Interoperability has no version number
At buildingSMART International, we’re often asked about our focus on different versions of the Industry Foundation Classes (IFC) standard. As the custodians of IFC, we’ve developed several versions over the years: IFC 2x3, IFC 4, IFC 4.3, and now, we’re working hard on the user requirements for new IFC functionalities in IFC 5.
Our guiding philosophy is simple: all versions of IFC are equally important. We support each version based on its relevance, adoption, and the needs of the industry. While IFC 5 represents the future of the standard, the majority of our resources are currently dedicated to supporting IFC 4.3, underscoring our commitment to the versions that are most actively used in the market. We are working hard on final details of IFC 4.3, supporting vendors with implementation, and defining the minimum level of implementation for Software Certification. We also still learn a lot from the usage of IFC 2x3 and IFC 4, which influences the new developments.
Why We Don’t Prioritize One Version Over Another
There is no one version of IFC that you ‘should’ use. Different industries, regions, and implementers adopt IFC versions at different rates, often influenced by their specific use cases, technical infrastructure, and maturity levels. For example:
- IFC 2x3: This version remains widely used and is deeply embedded in many projects globally. Its stability, maturity, and familiarity make it a go-to choice for certain workflows. As with any open standard, 2x3 will always remain available to the public.
- IFC 4 and IFC 4.3: These versions introduced significant enhancements, including better support for georeferencing, infrastructure, rail, and road projects. The ongoing work around IFC 4.3 is particularly focused on helping industries fully leverage its capabilities.
- IFC 5: This is an exciting step forward, designed to address new challenges and opportunities as the built environment becomes increasingly digitalized. However, it is not being developed to replace earlier versions but to coexist with them.
Resource Allocation: Supporting the Present While Building the Future
Our current budget reflects our priorities. While IFC 5 development is active, most of our funding and resources are focused on supporting IFC 4.3, ensuring that it meets the needs of users and delivers to its potential. This includes:
- Extensive support for implementers: Providing tools, documentation, and guidance to help software vendors and users adopt IFC 4.3 effectively.
- Certification programs: Ensuring interoperability and quality across the industry.
- Feedback loops with users: Listening to the market and addressing any challenges or improvements that arise.
This doesn’t mean we neglect IFC 5; rather, we ensure that its development aligns with the lessons learned from supporting earlier versions. At the same time, we respect the ongoing importance of IFC 2x3 and IFC 4, which are integral to many workflows worldwide.
All throughout history buildingSMART has been developing multiple versions in parallel. Just like any business is developing multiple updates of products in parallel. It is part of any business that wants to future-proof itself. This is why we are already defining the scope of IFC 5.1 as well. Just like we are thinking about a minor update of IFC 4.3 (to IFC 4.x), that would still maintain the interoperability with 4.3.
The Market Decides the Pace of Adoption
The whole reason buildingSMART exists is to give users the freedom to define their own workflows and take control of their digital destiny. Free choice is a core principle of openBIM so we will never force anyone to use a certain version of IFC.
At buildingSMART International, we don’t dictate which IFC version should dominate the market. Instead, we leave that decision to users, the industry, and the broader market. Our role is to provide a robust, reliable standard. The pace of adoption is driven by real-world needs.
Looking Ahead
As we continue to develop IFC 5, our focus remains on ensuring that all versions of IFC are well-supported and effective tools for users in the built environment. Whether you’re working with IFC 2x3, IFC 4, IFC 4.3, or preparing for IFC 5, our commitment is to deliver standards that meet your needs today and tomorrow.
We are blessed with a membership base and community that provides united support for this mission. We encourage the wider industry to explore, adopt, and innovate with the version of IFC that best suits their goals. At the end of the day, our mission is to empower the market with flexible, interoperable solutions.
Let’s build the future of interoperability, together.
Author: Léon van Berlo, Technical Director