How Open BIM Facilitates Collaborative Design?

Due to its multifaceted benefits, building information modelling (BIM) is rapidly gaining traction in the AEC industry as the key pre-construction planning, construction management, and post-construction facilities management tool. Whilst many firms have transitioned to this ‘intelligent’ model-based process, the ‘real’ potential of BIM can only be achieved by open exchange of design and non-design project information amongst key project stakeholders: architects, structural engineers, MEP design consultants, MEP engineers, and other trade subcontractors.

A common challenge faced by mid-sized to large projects is that not all project participants use the same BIM application. This is where the concept of closed BIM and open BIM comes into play. The above two approaches are fundamentally different ways of looking at 3D BIM modelling.

Closed BIM, also known as ‘lonely BIM’, is a BIM environment wherein the same version of a BIM application is used by all key project stakeholders. This approach may also include different trades using the BIM-compatible applications from the same vendor. As a case in point, the lead architect uses Revit Architecture to model architectural elements. The structural engineer uses Revit Structure to take the architectural BIM model as the reference and define the building’s structure whilst the MEP design consultant uses Revit MEP to model building services. Although no file conversion is required in the closed BIM approach, the process is restrictive in the sense that it only allows project participants well-versed with certain BIM tools to collaborate, thereby not allowing ‘true’ integration.

On the other hand, open BIM is a workflow wherein all participants can collaborate and exchange project information with each other using non-proprietary, neutral file formats irrespective of the BIM tools and applications they use. The information exchanged is not only limited to the BIM model’s geometric data but also includes other parametric data, such as specifications, quantity take-offs, material procurement, cost estimation, and construction phasing. Most common open BIM protocols currently in use include Industry Foundation Classes (IFC) and Construction Operations Building Information Exchange (COBie).

Whilst IFC allows exchange of both geometric and non-design data amongst different applications that support open BIM, COBie only allows facilities management data to be exchanged. Using IFC, the architectural BIM model created by the lead architect’s design team in Graphisoft ArchiCAD can be opened and manipulated by the structural engineer when his/her team works in Tekla Structures. Similarly, the integrated architectural and structural BIM model can be imported into Revit MEP platform by the lead MEP consultant. Once the detailed MEP design is complete, the federated model can be taken into a clash detection and 3D BIM coordination tool, such as Navisworks again using IFC format. This leads to workflow-level collaboration amongst key project members which is the essence of BIM compared to the conventional 2D CAD workflows.

At XS CAD, we have an extensive know-how of both open BIM and closed BIM methodologies due to the fact that we have provided 3D BIM modelling and 3D BIM coordination support to architects, MEP engineers, and contractors in the US, the UK, Canada, Australia, and India. To find out more about how your project can benefit from our BIM modelling services, contact us.


Issues Affecting The Adoption of 3D BIM Modelling

Issues including cost and time overruns, material wastage, and process inefficiency have marred the architecture, engineering, and construction (AEC) industry worldwide. Whilst the reasons behind this may differ from project to project, lack of interdisciplinary coordination amongst the designers, the building services engineers, and the contractors is the most common of all. Considering these unfavourable project outcomes, there is a significant push from the governments, mainly in developed nations, to accelerate or mandate the adoption of 3D BIM modelling in varying levels for government-funded projects.

Whilst parametric modeling tools such as BIM technology is being increasingly used for government projects private construction projects are also seeing the benefits with many employing forward-looking AEC firms that have already transitioned to using information-embedded Revit 3D models for design as well as construction stages. Although moving from traditional CAD-based design processes to modern BIM-enabled workflows is essential to eliminate design/coordination clashes and maximise project efficiency, there are some key inhibitions and apprehensions to what is a paradigm shift for the industry.

Firstly, many AEC firms have long been using the traditional 2D as well as non-BIM 3D CAD workflow for pre-construction 3D planning and are highly resistant to change their current conventional processes. More often than not, such firms are completely apprehensive of embracing new technology or are slow adopters of new technology and decide to change only if requested by clients or if they are part of a framework agreement requiring adoption of such technology.

Another factor that pushes potential BIM implementers back is the steep learning curve of its tools and their real-life applications specific to disciplines, such as architecture, MEP engineering, and structural engineering. One common concern is training CAD technicians, who are familiar with drafting tools such as AutoCAD, and BIM and clash detection applications, such as Autodesk Revit and Navisworks.

The biggest impeding factor to BIM implementation is the perception amongst certain groups that current projects during the BIM transition period, will suffer. As BIM adoption is much more than just software training, it requires an overall change in the way a building project is conceptualised, designed, constructed, and maintained. Whilst the traditional design methods required CAD managers with a team of CAD technicians, the modern BIM-based projects require BIM managers who liaise with discipline-specific representatives to map out the level of details (LOD) or BIM Phases required by the client, worksharing protocols/processes, and assess the adherence to interoperability and information-exchange standards.

Furthermore, there is a widespread opinion amongst the AEC fraternity that whilst adopting a full-fledged 3D BIM modelling for the entire lifecycle of a building drives cost, time, and energy performance efficiencies, tremendous effort goes into preparing custom detailed content to client’s specifications. This group believes that whilst the generic libraries can be used for design and clash detection, accurately detailed models are needed to optimally use BIM for aspects, such as cost estimation, time scheduling, and quantity take-offs.

The requirement for BIM adoption also requires a level of interaction along the design and contracting teams that is not usual and has certainly been accelerated with the use of BIM practices. Clearly defining BIM scope and requirements between the parties involved is already becoming a challenge, especially for the MEP sector where designers and trade contractors have traditionally handled conceptual design and detailed design individually. The overlap in conceptual design and detailed design is becoming the type of challenge that MEP trades and MEP designers are getting used to resolving as part of BIM adoption.

Collectively these issues pose a challenge and sometimes cause the apprehension involved for BIM project take up, something that we observe will change with continued demand for intelligent building design.