How do you approach a sea change in the way architecture is drawn and documented? Most likely by testing the waters to get a sense of what may lie ahead. That was certainly the recommendation made by the technology committee at Ayers Saint Gross when it met several years ago to consider building information modeling or BIM.
“It was on the horizon and we were intrigued by its possibilities,” recalls the firm’s vice president Glenn Birx. “We thought we would dip our toe into it, and then assess it over the next year. It turned out this little toe in the pool created a tidal wave in the office.”
Ayers Saint Gross started to explore BIM in early 2004 when a technology-savvy architect in the firm’s Baltimore office was assigned to develop a small institutional project using Autodesk® Revit® building software. Before the completion of that project’s design, others on the staff were clamoring to try the program. It didn’t take much longer for the firm to make the decision that all new projects would be completed in Revit®.
The appeal of BIM lies in its ability to define objects in relation to other objects, so that if one object changes, the others will too. This parametric or bi-directional relationship allows an architect to make a change to a design in one view – a plan or an elevation, for example – and have that change be reflected automatically in all other views.
More significantly, BIM links a building’s three-dimensional geometry to all of its qualitative attributes — from materials and assemblies to quantities and costs. Any change made to a design instantly updates these various attributes. The result is a comprehensive, fully integrated digital model of a building that can be viewed, tested, quantified and adjusted throughout the design process.
Unlike 1990s-era computer-aided drafting, which merely automated traditional methods of representing architecture, BIM portends a cultural shift within the entire design and construction industry. As Birx explains, “We are assembling the building digitally, so we can solve the problems before we get to the actual steel and concrete.” This capability helps to reduce and eliminate the errors and change orders associated with drawings independently generated by architects, consultants and contractors.
The benefits of BIM begin as soon as design starts. As the model takes form, the project can be viewed in three dimensions, in elevations or along any cut line (horizontal, vertical and even obliquely if desired). This simultaneity allows architects to spend much more time designing instead of drafting and makes it quicker and easier to investigate alternatives, from structural systems to surface finishes, right at the desktop.
Using the old technology, architects spent as much as 60 percent of their hours on drafting tasks. BIM allows all of that time to be concentrated on getting the details designed correctly and coordinated with each other as well as with the engineers and contractors, as the BIM software creates the 2D drawings from the assembled model.
Using the virtual model, architects can produce more renderings and animated “walk- throughs” of higher quality earlier in the process, enabling clients to better understand how the building is taking shape. At the same time, clients can provide architects with more detailed feedback when adjustments to the design can be made readily.
For example, in one of the biweekly design meetings held by Ayers Saint Gross, a client indicated a preference for square columns over the round ones depicted in a three-dimensional image. Using BIM, the architects not only made the change to the drawing as the client watched, but also generated a revised cost estimate on the spot. Such preliminary high-quality visualization is also proving to be a boon to fundraising efforts as clients can now obtain more sophisticated renderings to show potential donors during the early stages of development.
The real benefit of BIM, however, is not just better imagery but better buildings. The software, for example, provides interference checking so that, at the press of a button, virtual objects occupying the same virtual space — perhaps an air duct in conflict with a structural column — are highlighted in red.
By catching these mistakes in cyberspace and correcting them on a daily basis, designers are able to reduce conflicts that might create problems later on. Birx maintains that such automated checking is one reason why Ayers Saint Gross has experienced a significant reduction in requests for information (RFI) during the construction of the firm’s BIM-designed projects. And fewer RFIs increase the likelihood that a project will be delivered on time and on budget.
At the same time, the virtual model provides an opportunity to study the effects of daylight, air flow and other environmental factors early in design to optimize building performance. And by keeping track of the type and quantity of materials, the technology can help minimize construction waste. These prospects suggest that BIM has the potential to play a powerful role in testing and applying sustainable principles to all buildings.
With BIM, the old distinctions between schematic design, design development, and construction documents fade away. The virtual model progressively evolves until it contains all of, if not more than, the information presented in a final set of construction documents. For some projects, Ayers Saint Gross must “save down” the three-dimensional BIM model into two-dimensional drafting programs to coordinate with contractors who are not yet BIM-ready. This process won’t be necessary once the entire industry is on board.
Already, Ayers Saint Gross has found contractors who are embracing the benefits of BIM. To build the University of Delaware’s Interdisciplinary Science and Engineering Laboratory, scheduled for completion in 2013, Whiting Turner is using the architects’ BIM files to create shop drawings and fabricate building elements, including structural steel and concrete, curtain walls and ductwork.
This sharing of information is revolutionizing the design and construction industry, leading to a new and improved way of building called Integrated Project Delivery (IPD) or Virtual Design and Construction (VDC). This approach allows a project’s key players, from architects and engineers to contractors, subcontractors, material suppliers and facility managers, to use the same virtual model as the basis of collaboration. The teamwork results in a much more efficient, less wasteful process of construction than in the past.
After a design is constructed, the virtual model continues to play an important role as a tool for managing buildings and planning renovations. Ayers Saint Gross has taken advantage of Revit® as a tool for assessing existing facilities at colleges and universities. The resulting model is used to evaluate the quality of spaces on the campuses and help strategize ways of using them to their fullest potential. It often provides the institution with a detailed building inventory on which to base future renovations and additions.
“Ayers Saint Gross has led the industry with the early adoption of BIM and IPD, and will continue to be at the forefront of the new technology,” says Birx. “Our clients will benefit from this improved process through lower costs, less construction waste and better buildings.”