---
title: "init(dampingRatio:initialVelocity:)"
framework: uikit
role: symbol
role_heading: Initializer
path: "uikit/uispringtimingparameters/init(dampingratio:initialvelocity:)"
---

# init(dampingRatio:initialVelocity:)

Creates a timing parameters object with the specified damping ratio and initial velocity.

## Declaration

```swift
init(dampingRatio ratio: CGFloat, initialVelocity velocity: CGVector)
```

## Parameters

- `ratio`: The damping ratio to apply to the spring’s motion. To smoothly decelerate the animation without oscillation, specify a value of 1. Specify values closer to 0 to create less damping and more oscillation.
- `velocity`: The target property’s initial rate of change at the start of the spring animation. If the target property doesn’t change, specify a vector with dx and dy components of 0. For details about how to calculate this velocity, see doc://com.apple.uikit/documentation/UIKit/UISpringTimingParameters/initialVelocity.

## Return Value

Return Value An initialized spring timing parameters object or nil if the object could not be created.

## See Also

### Initializing a spring timing parameters object

- [init()](uikit/uispringtimingparameters/init().md)
- [init(dampingRatio:)](uikit/uispringtimingparameters/init(dampingratio:).md)
- [init(mass:stiffness:damping:initialVelocity:)](uikit/uispringtimingparameters/init(mass:stiffness:damping:initialvelocity:).md)
- [init(coder:)](uikit/uispringtimingparameters/init(coder:).md)