Khronos Releases Open-Source iOS App for Viewing glTF Files

“Khronos glTF Viewer” is live on the Apple App Store with source code immediately available on GitHub under the Apache 2.0 license; developer participation and feedback is welcome

glTF is the most portable and accessible asset format for bringing 3D content to diverse platforms, including the web. This open, royalty-free specification minimizes the runtime processing to unpack and process 3D assets, while also supporting sophisticated graphics functionality, rich textures, and diverse materials. Broad industry support for glTF includes adoption of glTF 2.0 as an ISO/IEC International Standard. Now, Khronos is pleased to announce an open-source native iOS app, “Khronos glTF Viewer,” that enables users to view and interact with glTF assets on iOS devices, including in AR. 

This app is distinct from the glTF Sample Viewer, the official browser-based reference viewer from Khronos. Rather, it is squarely focused on bringing glTF viewing capabilities to iOS devices, bridging a crucial gap for the “JPEG of 3D” and hastening a future where content creators can deploy glTF assets on any target platform.

iOS App: Khronos glTF Viewer

The Khronos Group commissioned Fourspace to develop the native “Khronos glTF Viewer” iOS app, which is immediately available on the App Store, and enables viewing and interaction with glTF models directly on iOS devices, including the iPhone and the iPad. The app can display 3D models against a digital or AR background. The user can zoom, spin, and orient the model, inspecting it from every angle.

The app is a “Designed for iPhone” application, which means it also works on Mac computers with Apple silicon.

The application source code is released under an Apache 2.0 license, and is built using well-established, publicly available APIs and platform frameworks, including Swift and SceneKit, plus open source components such as glTFKit2, DracoSwift, and libktx.

The app currently supports all base glTF 2.0 features, as well as Draco compression and clearcoat PBR extensions. The full list of the currently supported glTF extensions is on the Khronos glTF Viewer app page. Khronos will seek to add support for additional glTF capabilities in future updates.

“In a collaborative effort, the Khronos Group and Warren Moore from Fourspace have tackled a significant challenge for our users: the ability to quickly and easily view glTF files in AR on their iPhones. Traditionally, glTF assets required cumbersome conversions before being used on iOS. This new iPhone app revolutionizes this process. Users can now directly view their glTF files in AR – just by clicking on a glTF 3D model, pointing their camera, and placing their model in the real world. High quality materials and lighting are taken care of by glTF magic. I’m also delighted to see the app released as an open-source project on GitHub, inviting others to learn and contribute. This is a great body of work!” said Michael Beale, Autodesk Developer Advocate.

Using the Khronos glTF Viewer App

Launch the app from your iPhone or iPad screen.

Choose from several pre-loaded glTF sample models – like the “Outdoor Chairs.glb” model shown above – or open your own glTF or glb models from your iPhone’s built-in file browser. 

You can also easily download glb models from the web and launch them in the app:

Tapping a model will open a preview, showing highly detailed, realistic materials and even animations. 

Tap “Object” or “AR” to switch between these two views:

• Object Viewer displays objects against a digital background. Users can swipe to rotate, pinch to zoom, or use two fingers to pan.
• AR Viewer places your model into the camera’s view. Once the app detects a plane, you can pinch to zoom or pinch-rotate the object’s orientation. To place your model in a new location, hold down to activate dragging.

Tap the (i) “info” button to access the glTF file’s author, title, generator, license, and copyright details.

Developing Derivative glTF Apps for iOS

Full application source code has been released on GitHub under an Apache 2.0 license to inspire innovative, industry and community-driven “glTF on iOS” experiences. Developers are invited to use the source code to develop their own derivative projects and drive the proliferation of glTF 3D and AR viewers, bringing the superb performance and rich detail of glTF models to the iOS ecosystem.

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Offering Feedback on the Khronos glTF Viewer App Project

This open-source project is a significant step in proving the viability of seamless glTF experiences on iOS, but there is more work to be done. Community input is invited to improve and build on this strong foundation to create the best possible toolkit for developers targeting iOS devices.

Developers and content creators are encouraged to share their feedback on the project GitHub page. Help improve the portability and performance of standards-based 3D by reporting bugs, requesting additional features, and suggesting enhancements. With your input, glTF models can be made as accessible on iOS as on any other platform.

Join the glTF Community

This open-source project was commissioned by the Khronos 3D Formats Tooling Task Sub Group, which supports the development of glTF-related tools, libraries and learning resources that enable developers and artists to make the best use of the glTF file format. Other glTF tools include: 

• glTF-Sample-Assets
• glTF Sample Viewer
• glTF Asset Auditor
• glTF Validator
• Tutorials
• Video Tutorials

Khronos welcomes feedback from implementers, content creators, engine developers, and artists on the evolution of glTF, including the tooling needed to support its use. Join the glTF Slack channel, or engage on Stack Overflow, Khronos Discord and the Khronos Discussion Forum to ask questions and offer suggestions.

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