# allowsResting A Boolean value that specifies whether SceneKit can automatically mark the physics body at rest. ``` var allowsResting: Bool { get set } ``` ## Discussion If (the default), SceneKit keeps track of whether the body is moving or affected by forces, automatically setting its [`isResting`](/documentation/SceneKit/SCNPhysicsBody/isResting) property to when it is “at rest.” The physics simulation runs faster when simulating fewer bodies, so treating a body as resting temporarily removes it from the simulation to improve performance. SceneKit automatically returns a resting body to the simulation if another body collides with it, if you change its position or velocity, or if you apply a force to it. However, SceneKit uses a faster, less accurate simulation when deciding whether to change a body’s [`isResting`](/documentation/SceneKit/SCNPhysicsBody/isResting) property back to . If testing your app reveals unexpected physics behaviors involving resting bodies, changing those bodies’ allowsResting property to may improve simulation accuracy. --- 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)