# ActionAnimation Defines an an action animation. ``` struct ActionAnimation where ActionType : EntityAction ``` ## Overview The definition is used to generate an action animation based `AnimationResource` that can then be played by calling [`playAnimation(_:transitionDuration:blendLayerOffset:separateAnimatedValue:startsPaused:clock:handoffType:)`](/documentation/RealityKit/Entity/playAnimation(_:transitionDuration:blendLayerOffset:separateAnimatedValue:startsPaused:clock:handoffType:)) Action animations can be used to perform operations in lock-step with playback. Actions can be grouped or sequenced with pre-existing animation resources or be stand alone. For example an action that triggers sound can be grouped with a sampled animation to trigger sound effects at the appropriate times during playback. See: [`group(with:)`](/documentation/RealityKit/AnimationResource/group(with:)) Stand alone action animations can animate target values using RealityKit’s animation engine with cross fade, and additive compositing support. (See: [`AnimationStateProtocol`](/documentation/RealityKit/AnimationStateProtocol)) ## Topics ### Initializers [`init(for: ActionType, events: [ActionAnimation.EventDefinitionType], name: String, bindTarget: BindTarget?, blendLayer: Int32, repeatMode: AnimationRepeatMode, fillMode: AnimationFillMode, trimStart: TimeInterval?, trimEnd: TimeInterval?, trimDuration: TimeInterval?, offset: TimeInterval, delay: TimeInterval, speed: Float)`](/documentation/RealityKit/ActionAnimation/init(for:events:name:bindTarget:blendLayer:repeatMode:fillMode:trimStart:trimEnd:trimDuration:offset:delay:speed:)) Constructs an action animation that generates events at user defined times. ### Instance Properties [`var action: ActionType?`](/documentation/RealityKit/ActionAnimation/action) The action for which an animation is being defined. [`var bindTarget: BindTarget`](/documentation/RealityKit/ActionAnimation/bindTarget) [`bindTarget`](/documentation/RealityKit/AnimationDefinition/bindTarget) is not used. [`var blendLayer: Int32`](/documentation/RealityKit/ActionAnimation/blendLayer) [`blendLayer`](/documentation/RealityKit/AnimationDefinition/blendLayer) is not used. [`var delay: TimeInterval`](/documentation/RealityKit/ActionAnimation/delay) An amount of time that lapses before the animation plays. [`var duration: TimeInterval`](/documentation/RealityKit/ActionAnimation/duration) The elapsed time for one complete rotation. [`var eventDefinitions: [ActionEventDefinition]`](/documentation/RealityKit/ActionAnimation/eventDefinitions) The event interval definitions, and their associated parameter data. [`var fillMode: AnimationFillMode`](/documentation/RealityKit/ActionAnimation/fillMode) An option that determines which data displays outside of the normal duration. [`var name: String`](/documentation/RealityKit/ActionAnimation/name) A textual name for the animation. [`var offset: TimeInterval`](/documentation/RealityKit/ActionAnimation/offset) The time, in seconds, at which the animation begins within the duration. [`var repeatMode: AnimationRepeatMode`](/documentation/RealityKit/ActionAnimation/repeatMode) An option that determines how the animation repeats. [`var speed: Float`](/documentation/RealityKit/ActionAnimation/speed) A factor that changes the animation’s rate of playback. [`var trimDuration: TimeInterval?`](/documentation/RealityKit/ActionAnimation/trimDuration) An optional duration that overrides the calculated duration. [`var trimEnd: TimeInterval?`](/documentation/RealityKit/ActionAnimation/trimEnd) The optional time, in seconds, at which the animation stops. [`var trimStart: TimeInterval?`](/documentation/RealityKit/ActionAnimation/trimStart) The optional time, in seconds, at which the animation plays. ### Type Aliases [`typealias EventDefinitionType`](/documentation/RealityKit/ActionAnimation/EventDefinitionType) [`typealias EventParameterType`](/documentation/RealityKit/ActionAnimation/EventParameterType) ## Relationships ### Conforms To [`AnimationDefinition`](/documentation/RealityKit/AnimationDefinition) --- Copyright © 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)