Blog by the 3D Web Interoperability Domain Group of the Metaverse Standards Forum
Introduction
The charter and vision for the 3D Web Interoperability Working Group at the Metaverse Standards Forum is to leverage and extend current web standards to enable the metaverse, as was explained in more detail in our previous blog “Building The World Wide Webiverse.”
This new blog describes the work and the roadmap of the Working Group’s first project: linking and sharing virtual worlds.
Web of Worlds Core Principles
This project to link virtual worlds highlights a compelling analogy between the World Wide Web—a unified system of URL-addressable, interconnected interactive experiences—and what we envision as a cohesive metaverse platform. This platform would consist of numerous addressable and linked spatial experiences, or virtual worlds, collectively forming what we call the “Web of Worlds.” Just as websites create a networked digital ecosystem, these spatial-first experiences would interconnect to create a seamless virtual universe as shown in Figure 1.
Figure 1: The “‘Web of Worlds” model exposes metaverse worlds as web endpoints
We envision the “Web of Worlds” to be build on the current web infrastructure and support the following core requirements:
Unified Addressing System
A single URI pointing to each discrete virtual world and functioning as a link between worlds
Persistent data references in linked data environments
Capability to store URIs/URLs for later access
Simple URI sharing with additional users
Universal Experience Accessibility
The “Web of Worlds” should be accessible through any standard browser
Sharing of interactive spatial experiences rather than just isolated 3D data assets
Web app-controlled user experiences as the dominant delivery model, i.e., use of client data vs. remote rendering
Rich Spatial Experiences
Comprehensive user experiences for spatial data of any composition and size
Support for both static and dynamic spatial data composition
Capability to handle billions of addressable spatial data states
High visual efficiency and fidelity
Collaborative Environment
Seamless shared multi-user and multi-device scenarios
Support for mixed and dynamic user and device configurations e.g., desktop, mobile, and immersive devices
World-agnostic user identification and data authentication (e.g., SSO)
Linking to a virtual world as an endpoint can provide a unified API to expose standard concepts such as users, views, and spatial content. The endpoint API should include functions to join, view, and preview the world in a standard browser/user agent for a given user. Modern web app techniques, including adaptive and responsive frameworks that react to device and network requirements, can be applied to create widely accessible rich user experiences in the browser.
We can see examples of this pattern across the Web today in Single-Page Applications (SPAs) and Web Apps, such as Google Docs, where the user, state, and history are all identified on the URL. So, what information would be essential to represent on a metaverse experience endpoint? Our investigation into use cases will help us enumerate requirements.
Initial Requirements for Web of Worlds
We propose the following requirements for the Web of Worlds model:
Composition of world experiences from multiple assets and endpoints
Ability to jump to predefined viewpoints in worlds
Creation and sharing of new viewpoints
Provision of a preview of the experience before entering
Experience consistency, e.g., in view and navigation parameters, units, physics
Security, e.g., protection against Man in the Middle attacks
Opportunity: Building on Web API standards for Web of Worlds
To meet these requirements, we propose the following strategy:
Build on existing Web and HTTP/HTTPS stack and standards
Providing a single URL endpoint for each addressable world
E.g. “http://example.com/superverse/395844”
Enable opening the URL in a user agent to join the world as an interactive experience
Automatic user ID controlled join/rejoin management
Web-App controlled IO/data/pixel flow
e.g., Local data vs remote rendering
Existing users & views should be addressable
e.g., “superverse/395844/user/983”
Optionally open the URL in a user agent to preview the world
No additional user created, but user-based authorization needed
Web-App controlled IO/data/pixel flow
Existing users/views should be addressable
Optionally expose scene state as model data
Including external links, using multiple asset standards, e.g., X3D, USD, glTF
Extending Web Patterns and Possibilities
With today’s HTML, glTF, and X3D standards, we can already compose rich interactive online 3D experiences[1]. We expect to build and extend on these Web patterns:
Composing and modifying 3D scenes: live HTML editing of X3D + glTF:
Experience fragment API / Bookmarks example (X3D + glTF):
Preview and jump to views in worlds; create and share new views
Can be expanded to meet our “Metaverse Bookmarks” use case
Outlook and Roadmap
We invite Metaverse Standards Forum members to provide feedback and evaluations of this proposal. Forum members can provide use cases and requirements and evaluate and test this API specification as it undergoes prototyping towards potential standardization. Prototypes can be implemented with several engines in the ecosystem today, and one potential path for standardization is through the Web3D Consortium and ISO/IEC[2] (along with its SDO Liaisons at the World Wide Web Consortium (W3C), the Open Geospatial Consortium (OGC), and the Khronos Group), which can develop a specification for this functionality as a URL/URI API.
Join us!
The Forum is open for any organization to join – we welcome your participation in the Working Group to explore and evolve metaverse open standards for the 3D Web!
References
Integrating X3D and glTF Blog from the Web3D Consortium
ISO/IEC X3Dv4 supports glTF 2.0, WebAudio, and MIDI
