What is a BIM Object?
A BIM Object is a machine-readable specification unit stored in W3C Design Token Community Group (DTCG) format JSON. Each object is anchored to an IFC 4.3 entity class and carries three layers of constraint data:
- Specification — the IFC entity anchor, applicable Uniclass 2015 code, bSDD URI, and property set definitions.
- Regulation — jurisdictional overlays (building code clauses, fire ratings, energy standards) registered against the element type.
- Climate Zone — performance requirements that vary by geographic zone (ASHRAE, NBC 2020).
Key Plans
Key Plans extend the BIM Object model to the spatial program layer. A Key Plan is the smallest leasable BIM Object: a bounded IfcSpace defined by real furniture placement (Steelcase, Midmark manufacturer SKUs), a three-zone cross-section (Zone 1 Habitat / Zone 2 Magazine / Zone 3 Corridor), net leasable area, and accessibility compliance.
Key Plans nest into Tiles (climate zone boundaries), which nest into Floor Plates (full building-floor programs). The tool-buildingwidth Rust engine computes remainder-free nesting in both directions.
Standards
- IFC 4.3 (ISO 16739-1:2024) — entity backbone
- Uniclass 2015 — classification floor
- IDS 1.0 — regulatory overlay constraint format
- bSDD (buildingSMART Data Dictionary) — URI authority
- DTCG — W3C Design Token Community Group token format