Sharing information with all members of a project team is one of the biggest obstacles contractors face in achieving success on complex projects — whether those obstacles involve adhering to budgets or finishing work on time. If you can figure out how to make communication happen, then you're well on your way to completing a profitable project that aligns with owner expectations.

The communication protocol employed as part of your BIM process can make a big difference in information-sharing. Are you using open BIM or closed BIM? 

What Is open BIM communication protocol?

Open BIM lets you manage collaborative workflows based on open standards; model data and information are easily traded between software systems. In open BIM, model data is exchanged via the IFC (Industry Foundation Classes) data model, and model-based communication is handled with the BCF (BIM Collaboration Format). It's agreed on by the majority of software vendors and ensures smooth data and information flow between different software systems within a project. 

This collaborative workflow also calls for a common data environment (known as a CDE, or a central repository, such as Bimplus by Allplan) to manage project data and share information with project team members.

Working in an open BIM environment allows you to choose your software solution — use whatever you like as long as it supports the required open standards. Effectively and efficiently work with your own software and generated models from other software solutions. 

Any contractor that meets all project qualifications can participate in an open BIM project, which allows for increased competition as compared to situations with restrictions such as: "Must use Software X to create the structural model." For this reason, public projects should always use open BIM to avoid the exclusion of certain contractors.

Because established solutions for clash detection or model analysis work with IFC files but not all possible native formats, open BIM also raises model quality. While there may be limits to using native data with the requirement of specific software, models based on open BIM standards can be used during the complete life cycle of a project — even during maintenance or renovation phases. 

What Is closed BIM communication protocol?

Closed BIM allows for collaboration within a defined software environment based on native data formats and distinct processes. 

In this environment, all project stakeholders must use the same software. This includes either dedicated software applications or systems that allow defined file formats to be imported and exported. 

Closed BIM may require you to license a specific software solution and train users, which can lower efficiency. It may also require you to divulge more information than you'd like about your construction process during the exchange of native data.

Making the right choice

How do you choose between open and closed BIM? As with most things, it depends on the situation and the scope of your project. In some cases, both approaches may even be used within a project.

If an architect and engineer work closely together during the initial design phase, using closed BIM can work (especially with the help of tools such as Allplan Share and Bimplus instead of data exchange via IFC). 

The resulting models can be published in an open BIM format to the CDE or any collaborative environment defined by the project's BIM manager. This allows models and connected information to be used by other project participants within their scope of work (such as the MEP planner, for example). 

As the project progresses, the MEP planner can include the architect and structural engineer within the open BIM workflow based on the BCF for issues managed via the main contractor's collaboration platform.

To sum it up: If contractors work closely together and use the same software within a project, then they can rely on closed BIM internally for their specific project scope even if the general project is an open BIM project. It's not an exclusive "either-or" choice.

Questions to ask yourself

Still trying to decide between open and closed BIM? Try asking yourself these questions to zero in on the best choice for your project:

• What outcome do you want for the process (besides project completion, of course)?

• Do you want a model you can hand over to the owner to help them operate the building or use as the basis for creating an IoT environment?

• Do you want to include specialized software products or specialists for different tasks that aren't part of your software environment?

• Do you want to base your collaboration on proven processes with open standards?

When deciding whether to use open or closed BIM for your next project, remember: There isn't a single answer that works in every situation. Take the project scope and team members into consideration while answering the questions above, and you'll uncover which approach can help you realize success.