Designing in an Active, Third Dimension with Building Information Modeling (BIM)
Andy Sorensen, AIA
Senior Associate | Architect
Building information modeling (BIM) refers to the strategy of intelligent 3D modeling to create interdisciplinary design solutions. Various software from a range of companies that fall under the BIM umbrella are available to the design world, with two of the most common being Revit by Autodesk, and Archicad by Graphisoft. The team of architects, engineers, interior designers and contractors, along with a growing number of building management personnel and ownership groups, can all access the information rich BIM file. It may vary greatly from project to project and firm to firm, but typically there is a separate 3D model for architecture, structural, mechanical/plumbing/electrical and civil engineering. The team can then collaborate in real time by all working simultaneously and syncing up their various models together. If the project requires it, cloud technology now enables this collaboration to occur from across the globe.
Conditions requiring greater discipline coordination effort are easily visualized with BIM as the various fields start to intersect. A duct running through a beam or a chase being too small for an internal roof drain pipe are just a couple examples of what can be realized as the disciplines are working concurrently. This ability to catch potential conflicts quicker, easier and prior to the start of construction is one of the major advantages of utilizing the BIM strategy compared to more traditional 2D drawing software. Quality control is now an active, day-to-day process rather than waiting for a milestone to check how well the disciplines are blending. The benefits can reach even greater realms when the model is shared with the contractors involved. Contractors can see quantities and types of materials modeled to help develop and tabulate bids or compare costs at an expedited pace. If familiar with the process, various trades may also engage the model to see the design strategies and explore alternatives as field conditions develop.
When designers are utilizing BIM, they no longer must draw a series of repetitious 2D lines to develop their drawings. When a wall is moved or changed in section, for example, it automatically updates the floor plans and schedules that are linked to it, reducing the chance for error and enhancing efficiency. Although much less than previous methods of building design, some 2D drafting on top of the model is still required to fill in the details. Additional capabilities the power of BIM can help unlock include virtual reality, energy modeling, lighting studies, structural testing, realistic renderings of exteriors or interiors and cost estimation scheduling.
One potential struggle the project team may face while utilizing BIM software is how much to model. Just because the team can model, produce and store more information, does not mean that doing so is always the best methodology. In a few clicks, one can create a building section, but is that section necessary and does it add to the clarity for constructing the building? Designers still need to maintain a level of criticality for what is needed to produce the best set of drawings for the project. When a designer models to a level higher than what is required for complete contract documents, it can result in billed time being wasted and a slow, oversized BIM model. A more minimal level of modeling may be adequate if the translation to the contractor is effectively portrayed in the final documents/specifications and the Owner will not utilize the BIM model moving forward for any advanced facility management.
The levels of BIM modeling detail have been defined from 100 (conceptual) to 500 (full as-builts). A typical construction documentation level will likely live in the range of 300 to 400. A full understanding of these detail levels is critical for the project leaders to properly convey the options and contract implications to the Owner. Not all BIM projects are created equal. The AIA has created a contract document template outlying the project expectations of BIM to help clarify responsibilities between Owner and Architect.
BIM is an exciting advancement to the design field, pushing the production method from a flat, static state to an active and collaborative third dimension. Design professionals are more unified with BIM and have a better understanding of the tactics of the disciplines outside of their own. Furthermore, BIM may have opened the door to an even more advanced, immersive design methodology. Manipulating and producing drawings within virtual reality is a very real possibility thanks to BIM. The future of building design production could see the project team ‘living’ virtually within the model, hopefully closing the gap between visualization and the built reality.