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.

As-Built Construction Assets: Key to Future Planning and Facilities Management

Preparing ‘as-built’ drawings and models is certainly one of the most crucial requirements of any design-build project. These final set of construction assets validates how the contractor built the structure including all the changes and modifications that were made in the process. The finalised drawings and models are passed on from the contractors to the building owners and property managers.

The set of as-built drawings and models, though underestimated and neglected, broadly serve a dual purpose. Firstly, the as-built drawings and models act as a guidebook to the AEC (architecture, engineering, and construction) firms that are contracted for renovation and refurbishment of an existing structure. So, the time, cost, and resources that would have been utilised during pre-renovation survey are saved. Secondly, they help owners and facilities managers to conveniently undertake maintenance and refurbishment activities besides helping them during emergency situations e.g. for rapid evacuation.

Whereas data-rich as-built 3D building information models have obvious benefits over 2D drawing sets, the decision to choose one over the other mainly involves factors, such as the scale of the project, owner’s preference, and the design-build teaming structure. The owners of relatively small building projects may prefer 2D as-built drawings of an existing building, prepared by a technician after collecting accurate data on site. On the contrary, large-scale design-build and renovation projects may require BIM-driven as-built 3D models.

Assuming that the project in question has not had a BIM model for the design process which is then updated during the as-built stage of the project, there are two typical ways of preparing as-built BIM models. Firstly, using the as-built drawings and other construction drawing sets as the starting point, 3D BIM models can be prepared using applications such as Autodesk Revit. The second method involves the Scan to BIM technique where   point cloud data of the structures. This point cloud data is then converted into an intelligent BIM model using tools such as Cloudworx and Scan to BIM applications such as Revit.

The as-built drawings and BIM models serve as a comprehensive reference tool for owners and property managers. They benefit from these as-built drawings and models in the following ways:-

·     The finalised as-built construction assets make future project planning, including renovations, extensions, and redevelopments, convenient and cost effective for the owners.

·     Since the as-built drawings and BIM models contain complete details related to dimensions, fabrication, erection, elevations, sizing, materials, location, and mechanical/electrical/plumbing utilities, the owners can use this data and conveniently manage facilities within budget.

·     The owners can use these as-built assets to resolve disputes regarding insurance claims. In case of a massive loss due to extreme disasters, the insurance company will require extensive documentation, including the as-built drawings and models to support your claims.

As the as-built drawings and models are prepared by combining the drawings/models of all the building services, the owners and property managers can schedule maintenance operations of the building’s MEP (M&E) systems in a timely manner.