The newest buzzword and hot button in our industry is BIM, or Building Information Modeling. BIM has not yet replaced green building as the hot topic, but it is closing fast. It’s just another one of those things that we as subcontractors have to worry about in these troubled times. Unfortunately, we as a people have a tendency to speak in acronyms without really understanding what the acronym stands for. Factoring in the technology all around us, it is not surprising that some things go by unnoticed until we come face to face and have to act on it. The “it” is this case is BIM, and just what is BIM?
If we take a hard look at the name, it’s nothing new to us and our industry. We, the construction and design industry, have always been involved in management of information concerning buildings. When I started as a draftsman for the old Virginia Department of Highways, which is now the Virginia Department of Transportation, we used ruling pens and crow quill pens to produce ink on linen drawings for the Interstate Highway System. We had a standard set of specifications and standard drawings to work with. Ah, if we could only apply that methodology to buildings. Together these items were used by the contractors to build the highways. While the medium varied and changed somewhat with the introduction of Mylar® and ink pens with graduated widths, nothing really changed in how the information was presented.
Sometime in the late 1970s and early 1980s, overlay drafting was introduced. This involved using a register bar to ensure that the information on the base drawing was transferred to the overlay. Working from a baseline drawing, overlays of the different disciplines were produced in an effort to eliminate conflicts and increase productivity. These drawings were produced by experienced draftsmen under the direction of an experienced chief draftsman who knew and understood how the parts of a building went together. In some cases, a firm would have a standard set of details to use. In other words, they didn’t re-invent the wheel for every new project. Manufacturer’s technical representatives were consulted to ensure that the details were correct and would not present problems during construction. I remember brining in contractors to conduct a peer review of the drawings during the construction document phase.
This same methodology prevailed until the introduction of Computer Aided Design in the 1980s. Even then the use of CAD was limited to very few firms. I think the average cost of a workstation was between $15,000 and $20,000, which represented quite an investment for any firm. So now we have building information management taking on a different form; However, it’s the same information that was conveyed using manual techniques.
With the use of CAD firmly ensconced in our profession, technology moved ever forward and now it brings us to BIM. In a simplified approach to defining BIM, the information that once was produced manually is now compiled by a computer using a specific piece of software. It’s the same information that was produced manually for many years, but now this information is stored in a digital format that produces drawings quickly. With BIM in its current state, there is the ability to produce the information in ways that were possible with the manual techniques but were costly and not always a true representation of the conditions.
For example, there have always been perspectives or renderings produced by an accomplished artist showing one or two views of the exterior and maybe the interior of the building. Using BIM it is possible to produce 3D views taken from anywhere in the building. Some years ago the U.S. Army Corps of Engineers used a CAD modeling system to produce a video of a proposed building in Vicksburg, Miss. This video was made available to the contractor for use during construction. The video actually showed pieces of the building going together. The contractor’s superintendent later said the video really helped him understand parts of the building that were not apparent from the 2D drawings.
This is where BIM becomes interesting and useful in the field. I recently read an article were a contractor posted 3D views of the work on the wall so the mechanics could see what the proposed finished product should look like. The 3D views also have the potential to avoid conflicts prior to beginning construction. The drawback to all of this is the information used to produce the drawings. Remember the old acronym GIGO—Garbage In, Garbage Out? The wall and ceiling industry needs to provide input to make sure that the information coming out is not garbage. The question is, how can the wall and ceiling industry have an impact on the data used for BIM? Remember that the producers of the software have very little contact with the people who use the end product—the contract documents. Their focus is on the designers who produce the contract documents. AWCI will be exploring this subject next month at our convention in Nashville, Tenn., in an educational program called, Building Information Modeling for AWCI Members: Fact or Fiction. Plan on being there.
Donald E. Smith, CCS, is AWCI’s director of technical services. Send your questions to [email protected] or call him directly at (703) 538.1611.
