---
title: trimStart
framework: realitykit
role: symbol
role_heading: Instance Property
path: realitykit/fromtobyanimation/trimstart
---

# trimStart

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

## Declaration

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

## Discussion

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 you choose.

## See Also

### Timing the animation

- [speed](realitykit/fromtobyanimation/speed.md)
- [delay](realitykit/fromtobyanimation/delay.md)
- [duration](realitykit/fromtobyanimation/duration.md)
- [offset](realitykit/fromtobyanimation/offset.md)
- [timing](realitykit/fromtobyanimation/timing.md)
- [trimDuration](realitykit/fromtobyanimation/trimduration.md)
- [trimEnd](realitykit/fromtobyanimation/trimend.md)