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

# trimStart

The optional 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.