The real value of building information modelling (BIM) as a process is in sharing and managing multidisciplinary information (design-related and otherwise) coming in from and going to several AEC supply chain partners, including the chief architect, the structural engineer, the MEP (M&E) design consultant, the MEP (M&E) contractor, the fabrication team and the installation team. Unfortunately, the perception still exists that for BIM to be successful all key project participants need to adopt the same BIM tool or application.

Whilst delivering a BIM project using such a design environment is possible, it is extremely rare in the real world to find a design team who uses the same 3D BIM modeling application as the structural team. The same can be said about the MEP services team, the fabricators and the installation team. On the other hand, the single-tool approach would make the process vendor-dependent and limit the interoperability between disciplines.

Keeping this in mind, it is important to discuss how open BIM facilitates project stakeholders using different BIM software applications to share and exchange data and achieve collaboration. At the heart of the open BIM design environment are neutral non-proprietary file formats that enable this exchange between different BIM tools, systems, cost estimation programs and other construction-related applications. In the context of BIM modelling, when we say ‘data’ we are talking about geometry-related 3D model information, cost estimation data, time schedule, quantity take-offs, procurement data and specification information, amongst others.

If GRAPHISOFT ArchiCAD is the preferred BIM tool used by the chief architect; Autodesk Revit MEP for the MEP services consultant; and STAAD Pro is the primary application for the structural designer. In the absence of open file formats, the BIM coordinator in charge would find it difficult to create a federated model (master BIM model) and carry out any clash detection activity. Alternatively, open file formats facilitate 3D BIM coordination and interoperability. It is mainly due to this reason that open BIM is deemed as ‘the’ way forward in pushing the adoption of holistic BIM processes.

The IFC (Industry Foundation Classes) file format is one such neutral non-proprietary file format developed by BuildingSmart, a group of organisations within the building and construction domain dedicated to improving processes within the industry through defining tools, processes and standards. IFC defines geometry and other construction-related data in a plain text-based binary structure which, in turn, is decoded by individual BIM software applications that support open BIM data exchange. This serves the purpose of all the stakeholders (architects, engineers, contractors, fabrication experts and installers) who use different BIM, cost estimation and clash detection tools to collaborate with each other.

Whilst finer nuances for different applications differ, BIM practitioners can save their native BIM files in an IFC format and their project co-partners can then import the same IFC files in their own native BIM application whilst retaining the geometric, parametric and construction-related information in the exchange. For example, after the design development and during the pre-construction phase, the federated BIM model can be imported as an IFC file into the application used by the specialist fabricator to enable modular off-site fabrication.

COBie (Construction Operations Building Information Exchange) is another important data exchange standard considering the use of building information modelling (BIM) for facilities and building operations management post project completion. This format enables only non-geometry project data which is updated throughout the construction phase to be handed over to the facilities management team. This information is otherwise contained in several disjointed documents and files making it extremely difficult to access, edit and update the data during operations management. The COBie format is essentially a spread sheet consisting of data, including equipment lists, manufacturer data, specifications, bill of materials and bill of quantities, amongst others. This neutral format can be accessed using different BIM, construction, design, estimation and maintenance software applications thereby helping facility managers to update and maintain this database throughout the building’s lifecycle.

As a result, familiarising with open BIM standards would help AEC stakeholders keen on adopting the BIM process derive true value in terms of cost efficiency, interoperability, on-time completion and on-site productivity.