Another common misperception is that Building Information Modeling only produces one model per project. In practice, each trade makes its own model of the objects it controls. The resulting handful of models are collected and compared to deliver highly coordinated projects.

Architects still lead the modeling effort by first sharing a model with floor levels, column grids, and an origin for the common coordinate system. Then, while they build walls, windows, and doors, their structural engineer is free to make a separate model with columns, beams, and slabs. Other engineers start their models later.

As each professional models his part of the project, he can link the other professionals' models to his own -- much like he would link an AutoCAD X-ref. With this done, architects can place elements in the architectural model with confidence, knowing where beams and slabs have already been positioned.

As the models mature, they are routinely imported into software capable of a "clash detection." This means an algorithm is run to systematically catalogue each place individual models touch. Clash reports -- or lists of all the points of contact -- become critical documents in coordination meetings between an architect and his engineers. Common discoveries include beams passing through ducts, or misaligned fixtures.

Each clash detection is a potential change order in the field. Discovering them during the Construction Document phase has saved architects and owners hundreds of millions of dollars in the last few years. For this reason alone, savvy real estate developers and the US Government require their architects to deliver projects with BIM.

Next, learn how BIM is becoming a required delivery method on many new projects →