# ImpulseAction An action that applies an impulse to the physics body at its center of mass when played as an animation. ``` struct ImpulseAction ``` ## Overview This action requires a [`CollisionComponent`](/documentation/RealityKit/CollisionComponent) and [`PhysicsBodyComponent`](/documentation/RealityKit/PhysicsBodyComponent) with the [`mode`](/documentation/RealityKit/PhysicsBodyComponent/mode) set to [`PhysicsBodyMode.dynamic`](/documentation/RealityKit/PhysicsBodyMode/dynamic). Without these settings, the impulse has no effect on the entity. The example below creates an animation which applies an impulse to the entity after five seconds. ```swift // Create an action to apply an impulse, forcing the object to move upwards. let impulseAction = ImpulseAction(linearImpulse: [0, 1, 0]) // Create a small positive duration value. let duration: TimeInterval = 1 / 30.0 // Create an animation for the action, which will start playing // after five seconds. let impulseAnimation = try AnimationResource .makeActionAnimation(for: impulseAction, duration: duration, delay: 5.0) // Play the sequence animation that will play the actions. entity.playAnimation(impulseAnimation) ``` > Important: This action does not directly animate a bound property, such as ``doc://com.apple.RealityKit/documentation/RealityKit/BindTarget/transform``. > Tip: This action performs instantaneously, consider supplying a small positive duration value when creating the animation. ## Topics ### Initializers [`init(targetEntity: ActionEntityResolution, linearImpulse: SIMD3)`](/documentation/RealityKit/ImpulseAction/init(targetEntity:linearImpulse:)) Creates a new impulse action. ### Instance Properties [`var animatedValueType: (any AnimatableData.Type)?`](/documentation/RealityKit/ImpulseAction/animatedValueType) The type for the value that the action modifies over time. [`var linearImpulse: SIMD3`](/documentation/RealityKit/ImpulseAction/linearImpulse) An impulse in newton seconds (in physics simulation space). [`var targetEntity: ActionEntityResolution`](/documentation/RealityKit/ImpulseAction/targetEntity) The entity that the impulse acts upon. ## Relationships ### Conforms To [`EntityAction`](/documentation/RealityKit/EntityAction) [`Encodable`](/documentation/Swift/Encodable) [`Decodable`](/documentation/Swift/Decodable) --- 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)