# ForceEffectParameters The force effect input data to the effect’s update handler or closure. ``` struct ForceEffectParameters ``` ## Topics ### Instance Properties [`let angularVelocities: UnsafeForceEffectBuffer>?`](/documentation/RealityKit/ForceEffectParameters/angularVelocities) The angular velocities of all rigid bodies under the influence of the effect, or nil if angular velocity information was not requested. [`let distances: UnsafeForceEffectBuffer?`](/documentation/RealityKit/ForceEffectParameters/distances) The distance from the effect to each rigid body’s center of mass, or nil if distance information was not requested. [`let elapsedTime: TimeInterval`](/documentation/RealityKit/ForceEffectParameters/elapsedTime) The amount of time that has elapsed since the force effect was started. [`let entity: Entity`](/documentation/RealityKit/ForceEffectParameters/entity) The entity containing the force effect. [`let fixedDeltaTime: TimeInterval`](/documentation/RealityKit/ForceEffectParameters/fixedDeltaTime) The fixed delta time between simulation steps. [`let inertiaTensors: UnsafeForceEffectBuffer?`](/documentation/RealityKit/ForceEffectParameters/inertiaTensors) The inertia tensor based on the current rigid body’s orientation, or nil if inertia tensor information was not requested. [`let masses: UnsafeForceEffectBuffer?`](/documentation/RealityKit/ForceEffectParameters/masses) The mass of each rigid body, or nil if mass information was not requested or force mode does not require it. [`let orientations: UnsafeForceEffectBuffer?`](/documentation/RealityKit/ForceEffectParameters/orientations) The orientations of all rigid bodies under the influence of the effect, or nil if rotational information was not requested. [`let physicsBodyCount: Int`](/documentation/RealityKit/ForceEffectParameters/physicsBodyCount) The number of physics bodies to be updated. [`let positions: UnsafeForceEffectBuffer>?`](/documentation/RealityKit/ForceEffectParameters/positions) The positions of all rigid bodies under the influence of the effect, or nil if positional information was not requested. [`let velocities: UnsafeForceEffectBuffer>?`](/documentation/RealityKit/ForceEffectParameters/velocities) The velocities of all rigid bodies under the influence of the effect, or nil if velocity information was not requested. ### Instance Methods [`func setForce(SIMD3, index: Int)`](/documentation/RealityKit/ForceEffectParameters/setForce(_:index:)) Sets the force for each rigid body. [`func setTorque(SIMD3, index: Int)`](/documentation/RealityKit/ForceEffectParameters/setTorque(_:index:)) Sets the torque for each rigid body. --- 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)