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# init(dampingRatio:initialVelocity:)

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

```
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 [`initialVelocity`](/documentation/UIKit/UISpringTimingParameters/initialVelocity)    .

## Return Value

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

## Discussion

---

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