1 Scope§
AGREED
1.1 Purpose§
This document specifies a vendor-neutral information model for the operational understanding of a building, a portable model for the graphics through which that building is operated, and a package format for moving both between systems without loss of meaning.
Its object is not interoperability at run time. Systems that exchange live values already have protocols for that. Its object is continuity: the ability of a building owner to take the accumulated understanding of a building out of one system and stand it up in another, years or decades later, without the cooperation of the system it came from.
1.2 What this version specifies§
- An encoding-neutral information model for building identity, spatial structure, systems and assets, points, typed relationships, operational intent, alarms, events, and provenance (clauses 6 to 14).
- A portable presentation model: drawings, coordinate systems and georeferencing, layers, elements with symbol roles or embedded figures, and bindings including command actions (clause 13).
- A requirement that every property carry a definition declaring its datatype, unit, and meaning (7.8).
- A governed extension mechanism, including the rules that keep an extension from being silently discarded (clause 15).
- An exchange package: container, manifest, integrity, an actuation declaration, and a mandatory completeness declaration (clause 16).
- A JSON binding with schema documents and a canonical form (clause 17), and conformance profiles and round-trip test methodology (clause 2, Annex A).
1.3 What is deferred§
| Domain | In v0.2 | Deferred to |
|---|---|---|
| Time-series history | Points declare whether durable history exists, its extent, and its nominal interval (8.8). Events, which are not time series, are core (clause 12). | BUS-2, time series |
| Structured knowledge | bus:KnowledgeNote carries free text with a kind, an author, a review state, and typed attachment predicates (8.9). | BUS-2, structured knowledge types |
| Vector figure format | Elements may carry a figure payload. The neutral vector format bus-vector-1 is named but not specified. | BUS-2, figure format |
| Analytic results | The attachment interface is normative (clause 15). The internal shape of an insight, diagnosis, or forecast is not. | BUS-4, analytic results |
NOTE The figure format is the one place v0.2 knowingly names something it does not define. An element in figure mode is portable in principle and not yet portable in practice. Where a symbol role exists, use it.
1.4 What is out of scope§
- Field and transport protocols — BUS-1 records how a point is reached (8.6). It does not define how to reach it.
- Proprietary method — How a vendor arrives at a conclusion is not specified and not disclosed. Only the durable result is portable.
- Rendering and interaction — No requirement constrains artwork, color, animation, transitions, typography, responsive layout, navigation design, or interaction model. Clause 13 is explicit about where this line falls.
- Three-dimensional geometry — Presentation is two-dimensional. A 3D or BIM model is referenced as a resource. IFC already exists and is better at this.
- Equipment taxonomy — A small structural class set, with external classifications preserved verbatim (7.7). Not intended to compete with the ontologies that define taxonomies.