creation. How to create local buttons, toggle switches synced across all players, and one-time-only buttons.

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Creating a Mirror System: ON/OFF Toggle and Quality Settings

Essential mirror control methods for VRChat worlds. VRCMirrorReflection on/off toggle, Reflect Layers, and quality preset implementation via resolution.

Creating Door Gimmicks: Synced Automatic and Manual Door Implementation

Implementation methods for doors as fundamental dynamic objects. Automatic doors that open when approached, manual doors that open/close on click, animation integration and network synchronization.

Introduction to Pickup Objects: Creating Grabbable and Usable Items

Implementing items that players can pick up and manipulate. VRCPickup component, OnPickup/OnDrop/OnPickupUseDown events, and state synchronization methods.

Creating Teleporters: How to Instantly Move Players

Implementation of teleporters and portals for comfortable world navigation. From basic teleportation using VRCPlayerApi.TeleportTo to portals with synced visuals.

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Implementing Stations: Chairs, Vehicles, and Sittable Objects

Implementing functionality to seat players at fixed positions. VRCStation component setup, enter/exit events, and application to vehicles.

Optimization with VRCObjectPool: Managing Bullet and Effect Creation