# Creating 3D models as movable windows Display 3D content with a volumetric window that people can move. ## Overview This sample code project demonstrates how to create and display 3D models in a visionOS app, using volumetric windows that people can pick up and move around their environment. The app launches directly into a volumetric window containing a 3D model.  The window style in SwiftUI creates a 3D volumetric window that someone can pick up and move around their space, similar to a 2D window. ### Set up volumetric window requirements The `VolumetricWindow` view loads a USDZ file and displays its contents. The `defaultSize` value defines the dimensions of the initial volumetric window size. ```swift import SwiftUI import RealityKit /// A view that loads in a 3D model and sets the dimensions of the volumetric window to the same size as the model. struct VolumetricWindow: View { /// The default length of each side of the cubic volumetric window, in meters. static let defaultSize: CGFloat = 0.5 // ... } ``` The sample’s `EntryPoint` structure defines a volumetric window group and a `defaultSize` value that sets the initial dimensions of the view. The `Info.plist` specifies the as `UIWindowSceneSessionRoleVolumetricApplication` launching directly into the volumetric window. ```swift import SwiftUI @main struct EntryPoint: App { /// The multiplier for the height of the volumetric window. let heightModifier: CGFloat = 0.25 var body: some Scene { // Configure a window group with a volumetric window. WindowGroup() { VolumetricWindow() } .windowStyle(.volumetric) // Scale the size of the window group relative to the volumetric window's size. .defaultSize( width: VolumetricWindow.defaultSize, height: heightModifier * VolumetricWindow.defaultSize, depth: VolumetricWindow.defaultSize, in: .meters ) } } ``` SwiftUI requires three separate arguments to define the width, height, and depth of the volumetric window. ### Load a 3D model as an entity in a view The `VolumetricWindow` view loads a USDZ file as an instance and adds it to the scene. ```swift RealityView { content in // Attempt to load the entity that uses the filename as a source. guard let model = try? await ModelEntity(named: modelName) else { return } // Add the model to the `RealityView`. content.add(model) } ``` ### Adjust the entity to the size of the volumetric window The sample updates the scale and position of the entity in the update closure of to respond to volume resizing. The `viewBounds` object converts the coordinate space to a local-world coordinate space that `RealityView` uses. ```swift let viewBounds = content.convert( geometry.frame(in: .local), from: .local, to: .scene ) ``` The method computes a bounding box that contains the outer dimensions of the entity. The view bounding box places the model at the bottom of the y-axis value of the window’s view: ```swift // Set the model's position to the bottom of the visual bounding box. model.position.y -= model.visualBounds(relativeTo: nil).min.y // Adjust the model's position on the y-axis to align with the view bounds. model.position.y += viewBounds.min.y ``` The app sets the scale of the model to match the width of the view bounds. ```swift /// The base size of the model when the scale is 1. let baseExtents = model.visualBounds(relativeTo: nil).extents / model.scale /// The scale required for the model to fit the bounds of the volumetric window. let scale = Float(viewBounds.extents.x) / baseExtents.x // Apply the scale to the model to fill the full size of the window. model.scale = SIMD3(repeating: scale) ``` ## See Also #### Related samples [Creating SwiftUI windows in visionOS](/documentation/visionOS/creating-a-new-swiftui-window-in-visionos) Display and manage multiple SwiftUI windows in your visionOS app. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)