SwiftUI’s animation framework is built fundamentally around spring physics rather than traditional fixed duration timing curves. Apple recognized early on that direct touch manipulation requires momentum preservation to feel authentic to human muscle memory.
In SwiftUI, springs are characterized by two primary parameters: Response and Damping Ratio. The response parameter (measured in seconds) approximates the duration of a half-cycle of oscillation, determining how quickly the spring accelerates towards its destination.
The dampingRatio parameter defines how rapidly the energy dissipates. A damping ratio of 1.0 represents critical damping: the view reaches its target as fast as possible without any overshoot. A ratio below 1.0 introduces bouncy harmonic oscillation, while a ratio above 1.0 produces overdamped, sluggish movement.
In iOS 17+, Apple introduced the first-class Spring struct, allowing developers to configure bounce, blendDuration, and initial velocity with surgical precision. ExodeUI exports directly to this modern SwiftUI Spring format, ensuring your design system springs match Apple Human Interface Guidelines perfectly.