# AnimationStateProtocol The protocol representing the current animation state of an action animation. ``` protocol AnimationStateProtocol ``` ## Overview The animation state allows actions to animate a target value using RealityKit’s animation engine. Animating values with the animation engine allows for cross-fading and additive compositing with other RealityKit animations targeting the same value. Access the animation state structure from the event structure returned to `.updated` event handlers. Define a valid bind target and matching animation type to make the state structure available and non nil. > Note: Custom actions don’t support animating ``doc://com.apple.RealityKit/documentation/RealityKit/BlendShapeWeights``. ## Topics ### Associated Types [`associatedtype ValueType : AnimatableData`](/documentation/RealityKit/AnimationStateProtocol/ValueType) ### Instance Properties [`var defaultSource: Self.ValueType?`](/documentation/RealityKit/AnimationStateProtocol/defaultSource) The previous blend stage value. [`var defaultTarget: Self.ValueType?`](/documentation/RealityKit/AnimationStateProtocol/defaultTarget) The default unanimated value of the target. [`var deltaTime: TimeInterval`](/documentation/RealityKit/AnimationStateProtocol/deltaTime) The time that has elapsed since the most recent evaluation, or 0 if animation is paused. [`var evaluationTime: TimeInterval`](/documentation/RealityKit/AnimationStateProtocol/evaluationTime) The time at which the animation result should be evaluated. [`var normalizedTime: TimeInterval`](/documentation/RealityKit/AnimationStateProtocol/normalizedTime) The normalized time ranges from 0 to 1, and is the time at which the animation result should be evaluated. ### Instance Methods [`func storeAnimatedValue(ValueType) -> Bool`](/documentation/RealityKit/AnimationStateProtocol/storeAnimatedValue(_:)) Stores the action’s animated value, which the animation manager uses to produce a final animated result. Returns true on success, otherwise false. ## Relationships ### Conforming Types [`AnimationState`](/documentation/RealityKit/AnimationState) --- 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)