What Is Interoperability in BIM? BIM Interoperability Tools

Definition of interoperability

The basic definition of interoperability explains it as the ability of a given system or product to work with other products or systems. The ability to work together means that there are no access limitations or implementation restrictions of any kind. Most examples of interoperability rely on open standards as some sort of middle ground that different solutions can work with.

The definition of interoperability in the context of BIM is mostly the same, but there are some slight differences.

Interoperability in the context of BIM

BIM is a rather complex field as a whole, and the topic of interoperability in the context of BIM is far more specific than the basic definition. Interoperability (in the context of BIM) is the capability of different software solutions to exchange data via common exchange formats while also being capable of both reading and writing the same file formats (protocols).

A fairly common example of interoperability in the context of construction software is the capability to switch from one industry-specific product to another without losing data in the process. The primary purpose of this capability is to avoid lock-in, giving businesses more freedom when it comes to choosing different solutions for identical use cases.

The sheer complexity of every construction project (with multiple participants contributing in their own way to the project’s completion) makes it even more important for interoperability to exist in the context of BIM.

It is important to remember that BIM is still a relatively new industry with many proprietary standards and file formats, which significantly reduces the collaborative potential of such solutions. This situation is exactly why there is such a need for open standards in the industry.

Advantages of interoperability in BIM industry

Achieving interoperability in BIM can be challenging, and many of the possibilities depend entirely on the software provider’s ability to support standards such as IFC with no involvement from the client side. Nevertheless, properly configured interoperability within a BIM solution offers plenty of advantages to users:

• Better project management in the form of real-time data analysis and faster on-the-spot decision-making.
• Improved collaboration facilitated by seamless data exchange.
• More efficient cost management via easier detection of conflicts and more accessible resource planning.

There are many other specific advantages that can be attributed to the ability to share information between different BIM solutions with ease, but these examples are already a good showcase of how beneficial it can be when everything works correctly.

Interoperability vs compatibility

Communication between systems and applications can be boiled down to two primary elements: communication protocols and data formats. IMAP, TCP, HTTP, and FTP are the most common communication protocols, while the popular data formats include SQL, XML, ASCII, and similar.

Syntactic interoperability is achieved by systems and applications communicating and exchanging data via these standards and protocols. However, this kind of communication is insufficient for the successful transfer of BIM information from one software application to another, because the interpretation of the same information might differ across BIM solutions.

Semantic interoperability is what BIM solutions need. It is the ability to share information by referring to the same reference model in the form of a standard information exchange format (such as IFC).

However, an important distinction needs to be mentioned in the context of interoperability: the information exchange format used to create semantic interoperability cannot be the proprietary format of a solution that is already established in the market.

Many smaller vendors might see compatibility with a well-known solution’s file formats as a necessity for their own growth. Unfortunately, this turns interoperability into compatibility, a process of adapting to the existing market, which is almost totally dominated by existing software with no open standards in mind.

For example, Autodesk is a well-known software provider in the CAD-BIM market, and Revit might be the best-known BIM solution currently available. Multiple BIM solutions on the market offer some form of support for their competitors’ file formats to promote more accessible communication across the board, whether it is with plugins, extensions, or something that is built-in by default. If another solution adds compatibility with Revit’s proprietary file formats (such as RVT, RTE, RFA, and so on), it is an example of compatibility, not interoperability.

Interoperability and the situation in the industry

The topic of interoperability is widely accepted and talked about in the BIM industry, but not everyone is on the same page when it comes to choosing which standards are going to become the standard that all solutions should have to work with.

For example, Trimble and Autodesk’s joint statement indicates that both companies support IFC (Industry Foundation Classes) and COBie (Construction Operations Building Information Exchange) as the basis for interoperability in the industry in the future.

Alternatively, this interview of Greg Bentley of Bentley Systems is an alternative look at the same situation, claiming that it would be extremely difficult for IFC and COBie to be extensive enough and to go far enough to become a standard for data exchange that would satisfy everyone.

Interestingly enough, the same interview suggests that Bentley’s i-model  data format would be a better alternative for interoperability across the entire industry. The problem is that this is just another example of interoperability being confused with compatibility, since interoperability is not about using proprietary formats as the basis for communication between different solutions.

As such, it is easy to see how the topic of interoperability and data exchange between solutions on the BIM market has been widely discussed for some time now and will probably continue to be discussed in the near future.

Interoperability and BIM maturity levels

Building information management is a complex topic with multiple approaches to classification. It is also not a one-and-done solution, because different levels of BIM integration have differing advantages. One of the better-known classifications for different possible levels of BIM integration is the separation of all companies into at least three different “BIM maturity levels.” Differentiating between levels of adoption of BIM makes it possible to discern what might be considered sufficient for proper interoperability.

BIM level 1 represents the most basic level of integration with existing workflows, such as the generation of design documentation with no reusable data exchange and no interoperability in any way, shape, or form.

BIM level 2 is still not true interoperability, but it does allow for file-based collaboration and federated models. For example, BIM level 2 is a requirement for construction projects in the UK, including the mandatory combination of the native 3D models and COBie data to be used in construction projects. Unfortunately, native formats often make use of the software’s proprietary file types, which cannot be called interoperability.

BIM level 3 and beyond is where interoperability shines, shifting the collaborative accent from file-based collaboration to a centralized model that all parties can make use of and contribute to.

Most important phases in BIM interoperability

AEC industry professionals are among the most prominent examples of the audience for BIM, and all of these specialists need to have access to the same project model in order for the construction process to proceed smoothly. This model is later used throughout the project, including the on-site construction phase and beyond. As such, communication and access to information are essential.

Not only is interoperability a requirement in the project planning phase, but the same capability can also be an excellent advantage for multiple processes long after the construction process is complete.

The planning phase of any construction project is extremely important, and the proper involvement of AEC professionals is necessary. The problem is that the professions’ capabilities and software requirements differ significantly, but they all require access to the same project-related information.

In this context, there are only two options to choose from: using the same BIM solution for all tasks natively or using neutral file formats and standardized processes, which is known as “open BIM.” Native BIM is borderline impossible to implement due to the varying needs and requirements that each stakeholder might have. This leaves open BIM as the only option available, creating true interoperability as a result.

Interestingly, interoperability is not something that is useful only within a given project phase. It becomes even more helpful after a certain amount of time has passed after the construction project is finished. Most buildings have a need for renovation or remodeling with time, and this means that the AEC experts who are tasked with renovation will need access to the project’s design information from when it was built.

The problem with accessing regular BIM files after a while is relatively simple: compatibility. BIM solutions evolve and grow regularly, and some formats are expanded with no backward compatibility, while others are made obsolete completely. In this context, it is challenging to access the BIM files of a building if they are stored in a legacy format that is no longer supported.

This is not a problem for interoperable, open file formats such as IFC, which have entirely public source code and logic. This makes it much easier to interpret information using practically any BIM solution. In this context, extensive interoperability in BIM is a good idea for the future of the industry as a whole.

BIM interoperability as a two-way exchange process

There is a rather important factor that bears mentioning in the context of BIM interoperability, and that is the word “exchange.” One of the primary goals of interoperability is to have an easy way to “exchange” information, not just see it.

In simple terms, data sharing in the context of BIM should be a two-way street. All construction processes require the involvement of multiple parties – architects, engineers, and contractors – for them to be completed.

Even something as simple as a door involves dozens of people due to the number of different professions and skills involved in the process. The traditional way of doing these kinds of operations was to create drawings of the planned object and exchange them between different parties when necessary, which was always prone to multiple forms of miscommunication and risk.

Alternatively, using an application programming interface such as Representational State Transfer (REST) does not work for these kinds of situations, either. RESTful services can exchange information both ways when configured properly, but they are far too complex to be used for every single interaction between stakeholders. Integrating and maintaining such software would be a nightmare for any software developer.

In this context, it is easy to see why there is a need for a common language to begin with, and this is something that IFC, as a standard, has been striving for. It is used as the basis for many BIM data exchange methods, showcasing interoperability at its finest in the context of BIM.

IFC, IDM, and IFD

IFC has been mentioned multiple times in this article by now, and for a good reason. It is by far the biggest example of an open BIM standard, while also being a great showcase of BIM interoperability tools in the industry. IFC is a relatively simple concept: it is a specification for the building construction elements that are represented in a model and connected with one another. Both information about an object or idea and its connection with other elements in the same model are prime examples of the information that IFC stores.

At the same time, it would be fair to mention that IFC is far from the only technology contributing to the creation of industry interoperability. At least three more technologies have to be mentioned in the context of IFC: IDM, MVC, and IFD.

IDM means “Information Delivery Manuals”. It refers to the kind of information exchanged with IFC. IDM is the means of identifying which information is going to be communicated and what method is going to be used to communicate it.

MVD is “Model View Definition”. It is a supplementary methodology used to communicate how the information referred to by IDM is mapped within the borders of the IFC format.

IFD is another critical element of the process. It means “International Framework for Dictionaries” and used to add context to all the information shared by IFC so that it can be mapped and used correctly by different BIM solutions. IFC provides only relatively basic information about objects, but it is needed to provide semantic explanations of what each part of the object information means: material, dimensions, and so on.

While IFC is an important format that might become a true example of interoperability in the future of BIM, it still relies on many different technologies for the appropriate translation of its information. IDM, MVD, and IFD are the supreme examples of such technologies, and their further development is just as important as the ongoing effort to make IFC more mainstream in the BIM industry.

Interoperability in other industries

The very nature of the BIM industry makes the issue of interoperability quite different from how most industries exchange data across solutions and formats. In fact, BIM is something of an outlier and differs a lot from most industries when it comes to interoperability.

One of the biggest challenges for BIM in this regard is the age of the industry. The BIM field is relatively young, and it still has many proprietary formats (and a limited number of government regulations), with only a short list of common data formats such as IFC. The existence of so many data formats combined with the amount of information an average BIM model holds makes it very difficult to design open standards that can communicate information between different solutions without the loss of important details.

Another significant issue is the complexity of the information that has to be shared. An average BIM model includes a large amount of object information and detailed information about the dimensions of each object. This makes BIM data far more complex than the data used in most other industries that use interoperability in some way.

Take the healthcare industry as an example. The number of different types of data that need to be shared can differ and may include treatment history, patient records, insurance data, and so on,  but the information is not particularly complex in a physical sense. Most of it is still just text, images, and videos, while BIM works with complex three-dimensional models that even the most expensive hardware struggles to process.

As a result, it is clear that the situation in terms of data interoperability for BIM is somewhat unique, making it a very interesting topic to discuss.

Conclusion

BIM interoperability is an interesting topic that is closely tied to the much larger theme of open BIM formats such as IFC and COBie. It can be challenging to determine what interoperability actually means and what does not, in fact, constitute interoperability.

Open BIM standards have been discussed for a while now, and adding interoperability to the mix can make it even more difficult to understand. It is our hope that this article has showcased what BIM interoperability is and what it represents in the industry.

Frequently asked questions

Can interoperability affect BIM project time frames in any way?

The ability to share information between different stakeholders with no compatibility issues is a massive advantage for the entire project team. It lowers the potential amount of rework caused by miscommunication, improves collaborative efforts between stakeholders, and makes it several times easier to interact with project models once the construction process is complete (for renovation, disassembly, etc.).

How difficult is it to achieve interoperability with particular BIM software?

BIM interoperability can be a massive advantage for most companies, making it easier to communicate and share data with other solutions with no loss of data or context. Unfortunately, adding support for standards such as IFC or COBie is the only way to achieve interoperability, so it is usually up to the software developer to add interoperability support.

Is it challenging to work with interoperable BIM data formats?

While interoperability is a massive advantage by itself, it is still a good idea to check what kind of data can be transferred from proprietary BIM models to IFC models, since IFC itself is relatively basic regarding object descriptions and parameters. The standards themselves are constantly being revised and improved, as well, so it is possible that IFC will become even more helpful in the future.

Are there any examples or case studies that might showcase the advantages of interoperability in BIM?

The very nature of this question makes it difficult to pinpoint one or several examples of such a case, simply because practically every single BIM-centric construction project created using multiple BIM solutions can be considered a showcase of industry interoperability.

For example, the well-known Heathrow Airport Expansion in the UK has been used in many different situations as a showcase of BIM’s capabilities. It was also created with dozens of stakeholders using different software, and so communication between teams and software solutions would have been much more difficult without the existence of standards such as IFC. That makes the Heathrow Airport example a showcase of BIM interoperability and its advantages, including the ability to meet all deadlines, better coordination, smaller amount of rework, etc.

Alternatively, there is The Edge, a building in the Netherlands that holds the unofficial title of “the world’s greenest building.” The entire structure was designed and created using multiple BIM solutions that communicated with each other with no issues whatsoever. The ability to share information using open standards also made it easier to integrate various intelligent technologies into the building during the construction phase, such as temperature control, lighting control, and many others.