---
title: "init(_:duration:spring:startVelocity:)"
framework: swiftui
role: symbol
role_heading: Initializer
path: "swiftui/springkeyframe/init(_:duration:spring:startvelocity:)"
---

# init(_:duration:spring:startVelocity:)

Creates a new keyframe using the given value and timestamp.

## Declaration

```swift
init(_ to: Value, duration: TimeInterval? = nil, spring: Spring = Spring(), startVelocity: Value? = nil)
```

## Parameters

- `to`: The value of the keyframe.
- `duration`: The duration of the segment defined by this keyframe, or nil to use the settling duration of the spring.
- `spring`: The spring that defines the shape of the segment befire this keyframe
- `startVelocity`: The velocity of the value at the start of the segment, or nil to automatically compute the velocity to maintain smooth motion.