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# init(by:timing:isAdditive:)

Creates a new action to animate from
the deaultSource by a transform relative to the starting transform.

```
init(by: Value, timing: AnimationTimingFunction = .linear, isAdditive: Bool = false)
```

## Parameters

`by`

Transform which is used to increment the starting transform. Used to determine the final transform we animate towards.

`timing`

Controls the progress of the animation.

`isAdditive`

Specifies whether you can additively blend the output from the action’s animation.

## Discussion

`defaultSource` → `defaultSource + by`

---

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