<!--
{
  "documentType" : "article",
  "framework" : "RealityKit",
  "identifier" : "/documentation/RealityKit/ecs-entity-actions",
  "metadataVersion" : "0.1.0",
  "role" : "collectionGroup",
  "title" : "Entity actions"
}
-->

# Entity actions

Create simple, reusable actions that can change your app state, RealityKit scene, or animate an entity.

## Overview

Entity actions provide an easy way to change or animate parts of your scene,
while also allowing you to influence the changes with your app state.

For example, you can vary the size of an impulse you apply to an entity with [`ImpulseAction`](/documentation/RealityKit/ImpulseAction), play a sound at the end of an entity’s animation with [`PlayAudioAction`](/documentation/RealityKit/PlayAudioAction), or create a custom action that changes your app state.

## Topics

### Action management

[`EntityAction`](/documentation/RealityKit/EntityAction)

A protocol that defines an action for an entity.

[`ActionAnimation`](/documentation/RealityKit/ActionAnimation)

Defines an an action animation.

[`ActionEntityResolution`](/documentation/RealityKit/ActionEntityResolution)

Options available to determine the resolution method for a target entity in an action.

[`ActionHandlerProtocol`](/documentation/RealityKit/ActionHandlerProtocol)

The base protocol for action handlers.

### Action events

[`ActionEvent`](/documentation/RealityKit/ActionEvent)

The structure returned to all action event handlers.

[`AnimationState`](/documentation/RealityKit/AnimationState)

The concretely typed animation state structure.

[`ActionEventType`](/documentation/RealityKit/ActionEventType)

A set of events that an action responds to.

[`ActionEventDefinition`](/documentation/RealityKit/ActionEventDefinition)

Defines an action event interval, and any associated parameters.

[`AnimationStateProtocol`](/documentation/RealityKit/AnimationStateProtocol)

The protocol representing the current animation state of an action animation.

### Built-in actions

[`BillboardAction`](/documentation/RealityKit/BillboardAction)

An action that animates the blend factor of an entity’s billboard component.

[`EmphasizeAction`](/documentation/RealityKit/EmphasizeAction)

An action that performs an animation to call attention to an entity.

[`FromToByAction`](/documentation/RealityKit/FromToByAction)

An action that starts, stops, or increments by a specific value.

[`ImpulseAction`](/documentation/RealityKit/ImpulseAction)

An action that applies an impulse to the physics body at its center of mass when
played as an animation.

[`OrbitEntityAction`](/documentation/RealityKit/OrbitEntityAction)

An action which animates the transform of an entity to revolve around a specified pivot entity.

[`PlayAnimationAction`](/documentation/RealityKit/PlayAnimationAction)

An action that plays an animation on the given target entity with a range of playback options.

[`PlayAudioAction`](/documentation/RealityKit/PlayAudioAction)

An action which plays an audio resource on the given target entity.

[`SetEntityEnabledAction`](/documentation/RealityKit/SetEntityEnabledAction)

An action that enables or disables the targeted entity and its descendants when played as an animation.

[`SpinAction`](/documentation/RealityKit/SpinAction)

An action which animates the transform of an entity to rotate around a specified local axis.

### Behavior trees

[`BehaviorTreeComponent`](/documentation/RealityKit/BehaviorTreeComponent)

Manages which behavior tree is active for the component’s entity.

[`BehaviorTreeResource`](/documentation/RealityKit/BehaviorTreeResource)

An immutable representation of a behavior tree.

[`BehaviorTreeAction`](/documentation/RealityKit/BehaviorTreeAction)

A protocol that defines an action that a behavior tree action node can use.

[`BehaviorTreeActionHandler`](/documentation/RealityKit/BehaviorTreeActionHandler)

Behavior Tree-specific event handlers that allow an `ActionResult` to be returned from the handler.

[`ActionResult`](/documentation/RealityKit/ActionResult)

Status values that an action can report back to the animation system.


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)