At WWDC 2018, Apple announced version 2 of its augmented reality (AR) framework for iOS, ARKit, supporting shared experiences, persistent tracking, 3D object detection, and a new file format aiming to enable AR objects interoperability across Apple apps.
ARKit 2 shared experiences allow multiple users to see and interact with the same AR scene using different devices at the same time, with each user seeing the common virtual environment from their own perspective. To help developers get started with shared experiences, Apple released a Swift multiplayer game, SwiftShot, which allows up to six players belonging to two opposed teams to share a game board placed on a physical surface. Players fire a virtual ball aiming to knock out of the way wooden blocks placed on the board and finally knock down the three slingshots of the other team. SwiftShot uses MultipeerConnectivity, a technology that Apple introduced in iOS 8 that has not seen broad adoption, to let the iOS devices of the players communicate locally without resorting to any external server.
Similarly to Apple, Google recently introduced shared AR worlds in its ARCore 1.2 AR framework for Android but decided to use Cloud Anchors to share AR scenes across devices. Although Apple took a different approach than Google, ARKit should be able to work with Cloud Anchors as well. According to Reuters, behind Apple’s decision to allow phone-to-phone sharing of AR data there could be privacy concerns. Apple declined to comment on this claim, though.
Persistent tracking is another new feature that makes it possible to sort of leave virtual objects where they are in the environment and get back to them at a later moment. This could also be the case for a different user gaining access to an AR environment previously created by someone else.
Additionally, ARKit 2 greatly improves 3D image detection and tracking, which makes it even possible to take accurate measurements of real objects such as picture frames, posters and signs and more.
Last but not least, ARKit 2 also includes a new open file format optimized for sharing in apps like Messages, Safari, Mail, Files and News. The format, that Apple co-developed with Pixar, is called Universal Scene Description (usdz) and is based on Pixar’s USD format.
Part of USD’s appeal is its ability to create a 3D scene by "composing" many modular data sources (files) together into successively larger and larger aggregations.
Pixar documentation makes clear that this approach makes USD not ideal for all scenarios, in particular due to the lack of a default mechanism to flatten multiple USD files into a single file. Usdz aims to improve that by allowing to embed files of other formats in the same usdz archive leveraging USD plugin architecture. This should make it possible to use usdz for streaming applications as well.
ARKit 2 will be part of iOS 12 and is currently available in iOS 12 developer beta 1, which can be installed over-the-air.