2 June 2014
BIM: More Than Just an Extension of 3D CAD
In the AEC industry, the advent of building information modelling (BIM) concept was viewed by many as an evolution to better 2D and 3D computer-aided design (CAD) techniques. Very few saw it as an interdisciplinary, collaborative tool that would drastically change the design-build project workflow, the management structure of AEC firms, the teaming models, the delivery standards, and the role of key disciplines involved.
As opposed to the vertical communication channels and delivery methods required by the traditional design-build approaches which mainly employ CAD, BIM necessitates an open and integrated horizontal collaboration channel between all the key stakeholders of the project: facility owners, designers/architects, MEP (M&E) engineers, consultants and contractors. To realise the benefits of employing BIM as compared to 3D CAD modelling tools, firms need to significantly invest in knowledge/skills development, personnel training, management restructuring, and software tools. However, more than these tangible investments, AEC companies need a complete change in mind set in case they want to adopt BIM for their projects.
Whilst many professionals, especially those from small and medium-sized firms, see it as an extension of 3D CAD, BIM is anything but 3D CAD. It is a much larger concept which involves extensive pre-construction planning and multidisciplinary coordination to virtually model building facilities using smart parametric objects embedded with rich accurate information. This intelligent model then can be used by all stakeholders to extract respective views and relevant information thereby resulting in timely decision-making and project delivery.
Though BIM and 3D CAD are not mutually exclusive to each other, they have major differences as far as the approach and the output is concerned. In traditional 3D CAD, depending on the scope of project, architects prepare a set of construction drawings, including the plans, sections, and elevations. Since all these views are independent entities, any change in one view has to be manually updated in others. As a result, the process is not only time-consuming but also increases the scope for errors.
On the contrary, a building information model contains the architectural, structural and MEP system models of the proposed facility. It is prepared during the design and planning stage using details from all the key stakeholders including designers, engineers, MEP contractors, and subcontractors. Since a single database-driven model represents details required by all disciplines, any changes made by any of the team members are automatically updated across the model to plans, sections and elevations. Hence, all the project team members are updated on all the changes made by others thereby saving time, reducing cost resulting from duplication of efforts, and increasing the overall quality of construction drawing sets. Thus, making small changes to the architectural plan would result in those changes appearing simultaneously in the section, elevation or schedule.
Furthermore, the building blocks of 3D CAD models are lines, circles, arcs, and other graphical entities, which lack the flexibility of data analysis. These models only serve as geometric objects devoid of detailed parameters which are required by the entire AEC supply chain. In contrast, BIM models comprise building elements and intelligent systems, including columns, beams, and walls, which contain rich data related to parameters. If needed, additional parameters can be added to the pre-existing ones for more detail. And, this rich data can be effectively shared across disciplines for rich collaboration and on-time delivery.
Nevertheless, the success of any project which employs BIM depends mainly on factors which include the richness of information embedded in the 3D models, the degree of openness in the interdisciplinary data-sharing and collaboration standards, and the level of mutual trust among all the professionals involved. If prudently planned and implemented, a BIM model not only represents the essential building elements in detail; valuable information concerning spatial coordination, geographic location, quantity take-offs, material requirements, time schedule, and project cost can be extracted when needed.
In essence, a well-planned BIM model accurately represents the entire project design lifecycle. Though preparing for and implementing BIM strategies requires considerable investment of time, money, and effort, its benefits are multi-faceted and long-term.
As a result, if your firm operates in the AEC industry and is looking for an outsourcing vendor offering a cost-effective, high-quality BIM modelling and CAD drafting services, kindly contact us.