# force(fromValue:toValue:position:velocity:) Calculates the force upon the spring given a current position, velocity, and divisor from the starting and end values for the spring to travel. ``` func force(fromValue: V, toValue: V, position: V, velocity: V) -> V where V : Animatable ``` ## Discussion This value is in units of the vector type per second squared. --- 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)