3-D technology helps architects prevent mistakes and delays
- July 1, 2008
by Rab McClure
A few years ago, the National Gallery of Art in Washington exhibited a collection of architectural models built during the Italian Renaissance. The largest, a proposal for St. Peter’s Basilica in Rome, took seven years to build. It was 15 feet high, 24 feet long, 10 feet wide, and weighed more than six tons. Beautifully displayed so that it floated above the gallery floor, visitors were able to walk inside and beneath the model, experiencing the play of light and shadow on its intricately carved interior surfaces.
According to the exhibition catalog, “Architects [during the Renaissance] relied on these detailed scale models to assess and improve their designs, to guide workmen during construction, to make accurate estimates of building materials and to demonstrate for patrons and clients the final finished work.”
Clients today aren’t likely to wait seven years for a model. Still, the needs of today’s architects, owners and contractors remain similar to those addressed in Renaissance models. Architects require visualization tools that aid design. They also must communicate the intent of designs to contractors, predict cost and engage the building’s owners in dialog throughout the process. But the link between design and construction — something so evident in Renaissance models — has largely disappeared in the modern building process.
An increasingly accepted modeling technology may help re-establish that link. Building information modeling, or BIM, is a computer-driven design process aimed at revolutionizing how architects work. Software platforms such as Bentley BIM and Autodesk Revit allow design teams to build interactive virtual models for their plans. With BIM models, teams can easily visualize projects and everyone can be kept up to date on changes and modifications throughout the entire construction cycle.
Architects are adopting the technology at an increasingly rapid pace. Autodesk, for example, sold 100,000 copies of its program nationwide between 2000 (when it was introduced) and 2006. In 2007, it sold 100,000 copies in just 12 months. “The beauty of [BIM] is that it lets us think like architects again,” says Steven C. Wright, architect and design principal of Hanbury Evans Wright Vlatber that references that grid must be modified to reflect the change. Before building information modeling, all changes were done by hand, taking days. BIM software, such as Revit, makes those changes automatically, allowing designers to see quickly how the modification is affecting the project.
Hanbury Evans recently experienced these advantages during design of two residential colleges and a dining commons at Rice University. It was one of the firm’s first projects to rely totally on the system, and there were frustrations associated with the learning curve on the new software. However, the proof of its value came when the firm was awarded a second phase of work at Rice. The staff was asked if it wanted to continue with Revit or return to CAD drawings. The response was overwhelming: No going back.
To understand how BIM works, picture the difference between a traditional ledger and a well-designed electronic spreadsheet. Using the ledger, figures are recorded manually and tallied in a neat, organized manner. That information can be displayed in the same format using an electronic spreadsheet, with the obvious advantage that a change on any line is instantly carried through to the bottom line.
Like a more powerful and adaptable spreadsheet, a BIM model consists of three-dimensional objects, which are loaded with information and linked to other elements of the project. For example, a window in the wall of a BIM model contains a range of embedded physical characteristics, such as its height, width, material and distance above the floor — even Web-linked product data or cost information — that is codified elsewhere in the form of a window schedule. Specific information about the window shows up instantly on the schedule when the window is placed in the model. If the window size needs to be changed later, the new dimensions can be entered in the computer and the model adjusts automatically.
Another advantage BIM offers is “interoperability,” or the opportunity for each member of the design team to affect the model. Changes made in each area of design directly impact all others in the model, streamlining coordination. The mechanical engineer, for example, draws equipment and ductwork in the same model where the structural engineer draws beams, the lighting designer positions lighting and the architect details the ceiling system. This analytic advantage is called “clash detection.” Identified during the design phase, potential conflicts can be addressed before they become expensive, time-consuming headaches on the job site. Those construction headaches also can be costly. The Economist magazine reported in 2000 that, “Inefficiencies, mistakes and delays account for $200 billion of the $650 billion spent on construction in America every year.”
BIM promises to bring architecture up to speed with design technology used in other industries. “Virtual modeling for design has been used by automobile, aircraft and spacecraft designers for decades,” says Brian MacFarlane, associate principal and project director of health facilities at the Richmond office of Dallas-based HKS. The architecture firm has been using BIM software since its inception in the early 1990s.
Product manufacturers have long enjoyed the luxury of a more thorough research, development and prototyping process because of their ability to spread the cost of that investment over a large production run. Building design is critically different. The vast majority of architectural projects are built just once, with a steep learning curve associated with each new project.
BIM software sets the stage for real time three-dimensional visualization, bringing an architect’s work closer to the prototyping process used by product designers.
“BIM will have a huge impact on the construction industry,” predicts Carolyn Rickard-Brideau, a partner with Little Diversified Architectural Consulting in Arlington. “By enhancing communication between team members, BIM has enabled us to increase the degree of quality, consistency, and coordination in the design and construction of our projects, resulting in far fewer change orders — with an industry standard of 3 to 5 percent of the cost of construction, we, since switching to BIM, have reduced ours to one half to 1 percent.”
Good news for anyone contemplating a building project.