---
title: "Discover USDKit and what's new in OpenUSD"
description: "Learn how USDKit brings first-class Swift APIs for OpenUSD scenes, compression, accessibility metadata, Spatial Preview, and USD web delivery."
shoutout: "Unofficial, made with love by Superwall - the best way to monetize your apps."
category: "Graphics & Games"
---

# Discover USDKit and what's new in OpenUSD


[Watch on Apple Developer](https://developer.apple.com/videos/play/wwdc2026/285/)

Learn how USDKit brings first-class Swift APIs for OpenUSD scenes, compression, accessibility metadata, Spatial Preview, and USD web delivery.

## TL;DR

- USDKit is a new system framework for Swift apps that open, edit, compose, transform, and export USD stages with RealityKit and Spatial Preview integration.
- OpenUSD support on Apple platforms expands with updated OpenUSD, MaterialX, and OpenVDB, plus standards work for Particle Fields/Gaussian Splats and accessibility metadata.
- Preview on Mac adds 3D editing, asset conversion/compression, renderer selection across RealityKit, Storm, and a new Raytracer, with OpenPBR support.
- USD assets can be compressed through USDKit export options, Preview, or the usdcrush command-line tool using mesh compression and AVIF texture compression.

## OpenUSD foundation updates

USD remains the scene-description foundation for Apple spatial experiences. Apple highlights continued work with Pixar, the Academy Software Foundation, and the Alliance for OpenUSD to make USD a formal industry standard, including the first formal core USD specification and ongoing domain specifications for geometry, materials, and physics.

Apple platforms update OpenUSD, MaterialX, and OpenVDB together, positioning them as a composable foundation for 3D scenes, rich materials, and volumetric data.

- OpenUSD: industry-standard library for describing 3D scenes.
- MaterialX: material-description technology integrated with USD workflows.
- OpenVDB: newly called out for volumetric data in the USD platform stack.
- Particle Fields: a new USD primitive type for Gaussian Splats and related particle-based representations.

## USDKit for Swift apps

USDKit is a new system framework that brings first-class USD support to Swift apps. It is designed to feel familiar to developers who already know USD while using Swift patterns for developers who are new to 3D scene authoring.

The walkthrough frames the core USD model: a Layer is a data file, Composition combines layers, a Stage is the composed scene, and Prims are scene objects with Schemas, Attributes, and Metadata.

- Create an in-memory stage with `USDStage()`.
- Open a stage from disk with `USDStage.open(_:)`.
- Traverse `stage.descendants` to inspect prims.
- Define new prims by path and type, then add references to compose external assets without copying their data.
- Use transform operations to create the correct xform attributes and maintain transform order automatically.

### Open a USD stage

USDKit starts from `USDStage`, either newly created in memory or opened from an existing USD file.

```swift
import USDKit

// Create a new empty in-memory stage.
let stage = USDStage()

// Open a stage from a file on disk.
let url = URL(fileURLWithPath: "/ALab/entry.usda")
let openedStage = try USDStage.open(url)
```

### Reference an asset and move it

The example uses USD composition to reference an external asset, then adds a translate operation to place it in the scene.

```swift
for prim in stage.descendants {
    if prim.name == "scope" {
        // Found the oscilloscope.
    }
}

let scope = stage.definePrim(at: "/World/scope", type: "Xform")
try scope.references.add("/ALab/assets/scope.usda")

scope.addTransformOperation(type: .translate)
scope["xformOp:translate", as: USDValue.Vec3d.self] = [2.5, 0.0, -1.0]
```

## Preview, rendering, Spatial Preview, and web delivery

Preview on Mac adds essential 3D editing for USD assets: direct scene manipulation, property and lighting edits, hierarchy browsing, asset conversion, and compression. Preview and Quick Look on Mac can use RealityKit, Storm, or a new high-fidelity Raytracer; all three support OpenPBR materials.

Preview also integrates with the Spatial Preview framework on macOS 27, creating a live connection from Mac to Quick Look on Vision Pro. Edits made on Mac can appear live in spatial context, including SharePlay collaboration for group review.

Safari introduces the Model tag for embedding USD models in web pages. On macOS and iOS it provides interactive 3D in the browser; on visionOS the model can break out of the page into the user's space.

- Use RealityKit rendering for consistency across Apple platforms.
- Use Storm when existing production pipeline needs require it.
- Use the new Raytracer in Preview for higher-fidelity reflections, shadows, and lighting.
- Use Spatial Preview when a Mac app needs live review on Vision Pro.

## Accessibility metadata in USD

Apple has driven standardization of accessibility metadata directly in USD so 3D objects can carry assistive labels and descriptions. The metadata can be authored through USD APIs and has direct support in Blender and Maya.

In the USDKit walkthrough, schema-specific convenience APIs are not assumed. The example applies the multi-apply `AccessibilityAPI` schema, creates the required attributes by their specification-defined names, and sets a concise label plus a richer description.

- Apply `AccessibilityAPI` to the relevant prim.
- Create `accessibility:default:label` and `accessibility:default:description` attributes.
- Set values that help assistive technologies identify the object in context.

### Apply accessibility label and description

Accessibility metadata is authored as USD schema and attributes, making it portable across USD tools and APIs.

```text
try scope.applyAPISchema("AccessibilityAPI", instanceName: "default")

scope.makeAttribute(named: "accessibility:default:label", as: .string)
scope.makeAttribute(named: "accessibility:default:description", as: .string)

scope["accessibility:default:label", as: String.self] = "Oscilloscope"
scope["accessibility:default:description", as: String.self] = "Vintage signal analyzer with a 3D wireframe display, topped by a color bar test monitor"
```

## Compression and integration choices

USDKit can export compressed USDZ packages using export options for texture and mesh compression. The session cites a mesh compression codec developed with the Alliance for Open Media that can reduce mesh sizes by up to 90%, and AVIF texture compression; together, assets are described as seven times smaller on average.

The same compression workflow is available without writing code through Preview or the `usdcrush` command-line tool. Apple is working with Pixar to bring the compression support to OpenUSD.

For Apple-platform apps, USDKit is the recommended system-provided path. Advanced Swift or open-source workflows can use SwiftUSD through Swift Package Manager, and cross-platform C++ codebases can embed OpenUSD directly as a framework.

- USDKit: best starting point for Swift apps on Apple platforms.
- SwiftUSD: open-source Swift bindings for advanced or cross-platform Swift workflows.
- OpenUSD framework: C++ integration path for cross-platform codebases.
- The same USD file foundation is shared across these integration paths.

### Export a compressed USDZ package

`exportPackage` can request smaller texture files and smaller mesh files when producing a USDZ package.

```swift
let output = URL(fileURLWithPath: "/ALab/alab_compressed.usdz")

try stage.exportPackage(
    to: output,
    options: [
        .preferSmallTextureFiles(quality: .standard),
        .preferSmallMeshFiles
    ]
)
```

## Related Sessions

- [Discover the Spatial Preview framework](https://wwdc.ai/2026/282)

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