表情
「表情」（Expressions），是在 VRChat 中的角色（Avatar）功能之一，其由用戶自訂的選單所組成，可讓用戶在角色上啟用各種動作或切換功能，旨在以靈活且方便的方式快速存取角色的獨特功能。
更多資訊請參閱關於角色的創作者文件。
表情選單
遊戲內的表情選單，可透過動作選單（Action Menu）存取，也可透過快速選單（Quick Menu）與主選單（Main Menu）中的表情標籤頁存取。這種操作方式適用於所有平台的 VRChat。角色表情的變化會同步給同一平台上的其他用戶，並可設定跨平臺同步。
SDK 中的表情
表情功能可透過 VRChat SDK 中的各種參數進行編輯。
基礎表情
當未設定任何表情功能時，系統會自動為角色加入包含基礎動畫的預設表情選單，其中包含以下動畫：
- 揮手（Wave）
- 鼓掌（Clap）
- 指向（Point）
- 歡呼（Cheer）
- 跳舞（Dance）
- 後空翻（Backflip）
- 死亡（Die）
- 悲傷（Sadness）
自訂表情
若要新增自訂表情，請先在 Unity 中建立 Expression Menu（表情選單）資產與 Expression Parameters（表情參數）資產，然後在 VRChat Avatar Descriptor 的 Expressions 區段中指派這些資產。Expression Menu 用於定義哪些控制項會顯示於遊戲內選單，而 Expression Parameters 則用於定義這些控制項所變更之數值的名稱、類型、預設值，以及同步行為。
每個自訂參數都可以設定是否 Saved（儲存）及 Synced（同步）。已同步的自訂參數會計入角色的 256 位元同步預算，而單一角色最多可定義 8192 個自訂參數。此資產中的參數也可以由 Contact Receiver、Parameter Driver、PhysBone 以及 OSC 進行變更。
SDK 也提供了一個 Default Parameters（預設參數）按鈕。按鈕會還原 VRChat 預設 AV3 控制器所使用的三個別名參數：VRCEmote、VRCFaceBlendH 與 VRCFaceBlendV。
控制
每個頁面最多可建立 8 個控制項。建立控制項時，可選擇以下類型：
- Button（按鈕）：按下時瞬間設定指定數值，並在 VRChat 傳送變更後立即自動重設。
- Toggle（切換）：啟用時設定指定數值，停用時則重設該數值。
- Sub Menu（子選單）：下設另一個表情選單，並可選擇在該子選單開啟期間設定特定參數。
- Two Axis Puppet（雙軸控制）：透過水平與垂直輸入控制兩個浮點數參數，通常範圍為
-1.0至1.0。 - Four Axis Puppet（四軸控制）：控制四個浮點數參數，分別對應四個方向，通常範圍為
0.0至1.0。 - Radial Puppet（環形控制）：以環狀滑塊控制一個浮點數參數，範圍為
0.0至1.0。
控制選單範例
當你向不同方向移動搖桿、觸控板或滑鼠時，將會改變其動畫參數，以此來表現不同表情，或在不同表情之間進行混合（例如「開心」與「驚訝」）。任何參數都可以透過此選單進行控制。
你可以在任一隻手上開啟一個選單（或同時在兩隻手上開啟）。預設情況下，可透過快速撥動來選擇選項；你也可以在動作選單設定中改為使用扳機鍵進行選擇。若要返回表情選單的上一層，請按下扳機鍵。
當屬於控制類型的控制項被開啟時，VRChat 會使用較快速的 IK 同步模式即時同步其數值。控制項關閉後，當前數值會維持不變，直到再次被修改為止。
表情參數
表情參數（Expression Parameters）可透過表情選單、Contact Receiver、OSC、Parameter Driver 或 PhysBone 元件來控制角色功能。這些參數接著會對應至角色 FX、手勢（Gesture）或動作控制器中的 Animator Controller 參數。
設定
Each entry in the Expression Parameters asset stores:
- Name, which must match the Animator parameter name exactly.
- Type, which can be
Bool,Int, orFloat. - Default, which is used when the avatar is reset.
- Saved, which controls whether the value persists between sessions.
- Synced, which controls whether the value is sent to other users.
By default, custom parameter sync uses VRChat's Playable sync mode. Puppet controls temporarily use faster IK sync while they are actively open.
Built-in parameters
VRChat also provides built-in Animator parameters. These do not need to be added to the Expression Parameters asset, and they do not count toward the custom parameter budget.
Built-in parameters are read-only. They are added directly to a playable layer's Animator Controller by name, and VRChat updates them automatically at runtime. They are not set on sub-animators, only on playable-layer animators.
Additional built-in parameters include:
Viseme(Int) — Set by lip sync from0(silence) to14(the "u" vowel) when the Avatar Descriptor's Lip Sync is set to Viseme Blend Shape or Viseme Parameter Only.Voice(Float) — Perceived microphone volume from0.0to1.0, affected by distance and earmuff settings.VelocityX,VelocityY,VelocityZ,VelocityMagnitude(Float) — Movement speed in m/s along each axis and total magnitude. Locally, playspace movement does not count; remotely, it does.Upright(Float) —0when prone,1when standing.Grounded(Bool) — Whether the user is touching the ground.MuteSelf(Bool) — Whether the user's microphone is muted.Earmuffs(Bool) — Whether the user has earmuffs enabled.IsOnFriendsList(Bool) — Whether the viewer is friends with the avatar's wearer (shows False locally).ScaleFactor,ScaleFactorInverse,EyeHeightAsMeters,EyeHeightAsPercent(Float) — Scaling-related parameters for avatar scaling.EyeHeightAsMetersis recommended for scale-aware systems because it is linear and does not depend on upload height.
Each built-in parameter has a sync type determining when it is sent to remote users: IK for tracking-derived values (gestures, velocity, grounded), Speech for voice-related values (viseme, voice), Playable for user-state values (mute, earmuffs, tracking type, scale), or None for local-only values (IsLocal, PreviewMode).
Network synchronization
Only synced expression parameters and certain built-in parameters are sent over the network. The full list of data sent for each avatar includes:
- IK targets — Head, jaw, and hands for desktop and 3-point tracking; additionally hip and feet for full-body tracking. Index controller users also sync finger positions.
- Synced expression parameters — Only parameters marked as Synced are transmitted. Values are quantized: Int values sync in the range 0–255, Float values sync as multiples of 1/127 between −1 and 1, and Bools sync as true or false.
- Built-in VRC parameters — Including gestures, velocity, voice, and other runtime parameters.
- PhysBones — Pose position data is sent to late joiners.
For reliable late-joiner support, a recommended pattern is to split animator logic using the IsLocal parameter: local-side layers handle contacts, parameter drivers, and all logic, then set synced parameters, while remote-side layers only read those synced parameters to play the correct visualization.
Gestures and facial expressions
The built-in GestureLeft and GestureRight parameters identify the user's hand gesture, while GestureLeftWeight and GestureRightWeight expose analog trigger pressure. On humanoid avatars, the Gesture playable layer is commonly used for hand poses, while facial expressions are often driven from the FX layer with blendshapes, material properties, or other non-humanoid animations.
On tracked controllers where finger tracking overrides animation by default, creators can use a Tracking Control state behavior to switch the relevant fingers from Tracking to Animation when needed.
Expression Parameter Mismatching
Expression Parameter Mismatching refers to the practice of using different parameter types between your Expression Parameters and your local Animator Controller parameters. While it is recommended to keep parameter types consistent, mismatching is supported and the system will convert values between types according to specific rules. This can be useful in certain advanced setups. The same conversion behavior can also be used with built-in VRChat Animator parameters.
Unity's Animator system uses floats on the backend for all parameter types, while VRChat stores synced custom parameters in compact network-friendly formats. The user interface in Unity and the VRCSDK lets creators choose parameter types for convenience, but under the hood, value conversion is possible. This means that parameters are not being cast in the C# sense, but rather mismatched across systems. This behavior is also supported by popular tools such as Av3Emulator and Gesture Manager.
Expression Parameter Bool
| Type | Expression Bool = False | Expression Bool = True |
|---|---|---|
| Bool → Bool | Bool = False | Bool = True |
| Bool → Int | Int = 0 | Int = 1 |
| Bool → Float | Float = 0.0 | Float = 1.0 |
Expression Parameter Int
| Type | Behaviour |
|---|---|
| Int → Bool | Any Int value that isn't 0 sets bool to True |
| Int → Int | Expected Behaviour |
| Int → Float | Straight Conversion: e.g. Int = 2 → Float = 2.0 |
Expression Parameter Float
| Type | Behaviour |
|---|---|
| Float → Bool | Any Float value that isn't 0 sets bool to True |
| Float → Int | Rounded Conversion: ≥0.5 → 1 ; <0.5 → 0 |
| Float → Float | Expected Behaviour |
Resources
- Avatar 3.0 Hub world on VRChat
- Expression Menu and Controls on Creator Docs
- Action Menu - Expression Menu on Creator Docs
- Animator Parameters on Creator Docs
- Playable Layers on Creator Docs
- State Behaviors on Creator Docs
