A persistent identifier for a resolved referent across systems and time. A candidate open standard for spatial identity.
4D-ID gives each resolved object, surface, agent, and environment, physical or virtual, one persistent identity that can survive movement, re-observation, vendor boundaries, and the boundary between real and virtual. It is an identity and continuity layer over the standards the world already uses (OGC GeoPose and DGGS, ISO 8601, OpenXR, glTF), not a new coordinate system.
Grounding determines which thing a record refers to; localization determines where it is. 4D-ID preserves the resolved referent across systems and time and records externally supplied state/evidence; it does not perform perception, grounding/matching or re-identification (including SEGS), localization, registration, or rendering.
The web gave every document a name that worked across every browser and server. 4D-ID does the same for the physical world.
Identities are shared and global, but what you can see and say about them is yours.
This is the specification: a candidate, versioned working-draft contract prepared for community review and possible future submission. Potential liaison targets include an OGC Standards Working Group and Khronos for the OpenXR and glTF bindings; this repository makes no adoption claim.
| Path | What it is |
|---|---|
parts/ |
The specification, in six parts. Part 1 (Core) stands alone. |
schemas/ |
JSON Schema 2020-12 for every record type. |
openapi/ |
OpenAPI 3.1 description of the access operations (Clause 10). |
conformance/ |
The conformance manifest: every test this candidate draft defines. |
CHANGELOG.md |
Notable changes per version. |
GOVERNANCE.md |
How this candidate draft is governed and possible future liaison paths. |
The reference implementation (a resolver you can run in an afternoon), the SDKs, and the conformance CLI live in sibling repositories:
reference-resolver— the resolver, Apache-2.0js-sdk— the TypeScript / JavaScript clientdemos— interactive browser demos, also live at 4d-id.org
Start with Part 1: Core. It is about thirteen pages and defines the whole model on four concepts: identity, hierarchy, pose, time. Every later part is optional.
| Part | Read it if you |
|---|---|
| 1 Core | implement anything; it stands alone |
| 2 Extensions and access | carry motion, history, attestation, or semantics; serve queries or agents |
| 3 Privacy and security | track people, resolve across zones, or serve static content |
| 4 Planetary-scale architecture | run more than one zone or authority, or operate identity lifecycle and externally supplied evidence/candidate matches |
| 5 Domains and presentation | connect simulation or generated environments to the real world |
| 6 Implementation guide | build one, and want to know which technique makes each rule cheap |
A requirement is in this candidate draft only if two independent implementations would fail to interoperate without it. About a hundred requirements survive that rule, each with a test. Everything else is guidance in Part 6.
External clients and demos—including an interactive resolver, an address-to-identity globe, and animated robot, drone, and ship examples—run at 4d-id.org. The resolver may resolve and record externally supplied candidates and authorized lifecycle decisions; it does not perceive, localize, match, register, or render.
Candidate Open Standard Working Draft 2.3. No standards body has adopted this draft. Offered for community review; see GOVERNANCE.md for possible future paths.
Review the draft and open an issue or a change request. See CONTRIBUTING.md. The specification evolves through documented, reviewable change.
The specification text is offered under an open documentation license for community review. The reference implementation, SDKs, schemas, and conformance suite are licensed Apache-2.0. See LICENSE.
The identifier format is permissionless to generate, but conforming resolution follows existing-identity-first: resolve an acceptable existing identity before minting; mint only when no acceptable match exists, subject to the lifecycle and authority rules. This candidate draft is designed for royalty-free publication and implementation.