Glossary July 25, 2023
Updated 18 January 2024 by James Ocean
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Open BIM in AECO Industry

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BIM as a technology and a methodology earned quite a lot of attention in the past decade or two, offering a different approach to construction management that promises many different benefits with few shortcomings. The potential benefits of BIM are so significant that even the construction industry (widely considered to be one of the most, if not the most, conservative industries in the world) changed a lot of its processes in a BIM-friendly fashion.

There are three main ways to decipher the acronym that is “BIM”, and all three of these explanations are closely connected:

  • Building Information Model is what a lot of businesses often refer to as “digital prototype” – a 3D CAD model that also includes a lot of different data about the model as a whole and all of its parts specifically
  • Building Information Modeling is an ongoing process of using the aforementioned digital prototype, accessing existing project data and adding new information to be accessed by other project participants
  • Building Information Management is the process of controlling and organizing different processes using the aforementioned digital prototype as the main source of information

It is easy to see why BIM is considered so drastic in terms of how many changes it brings and how many processes it can affect – it is not only a completely different data-sharing model but also a different process of interacting with that data.

A BIM model can act as a single source of truth for all project participants; it can be used and modified throughout the project’s entire lifecycle, from the design phase to the construction phase and even including the post-construction phase. Some of the more sophisticated variations of BIM can even be helpful to building owners in tasks such as maintenance, repair jobs, or disassembly.

BIM brings many advantages to the board, including improved collaboration, reduced number of errors and reworks, improved design efficiency, better resource handling, and so on. However, as advantageous and beneficial as the BIM methodology may be, it has its issues. One of the biggest issues of widespread BIM adoption right now is the issue of data formats – which is how we transition to the topic of openBIM.

The definition of OpenBIM and closed BIM

The very basic definition of both open BIM and closed BIM comes from the nature of the BIM data in question – open BIM implies that the data is stored in commonly-shared formats and can be used in different software variations, while closed BIM uses proprietary formats that can only be opened in the same software (or the software from the same software provider).

Suppose we have to go for more formal definitions. Open BIM can be defined as a universal approach to project realization with a big focus on open standards and commonly acceptable data formats. Closed BIM, on the other hand, performs BIM tasks and operations using a proprietary data format, creating a necessity to use a BIM solution from a specific developer or software provider – which is why it can also be referred to as “lonely BIM”.

Open BIM in details

While both open BIM and closed BIM technically work towards the same set of goals that BIM has as a whole, there is a noticeable difference in how they approach the same task or issue. Closed BIM relies a lot on the same format removing or greatly reducing the potential miscommunication or design errors, while open BIM software uses commonly accepted standards and file formats to share data across different software variations.

There are still quite a few BIM solutions that use the closed BIM approach, even though open BIM is much more convenient as a whole, with every construction project being a highly complex network of different specialists and software types that have to communicate with one another in not just words, but also information in the form of models, datasheets, etc.

The advantages of open BIM compared with closed BIM

Open BIM elaborates upon the BIM as a methodology focused on collaboration and cooperation between departments, offering greater data transparency and easier communication without forcing people into using a specific BIM or CAD solution.

There are plenty of benefits that open BIM can provide to its users, including:

  • Flexibility in terms of software
  • Reliability of data as a whole, making it possible to be used across different solutions
  • Better interoperability via using open and neutral standards
  • Higher long-term sustainability with commonly accepted data formats
  • Better collaboration across departments as a whole

Open BIM as a standard has been pioneered by buildingSMART International, and it has been the home of all open BIM developments ever since.

BuildingSMART International and its connection to open BIM

BuildingSMART International (or bSI) is a global non-profit community widely accepted as the “home” of open BIM. The main goal of buildingSMART is to drive digital transformation in the construction industry using open and neutral standards such as data formats.

BuildingSMART consists of members, partners, and chapters, and three different Programmes act as the support network for specific activities that bSI performs, such as:

  • User Programme – for general open BIM promotion tasks, including organizing various summits and events, while also working on identifying future needs of the industry as a whole
  • Compliance Programme – for all certification-related tasks, be it about organizations, BIM personnel, specific software, or something else entirely
  • Standards Programme – for developing and updating various standards, technical documents, and reference websites

Speaking of open BIM standards, there are three categories we can split all of the open BIM standards into – data standards, services, and workflow standards.

Data Standards rely on two major points of interest – IFC and MVD. IFC stands for Industry Foundation Classes, a data cataloging standard for most BIM-related information. MVD, on the other hand, is Model View Definition, representing some sort of filter on an IFC file that defines what data parts will be exchanged during a communication process.

BuildingSMART’s Services are all about the bSDDBuildingSMART Data Dictionary, an online service that can map various technical information in a standardized order.

Workflow Standards are mainly including BCF and IDM. BCF stands for BIM Collaboration Format, a way to streamline communication and make exchanging information between industry professionals easier. IDM is Information Delivery Manual, a standardization instruction for the aforementioned BCF.

At this point, there are over 200 different software products on the BIM market are considered open BIM-compliant, and this list keeps growing at an impressive pace. Both IFC and BCF are a large part of that effort, and both of them are worth looking into.

Industry Foundation Classes (IFC)

IFC, as a standard, can include various information, from identity data and information about people to object parameters, relationships between objects, and even entire processes related to these objects. IFC is the main answer to open BIM to all of the proprietary data formats on the BIM market, and it is even ISO-certified, giving it even more credibility in the eyes of an average user.

The very nature of IFC as a format is considered much more future-proof than any closed BIM data format since it can still be viewed and modified even if the original software that created this model would not be available anymore.

IFC as a format was first created in 1996 (1.0), and there have been three more versions – 2×3, 4.0, and 4.3. IFC 2×3 is considered the most popular version of IFC to this day, a staple of what this entire standard stands for. IFC 4.0 was released in March 2013, and its variation, IFC 4.3, was released in 2022, adding support for Infrastructure and Rail-related data.

This kind of version spread may look somewhat overwhelming at first, but the reality is fairly simple – most companies still use IFC 2×3, and IFC itself is not only viewable by any supporting software. Not only can IFC files be viewed by such software, but they can also be modified – since IFC is not a user interface but a BIM data model first and foremost.

BIM Collaboration Format (BCF)

Of course, one BIM data format is not the end of open BIM’s efforts to improve collaboration and strengthen workflows. There are also efforts to improve general work coordination and data sharing outside of comprehensive BIM models – which is where BCF comes in.

BCF, by its nature, is an XML file/server setup file structured in a specific way and mostly used for issue tracking purposes. It offers a 3D view of every specific issue captured via PNG and IFC coordinates, providing contextualized information to people and departments needing said information.

There are two main software types that BCF can be useful to, such as:

  • The coordination software, which usually covers issue tracking and issue management concerns with the help of a flexible user interface
  • The authoring software, which can both generate and distribute model problem data in BCF format – a BIM solution may have either a native BCF support or an add-on to create such compatibility

BCF itself was a file-based transfer at first, but it managed to evolve into a server-based collaborative workflow (with the help of bcfAPI) that is now used by plenty of different companies and enterprises

Why open BIM may not be for every company out there

While open BIM as a standard offers plenty of advantages, some shortcomings may cause specific companies from investing in open BIM software. For example, some bigger companies may prefer the comfort and safety of proprietary data that industry giants like Autodesk provide.

This particular software provider company is also one of the few CAD/BIM market participants that can afford to use proprietary formats, both because of how popular some of their solutions are and because of how many different software types Autodesk themselves can offer (with interoperability guarantees between all of them).

There is also plenty of skepticism around the entire initiative, and around IFC specifically, mostly because of multiple different versions of the standard and the need for workarounds for specific tasks. Additionally, there is a legitimate concern of data loss when transferring an IFC file between two different BIM solutions – this can cause the information created natively (not converted) to disappear or become unreadable.

The wealth of different solutions supporting IFC and open BIM can also be treated as a detriment, to some degree, since not all software providers create their solutions with the latest IFC version in mind, which may create unnecessary confusion when figuring out and testing for specific IFC standards and supported features.


Open BIM as an initiative can be incredibly helpful in many cases, especially when communicating projects between stakeholders and departments. However, an open standard such as IFC or BCF is at its most efficient when the user is aware of the limitations of such a format. Only then can it reap the biggest benefits from adopting open BIM software and using IFC in BIM-related tasks.

About the author
James Ocean

BIM/VDC Specialist. James Ocean is Head of BIMspiration at Revizto and keeps everything moving onwards and upwards. From supporting and teaching our internal team as well as our clients, James shows us the ins-and-outs and how to best leverage Revizto to maximize workflows, cut costs, and get all types of projects through the finish line.

Technically Reviewed by Aleksandr Yeghiazaryan
Aleksandr Yeghiazaryan

Aleksandr Yeghiazaryan is the Product Marketing Manager at Revizto, a cloud-based collaboration software platform designed for Building Information Modeling (BIM) collaboration. Founded in 2008, Revizto’s software technologies have been utilized by various organizations, including the City of Barcelona and the Organizing Committee for the XXII Olympic Winter Games.

Alex began his marketing career in 2017 at PUBLIQ, where he was responsible for managing content marketing campaigns globally. In 2021, he joined Revizto as a Marketing Content Leader and was later promoted to the role of BIM/AEC Tech Evangelist. Since 2024, he has been overseeing all of Revizto’s web content, ensuring that it aligns with the latest trends in AEC, complies with local BIM regulations, and more. Notably, Alex is also Revizto Certified, underscoring his expertise in the platform.

Alex is an alumnus of Quantum College, where he earned a degree in Mathematics. He was the winner of the British English Olympics in 2014 and has played a significant role in organizing and participating in six European Youth Parliament events. Besides his professional achievements, Alex is a skilled pianist and occasionally holds concerts.

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What is openBIM? Open vs. Closed BIM Open BIM, in its basic form, implies the ability to share data between different software appliances, improving collaboration and eliminating issues caused by proprietary data formats and vendor lock-ins. This particular data standard can be highly beneficial for users that are aware of its limitations, but it is also not the solution to all BIM problems out there – and this article explains why it is still a viable, even if not ideal, option for information sharing. 2024-01-18
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