When discussing digital transformation and digital twins in the architecture and construction industry, one international nonprofit organization cannot be ignored: buildingSMART International (bSI).

It is widely known as the organization behind IFC (Industry Foundation Classes), but its true role goes far beyond managing a file format. buildingSMART is an international standards organization for information infrastructure that supports interoperability across the construction industry and helps establish data sovereignty independent of any single software vendor.

This article takes an in-depth look at why buildingSMART was created and how it grew, from its often messy early history to the visible and invisible tensions with major software vendors, its relationship with Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the country’s BIM/CIM policy, its expansion to the urban scale, the ongoing technical roadmap toward IFC5 and the Web API era, and the open-source ecosystem that developers should understand.

The History: From the Founding of IAI in 1994 to Global Standardization

The history of buildingSMART spans five major turning points, from the early 1990s, when 3D CAD began to spread seriously on personal computers, to today’s digital transformation, which now extends into infrastructure.

 1994 ── "IAI" founded by 12 companies including Autodesk (STEP/EXPRESS-based)
   │
 1997 ── "IFC 1.0" released as the first step toward building information models
   │       (object-oriented modeling)
   │
 2005 ── Renamed "buildingSMART International" (openBIM declaration)
   │
 2013 ── "IFC4" released and standardized internationally as ISO 16739
   │
 2024 ── Adoption of "IFC4.3" for civil engineering and infrastructure expands,
          and the transition toward "IFC5" begins

The Founding of IAI by 12 Organizations in 1994

In the early 1990s, proprietary data formats proliferated across CAD software products. When design firms, construction companies, equipment contractors, and other organizations exchanged data, geometric distortion and the loss of attribute information occurred frequently. In other words, the industry suffered from a serious lack of interoperability.

To address this problem, 12 major companies and organizations representing architecture, building services, and IT—including Autodesk, AT&T, HOK, and Carrier—came together in 1994 to establish the IAI (International Alliance for Interoperability). This organization was the predecessor of buildingSMART.

IAI adopted STEP (ISO 10303), which already had a strong track record as a data exchange standard in manufacturing industries such as aerospace and automotive, together with its data description language EXPRESS, as the technical foundation for developing IFC (Industry Foundation Classes), a common data model for building objects.

The Birth of a Common Building Format: IFC 1.0 in 1997

After three years of concentrated development following the launch of IAI, its first major result, IFC 1.0, was officially released in 1997.

Unlike DXF/DWG or IGES data, which had largely represented collections of lines and surfaces as 2D or 3D geometry, IFC 1.0 introduced an object-oriented model in which building elements carried architectural meaning, or semantics, and attributes—for example, walls (IfcWall), columns (IfcColumn), and doors (IfcDoor).

Following updates to IFC 1.5 in 1998 and IFC 2.0 in 1999, CAD vendors began adding IFC import and export functionality, taking an important step toward practical 3D data exchange between different CAD systems.

Renaming to buildingSMART and the openBIM Declaration in 2005

In 2005, the organization changed its name from IAI to the current buildingSMART International (bSI).

This was a major turning point. The organization moved beyond the narrow role of a “technical alliance connecting CAD data” and redefined its mission as an international standards body leading vendor-neutral, open information management standards across the entire building lifecycle—from planning and design through construction and maintenance—under the concept of openBIM.

Around this time, national chapters were established one after another across Europe, including the Nordic countries, the United Kingdom, and Germany. buildingSMART rapidly evolved from a private-sector technology group into a global organization supporting nationally driven BIM standardization.

IFC4 and International Standardization as ISO 16739 in 2013

In 2013, IFC4 (ISO 16739:2013) was released as the successor to the long-dominant IFC2x3 and was formally recognized as an international standard by the International Organization for Standardization (ISO).

IFC4 not only improved geometric representation accuracy, but also strengthened attribute structures needed for environmental performance, construction management, and facility management (FM), including structures such as IfcMaterialDefinition.

This ISO standardization provided a strong legal and policy foundation for requirements in public procurement specifications across Europe, including the UK government’s BIM Level 2 mandate for 2016, to deliver data using openBIM based on ISO 16739 (IFC).

IFC4.3 for Infrastructure and the Transition Toward IFC5 from 2024

In 2024, ISO approved IFC4.3 (ISO 16739-1:2024), integrating roads, railways, bridges, ports, waterways, and geotechnical data.

This removed the technical boundary between building BIM and civil engineering InfraBIM/CIM, opening the door to managing entire urban infrastructure systems through a single open data model.

Today, buildingSMART is moving toward a full redesign with IFC5, leaving behind the 30-year-old STEP-based approach—effectively a single large text file—and moving toward a next-generation standard designed to work naturally with Web and cloud technologies, JSON, USD, and APIs.

Why buildingSMART Exists: Five Core Solutions

buildingSMART is often misunderstood as simply “the organization that creates the IFC file format.” In reality, it provides a coordinated set of five elements that together enable the openBIM ecosystem.

IFC (Industry Foundation Classes / ISO 16739)

Overview: An international standard for an object-oriented data model that represents columns, walls, doors, building equipment, geometry, and spatial relationships in a hierarchical structure.
Key feature: In addition to traditional building use cases covered by IFC2x3 and IFC4, the latest IFC4.3 greatly expands coverage into civil infrastructure such as roads, railways, bridges, and ports.

bSDD (buildingSMART Data Dictionary)

Overview: A Web dictionary service and API that maps national standards, such as Japanese BIM specifications and European classification systems such as Uniclass or OmniClass, together with company-specific property definitions, into global semantics.
Key feature: Even when properties use different languages or proprietary naming rules, bSDD URIs can allow them to be identified and converted as data with the same meaning.

BCF (BIM Collaboration Format)

Overview: An open standard for exchanging only issue information—such as where a clash or defect occurs—without having to resend an entire BIM model that may be several gigabytes in size.
Key feature: It consists of XML/JSON-based messaging and a RESTful API (BCF API), enabling issue synchronization across different tools such as Solibri, Navisworks, Revit, and Archicad.

IDS (Information Delivery Specification)

Overview: A next-generation standard for defining information requirements such as EIR or AIR in a format that computers can interpret and validate automatically, using an XML-based structure.
Key feature: Learning from the complexity of the older mvdXML approach used for Model View Definitions, IDS uses a lighter and easier-to-understand structure. It can automatically check requirements such as whether a specific wall object includes fire-rating and model-number attributes.

OpenCDE API

Overview: A common REST API specification that allows CDEs (Common Data Environments) from different vendors to interoperate seamlessly for project documents and BIM data.
Key feature: It consists of components such as the Foundation API and Documents API and standardizes cloud-to-cloud file sharing and authentication using mechanisms such as OAuth 2.0.

The Complex Love-Hate Relationship with Major IT Vendors and the Future of BIM/CIM

To understand buildingSMART, it is essential to understand both its uneasy coexistence with proprietary vendors such as Autodesk, whose Revit product holds a dominant market position, and its relationship with Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the country’s BIM/CIM initiatives.

Autodesk was one of the founding members of IAI and continues to provide significant funding and technical resources as a top-tier strategic partner.

From a business perspective, however, maximizing revenue can be supported by keeping users within Autodesk’s own native formats such as .rvt and its cloud ecosystem, Autodesk Construction Cloud.

As a result, Autodesk has always faced a tension between the strategy of prioritizing usability inside its own tools and the responsibility of supporting open standards that enable interoperability with competitors’ tools.

Political Pressure from European Governments and openBIM Requirements

Meanwhile, European countries including the United Kingdom, the Nordic countries, and Germany, as well as the European Union, have expressed strong concern about nationally and municipally important infrastructure data becoming dependent on proprietary formats controlled by a single major US technology company.

For this reason, public procurement strategies have increasingly required data delivery through openBIM based on ISO 16739 (IFC). In this context, buildingSMART also plays a political role as a technical safeguard for European digital sovereignty.

Analysis and Outlook for Japan’s Unique Term “CIM”

In Japan, MLIT introduced CIM (Construction Information Modeling) in 2012 as part of digital transformation in civil engineering and later used the combined term BIM/CIM alongside BIM for buildings.

At the time, one of the primary technical reasons Japan needed the unique label “CIM” was that IFC versions then in use, such as IFC2x3 and IFC4, were primarily building-oriented and lacked a common data model for civil engineering structures. MLIT therefore had practical reasons to use “CIM” as a separate banner.

However, after IFC4.3 was standardized internationally as ISO 16739-1:2024, roads, railways, bridges, and geotechnical data could be represented in a single IFC model. Technically, the boundary separating building BIM from civil engineering CIM therefore became far less distinct.

The administrative terminology has not been immediately changed, but after MLIT completed the broad rollout of BIM/CIM application in directly managed projects in fiscal 2023, the completion of IFC4.3 provides a strong policy opportunity to gradually converge the uniquely Japanese term “CIM” toward internationally standardized BIM based on ISO 19650.

The Next-Generation Technology Roadmap: From IFC4.3 to IFC5 and the Web/API Shift

buildingSMART is now undertaking a major technical transition away from the STEP-based approach it has used since its founding and toward modern Web architectures.

IFC4.3: Full Expansion into Civil Engineering and Infrastructure

Internationally approved as an ISO standard in 2024, IFC4.3 represents a historic expansion of IFC from a building-centered standard into one covering infrastructure as a whole.

Supported domains
Roads, railways, bridges, ports and waterways, and geotechnical data.

Value
Initiatives such as MLIT’s i-Construction, PLATEAU, and smart-city programs can manage roads and civil infrastructure digital twins using a unified data model.

Structural Reform in the Modular Next-Generation IFC5

IFC5, which is currently under development, is positioned as a full redesign that moves away from the 30-year-old STEP technology and adopts modern data engineering concepts.

Multi-format support
Instead of relying only on a single text file such as .ifc, the architecture is moving toward native support for Web-friendly JSON, RDF/Linked Data for the Semantic Web, and formats such as USD (Universal Scene Description / AOUSD) and glTF, which have become important standards in computer graphics and entertainment.

Component-oriented design (ECS model)
Geometry, attribute metadata, and physical simulation or relationships are separated into layers.

This enables a non-destructive architecture in which only the required attributes can be updated or retrieved independently.

Until now, workflows often required downloading IFC files ranging from hundreds of megabytes to several gigabytes and loading them into BIM software.

The world envisioned by IFC5 and the Web/API shift is one in which applications can directly access a specific object GUID in a cloud database over HTTP through BIM REST APIs or GraphQL, using operations such as GET and PATCH.

Web browsers, smartphones, and IoT devices would then be able to query and update digital twin data in real time through lightweight Web messages without parsing massive 3D files.

Beyond Buildings: Expansion into Cities, Operations, and Government

buildingSMART’s activities extend well beyond CAD/BIM file exchange. It increasingly functions as a broad ecosystem design organization for the construction industry, covering integration with urban spatial data, AI-driven automated regulatory approval, building operations and facility management, and professional education.

Specialist Committees (“Rooms”) and Digital Building Permits

Within buildingSMART, specifications are developed through domain-specific expert committees called Rooms, including the Regulatory Room, Sustainability Room, Infrastructure Room, and Airport Room.

Regulatory Room — Digital Building Permits
This is one of the most internationally visible areas. Systems such as Singapore’s CORENET X demonstrate a future in which BIM data in IFC format can be submitted to a government system and algorithms can automatically check compliance with building regulations and fire-safety codes. buildingSMART is working on standardizing this concept as the Digital Building Permit.

Sustainability Room — ESG and Decarbonization
This area develops common data structures for linking embodied carbon and LCA (Life Cycle Assessment) data for building materials with IFC properties, enabling automatic calculation of a building’s total environmental impact.

GeoBIM: Integrating GIS and Urban Digital Twins

GeoBIM is the technical concept of seamlessly integrating large-scale geospatial data (GIS) with high-precision building and facility models (BIM).

Alliance with OGC (Open Geospatial Consortium)
buildingSMART works with OGC, the international standards organization for geospatial data, to define coordinate transformation methods such as IFCMapConversion for integrating city models such as CityGML, CityJSON, and 3D Tiles with facility models in IFC using accurate absolute coordinate systems.

Expansion into urban digital twins such as PLATEAU
In initiatives such as MLIT’s Project PLATEAU and smart-city programs, these standards support information platforms that can move seamlessly from the urban scale down into individual buildings, rooms, and equipment.

Expansion into Operations & Maintenance and COBie

More than 80% of a building’s lifecycle cost is said to occur after completion during the facility management and maintenance phase.

COBie (Construction Operations Building Information Exchange)
A standard data specification for transferring information such as equipment warranty periods, model numbers, and maintenance procedures from design and construction BIM into building management systems and FM software at project completion.

Integration with ISO 19650-3
Provides an operational framework for smoothly transferring data from the construction-stage PIM (Project Information Model) to the operational-stage AIM (Asset Information Model).

International Standards for People and Quality: PCERT and the buildingSMART Awards

buildingSMART also leads standardization and quality assurance for people and advanced case studies, not just technical specifications.

PCERT (Professional Certification Program): A global certification program that recognizes professionals who understand and can correctly apply openBIM concepts and ISO 19650 information management processes, rather than merely operating BIM software. It is delivered through national chapters.
buildingSMART Awards: A global competition held annually. Rather than simply rewarding attractive 3D models, it evaluates how effectively projects use openBIM standards to overcome organizational and software boundaries and enable vendor-neutral data interoperability. It is regarded as one of the industry’s highest honors.

Open-Source Tools and Technology Stacks Developers Should Know

buildingSMART’s openBIM movement is not simply about setting rules for the construction industry. It is also a process of opening previously closed CAD/BIM data so it can be handled freely with Web technologies such as REST APIs, JSON, WebGL, and WebGPU.

Engineers developing applications in the openBIM ecosystem should understand the following open-source libraries and architectural approaches.

Major Open-Source Ecosystem

IfcOpenShell
C++ / Python
One of the most established open-source C++ engines and Python wrappers for parsing, creating, and generating geometry from IFC files.

web-ifc (That Open Company)
C++ / WebAssembly
A WebAssembly library designed to parse IFC files at high speed in the browser and render them in 3D using tools such as Three.js.

xBIM Toolkit
C# / .NET
A powerful enterprise-oriented open-source framework for working with BIM data in Windows and C# environments.

IFC-LBD (Linked Building Data)
W3C / RDF
A technology for representing IFC data as graph structures using RDF/OWL and enabling semantic queries with tools such as SPARQL.

Principles for Future Software Architecture

Avoid excessive dependence on vendor-specific APIs
Applications built only around vendor-specific APIs such as the Revit API are directly exposed to risks from version changes and licensing-policy revisions. Designing the core logic around IFC/openBIM standards is a more sustainable approach.

Loosely couple “geometry (glTF/USD)” and “metadata (JSON/Graph)”
A Web-standard architecture that stores lightweight mesh data for 3D visualization, such as glTF/GLB, separately from business attributes and property data, such as JSON/bSDD, while linking them through GUIDs, is one of the most sustainable and powerful approaches for next-generation construction DX development.

Reclaiming Data Sovereignty in Construction and Opening the Ecosystem

The essence of openBIM, which buildingSMART has promoted for more than 30 years, goes far beyond improving file-format compatibility.

It is fundamentally about establishing data sovereignty by freeing construction data from proprietary vendor specifications and lock-in and making data about social infrastructure genuinely shareable.

What began as a difficult industry alliance evolved through intense political and commercial tensions with major IT vendors into European policy-driven standardization, ISO standards, and eventually IFC4.3, which now includes civil infrastructure.

The ongoing move toward IFC5 and Web APIs could bring an even larger paradigm shift by moving the traditionally heavy CAD/BIM world onto the same foundation as modern Web standards such as JSON, REST APIs, WebGL/WebGPU, and USD.

From building permits and urban digital twins to decarbonization and operations and maintenance, the open standards defined by buildingSMART are beginning to function as common protocols across the entire construction industry.

The players that can combine open standards with modern Web and data technologies—rather than remaining locked into the operation of a particular commercial software product or proprietary plugin development—are likely to create the most sustainable and decisive value in the construction DX market of the future.

Topic buildingSMART

The Full Story of buildingSMART, the Command Center of openBIM — From Its Origins and Relationship with Autodesk to the Future of IFC5