What Is Open BIM?
Our customers often ask what Open BIM means and what other approaches to BIM implementation exist.
Many of our customers ask what Open BIM is and what other approaches to BIM implementation exist.
First, the transition to building information modeling is a process that unfolds in each country according to local needs, capabilities, and an understanding of its value. Almost from the beginning, however, BIM showed signs of becoming an international movement with its own patterns, advocates, leaders, marketing, and business interests.
This led to the creation of buildingSMART International, an international nonprofit organization bringing together specialists from around the world. Its members do more than simply want to implement BIM; they understand how it should be done. Recognizing the complexity of these processes encourages technological cooperation and brings together the knowledge and experience of millions of people.
The organization began in 1994 with what seemed to be a purely technical issue. At Autodesk's initiative, twelve U.S. companies formed an industry consortium to develop common recommendations for a set of C++ classes supporting integrated application development.
As the international construction industry increasingly adopted BIM, interoperability—the exchange of data between information models created in different applications—became even more important.
Initially, the organization was called the International Alliance for Interoperability (IAI, originally Industry Alliance for Interoperability and, from 1997, International Alliance for Interoperability). In 2005, it was renamed buildingSMART to emphasize its international role, a name that suggests “smart construction.”
Today, buildingSMART's main achievement is the development of IFC, an open data format that simplifies collaboration in construction and has become a neutral exchange format for BIM. Put simply, IFC is intended to provide a universal way to exchange information between models created in software from different vendors.
IFC is currently developed and maintained by buildingSMART International, a nonprofit organization that does not operate for profit.
In practice, buildingSMART International can be seen as an effective vehicle for introducing IFC internationally. To inform stakeholders and promote IFC, related standards, and technical developments, the alliance created the website www.buildingsmart-tech.org.
IFC therefore plays a major role in shaping both BIM technology and the software developed for building information modeling. As BIM has become fashionable in some circles, certain software vendors have started presenting their products as full BIM solutions simply because they can save data in IFC format.
This is where specific commercial interests begin to appear around buildingSMART's nonprofit activities.
The Open BIM concept emerged among buildingSMART members and took clearer shape around 2012. It promotes collaborative building design, construction, and operation based on open workflows and standards, primarily IFC.
Open BIM is also described here as a commercial marketing initiative by software developers such as Graphisoft, Nemetschek, and Tekla to promote their products in the global design and construction market, which those companies do not conceal.
Following mergers and acquisitions among software companies, the main promoters of Open BIM became Germany's Nemetschek Group and the U.S.-based Trimble Group.
To develop and maintain IFC and other modeling standards related to Open BIM, buildingSMART International established the Model Support Group (MSG) and Implementation Support Group (ISG). These groups play leading roles in standardization under Open BIM and certification of software that uses IFC.
For more information about the status and development of Open BIM, visit www.openbim.org.
Fig. 2. The construction of an airport in Abu Dhabi is an example of the Open BIM approach used by China's China State Constructions Engineering Corporation. The terminal roof structure was designed in Tekla Structures.
It is worth noting that not all software vendors support the Open BIM initiative, even though IFC import and export have effectively become standard requirements for BIM software.
Some major developers, especially Autodesk and Bentley, have nearly complete ranges of their own BIM applications. They primarily develop proprietary file formats and use internal integration platforms to exchange information between programs. Autodesk and Bentley also have a bilateral agreement to support each other's file formats, implemented in modern versions of their software.
Large organizations and even entire countries adopting information modeling do not always implement BIM through Open BIM. They often prefer a more flexible approach.
Why are there two approaches to BIM adoption and use? Setting aside the extensive messaging around Open BIM (which the author considers primarily a marketing concept), the main differences are these:
- Under Open BIM, information exchange between the main discipline-specific parts of a model takes place primarily through IFC;
- Under the broader approach (an informal name, as no official term has been declared), data is exchanged mainly through proprietary file formats, while IFC serves as a universal but secondary exchange tool.
- This seemingly minor conceptual difference can have substantial consequences for large organizations and even countries.
- Software vendors' choice of approach follows clear commercial logic:
- Open BIM is supported primarily by Nemetschek and Trimble. Nemetschek owns well-known products such as ArchiCAD, Allplan, and VectorWorks and recently acquired Solibri. Trimble's portfolio includes SketchUp, Tekla Structures, and point-cloud technologies. These products run on different platforms and need a way to work together; otherwise customers cannot build an integrated information modeling system. IFC provides that connection, giving rise to the “open and independent” Open BIM approach.
- The broader approach is dominant at Autodesk and Bentley, which already offer nearly complete BIM solutions based on their own software. They also grow through acquisitions, but integrate new products into their internal formats. Bentley applications share the Microstation platform. For these companies, IFC is therefore a supplementary format for sharing data with software outside their ecosystems. They do not reject IFC and recognize its value for interoperability, but do not base their development strategies on it.
Fig. 3. London's Crossrail rail line is an example of a large-scale project delivered mainly using Bentley Systems software.
Since all these companies compete, they naturally seek to expose rivals' weaknesses and are reluctant to support initiatives that benefit competitors more than themselves. That is why each approach has strong advocates and opponents, although the public discussion often remains friendly and professional.
What are the advantages and disadvantages of these two approaches for countries that have decided to introduce BIM into construction with government support?
- The standardized nature of Open BIM offers apparent independence from software vendors and their potential decisions. It may also lower costs for standardizing processes and deliverables—for example, requiring IFC compliance rather than creating a national BIM standard—and for maintaining libraries in IFC alone. However, independence from some vendors can become dependence on IFC itself and on its developers, including other software companies.
- The broader approach may appear more costly for a country to introduce, requiring common standards and libraries in multiple formats. Nevertheless, it remains more flexible and responsive to BIM development. IFC often follows innovations introduced in proprietary formats. If an entire construction sector relies on IFC alone, it may have to wait for the format to catch up before using the latest advances, while other countries move ahead. IFC developers may have different priorities, and innovative software vendors may have to fit new capabilities into an older exchange format.
Many countries choose their BIM development strategies primarily to support domestic software vendors—Finland is cited as an example—or major national construction companies. Other countries, especially those without large homegrown players, prioritize the ability to adopt new technology quickly.
In addition, many countries that lead in BIM seek to encourage economically connected but less advanced countries to adopt their own modeling methods, standards, and classification systems. This can advance both public and commercial interests, so BIM policy choices often involve politics.
Estonia, which followed the Finnish approach, is cited as one example. Another is the United Kingdom, which prioritizes global leadership, including in new technology.
At the level of individual firms and organizations, the same two approaches appear. Some want to make the most of software they have already purchased and learned. Others prefer to replace old systems and start BIM from scratch with a suite of tools from one vendor.
The choice depends on financial and political factors, as well as the knowledge and judgment of managers and change leaders. Sometimes those who initiate a BIM transition leave, and others must deal with the consequences of their decisions.
Fig. 4. A cafe project in Novosibirsk, completed entirely in Autodesk Revit by ARGO.
It may not appeal to everyone, but there is no single universal approach to implementing and using building information modeling worldwide, nor can there be. Instead, different perspectives and practical methods must be combined thoughtfully, with national and individual business interests taken into account.
Thus, while buildingSMART is a nonprofit alliance, its activities are surrounded by commercial interests from software vendors, groups of companies, and entire countries.
Our country is only beginning to introduce BIM in construction—or rather, trying to establish favorable conditions for its adoption. This means deciding which approach to follow now. Although the question is complex, it must be addressed first because the answer will shape national BIM standards, building-element libraries, and other resources needed for effective BIM use.
Kazakhstan does not yet have domestic BIM software vendors, and its construction companies show little ambition to expand into foreign markets. The broader approach described above therefore appears preferable for Kazakhstan at the national level because of its flexibility and long-term potential. It still recognizes information exchange through IFC, so it does not prevent individual businesses or organizations from adopting Open BIM.
As in medicine, the key principle is “do no harm”!