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# defaultSize(_:in:)

Sets a default size for a volumetric window.

```
nonisolated func defaultSize(_ size: Size3D, in unit: UnitLength) -> some Scene
```

## Parameters

`unit`

The unit of length the dimensions of the window are specified in.

## Return Value

A scene that uses a default size for new windows.

## Discussion

Use this modifier to indicate the default initial size for a new 3D
window created from a [`Scene`](/documentation/SwiftUI/Scene) using [`VolumetricWindowStyle`](/documentation/SwiftUI/VolumetricWindowStyle):

```
WindowGroup {
    ContentView()
}
.windowStyle(.volumetric)
.defaultSize(Size3D(width: 1, height: 1, depth: 0.5), in: .meters)
```

Each parameter is specified in the unit you provide. The size of a volumetric
scene is immutable after creation.

This modifier affects only windows that have the volumetric style in visionOS.

---

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