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# trimStart

The time, in seconds, at which the animation plays.

```
var trimStart: TimeInterval? { get set }
```

## Discussion

This property is `nil` by default, which plays the animation with `time`
= `0`. If you set a value, the animation edits the duration according to
the specified beginning time.

If you set a negative value for this property, the duration increases
and the additional animation data fills in based on the
[`fillMode`](/documentation/RealityKit/AnimationView/fillMode) you choose.

---

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