Connecting Design and Operation

BIM interoperability formats and classifications form the foundation of digital continuity in construction projects, ensuring structured data exchange and semantic consistency.

As presented in the previous article ISO 19650 and BIM Information Management, the structure of a BIM project relies on a rigorous organisation of roles and information flows. But this management can only be effective if the data exchanged between disciplines and tools retain consistent meaning and coherent structure.

BIM is built on two complementary foundations: exchange formats, which ensure the technical transmission of information from one software to another, and classifications, which give that information shared and lasting meaning. Together, they transform heterogeneous files into an interoperable, accessible and enduring knowledge base.

The idea of interoperability originated in the manufacturing and aerospace industries in the 1980s, where thousands of components and software systems had to be coordinated within the same digital process. Standardisation programmes such as STEP (Standard for the Exchange of Product Data) and PDES (Product Data Exchange Specification) enabled the transition from 2D drawings to full digital product models.

This philosophy inspired BIM: a building is no longer an assembly of drawings, but a system of interconnected information objects.

The IFC (Industry Foundation Classes) format, developed by buildingSMART International, is recognised as an international standard under ISO 16739. It constitutes the technical foundation of OpenBIM.

Based on an object-oriented data model, IFC describes each building element (wall, slab, equipment, space) through properties and relationships. It models not only geometry but also functional interactions.

Version IFC 4.3 extends interoperability to infrastructure and GIS integration. These developments reinforce the importance of BIM interoperability formats and classifications for long-term data accessibility.

COBie (Construction-Operations Building information exchange), launched by the US Army Corps of Engineers in 2007, addresses the information gap between construction and operations.

Rather than modelling geometry, COBie structures maintenance data into tables that can be imported into CMMS systems. It is derived from the IFC model through a Model View Definition (MVD).

COBie illustrates how BIM interoperability formats and classifications enable structured information transfer into facility management systems and support digital continuity.

The BCF (BIM Collaboration Format) separates issue management from the model itself. Each issue references IFC objects using a GUID, ensuring traceability across revisions.

This lightweight XML-based format has transformed coordination workflows by enabling structured communication without duplicating models.

The IDS (Information Delivery Specification), standardised by buildingSMART, formalises project information requirements in a machine-readable format (XML or JSON).

Validation software compares the IFC model against IDS requirements and produces objective compliance reports, linking contractual requirements to digital models.

OpenCDE (Common Data Environment) defines APIs that allow BIM platforms and document systems to exchange data in real time without intermediary files.

It extends BIM interoperability formats and classifications into live collaborative ecosystems.

The bSDD (buildingSMART Data Dictionary) ensures semantic consistency across systems. It connects classifications such as Uniclass and OmniClass through a shared digital dictionary.

This semantic layer is essential to BIM interoperability formats and classifications, guaranteeing that data retains meaning across software and territories.

If formats ensure structure, classifications ensure understanding. They allow elements to be identified, coded and interpreted consistently across the lifecycle of the asset.

Developed by CSI in the 1960s, MasterFormat organises specifications by trade divisions.

UniFormat II classifies building elements by functional systems and supports early cost estimation.

OmniClass introduced a multidimensional structure integrating products, spaces, activities and phases.

Uniclass 2015, developed by NBS, is a hierarchical and digitally native system widely adopted in Europe.

Standards such as ISO 12006-2 and ISO 81346 define common structuring principles. The bSDD aligns national and international systems, enabling global semantic interoperability.

Together, these standards define the ecosystem of BIM interoperability formats and classifications in modern construction.

• BIM interoperability is inspired by aerospace digital product modelling.
• Formats (IFC, COBie, BCF, IDS) structure information exchange.
• Classifications (Uniclass, OmniClass, UniFormat) ensure semantic coherence.
• Tools like bSDD and OpenCDE connect data dynamically.
• BIM interoperability formats and classifications guarantee digital continuity and long-term data value.

Updated: October 2025