# PhysicsMotionComponent A component that controls the motion of the body in physics simulations. ``` struct PhysicsMotionComponent ``` ## Overview You specify velocities in the coordinate space of the physics simulation defined by [`nearestSimulationEntity(for:)`](/documentation/RealityKit/PhysicsSimulationComponent/nearestSimulationEntity(for:)). The behavior of an entity with a physics motion component depends on the entity’s [`mode`](/documentation/RealityKit/PhysicsBodyComponent/mode) setting: - [`PhysicsBodyMode.static`](/documentation/RealityKit/PhysicsBodyMode/static): The physics simulation ignores the velocities. The entity doesn’t move. - [`PhysicsBodyMode.kinematic`](/documentation/RealityKit/PhysicsBodyMode/kinematic): The physics simulation moves the body according to the values you set for [`angularVelocity`](/documentation/RealityKit/PhysicsMotionComponent/angularVelocity) and [`linearVelocity`](/documentation/RealityKit/PhysicsMotionComponent/linearVelocity). - [`PhysicsBodyMode.dynamic`](/documentation/RealityKit/PhysicsBodyMode/dynamic): The physics simulation overwrites the velocity values based on simulation, and ignores any values that you write. ## Topics ### Creating the motion component [`init()`](/documentation/RealityKit/PhysicsMotionComponent/init()) Creates a physics motion component at rest. [`init(linearVelocity: SIMD3, angularVelocity: SIMD3)`](/documentation/RealityKit/PhysicsMotionComponent/init(linearVelocity:angularVelocity:)) Creates a physics motion component with the given velocities. ### Setting velocity [`var angularVelocity: SIMD3`](/documentation/RealityKit/PhysicsMotionComponent/angularVelocity) The angular velocity of the body around the center of mass. [`var linearVelocity: SIMD3`](/documentation/RealityKit/PhysicsMotionComponent/linearVelocity) The linear velocity of the body in the physics simulation. ## Relationships ### Conforms To [`Component`](/documentation/RealityKit/Component) [`Equatable`](/documentation/Swift/Equatable) --- 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)