I recently began consulting with an architectural firm who's work focuses on production housing. Production, what? For those reading this that design “real” buildings, you may not have ever heard this term before. For you, let me put it this way, Tract Housing. There is it. I said it. The homes that are build for everyone, but designed for no one.
It is not glamorous work and many in the architectural community do not consider it architecture. That is, architecture with a capital “A.” But, according to a June 18, 2013 press release from the NAHB (National Association of Home Builders) “Issuance of new building permits declined 3.1 percent to a seasonally adjusted annual rate of 974,000 units in May.” Even with a 3.1 percent drop, the number of new housing that requires architecture is huge. Someone has to provide that service and hey, it helps put a roof over our heads and food on the table.
The current trend in the architectural community is to utilize BIM, which stands for “Building Information Modeling” to generate construction drawings. Using BIM, an architect can “build” a building in the computer using objects such as walls, doors, windows, roof elements and actual fixtures or structural members. There are many advantages to BIM. The biggest is when changes are made they are instantly reflected throughout the plans. This saves time by minimizing coordination of revisions. It also allows for early 3D presentation models to update as changes in design development and construction drawing phases are made. Yes, revisions do happen. In addition, material and construction costs can be generated by using parametric objects that can be easily modified en masse and quantitatively summarized in schedules. BIM ultimately encourages the use of the computer as a design tool earlier in the process. This assists the architect in better understanding the overall composition of the building and helps the people paying for it, our clients.
Construction documents for production housing present challenges that do not exist with a set of plans for a single building. Sure they each contain floor plans, elevations, sections, etc., but production housing projects have multiple floor plans of varying sizes. Each floor plan will have several front elevations, which quickly multiply into dozens of variations that all have to be documented. These variations have many small differences as each elevation reflects a distinct architectural style. I use that term loosely as in most production housing the two car garage door dominates the front elevation, so the “style” of the home is communicated with contrasting exterior finishes, different window arrangements and trims plus varying rake and eave detailing. With BIM a model would be required for each home. A production housing project with four plans and four elevations per plan, quickly multiplies into 16 models. That is a lot of models to create for one project.
All of these differences can make generating BIM models a enormous task. Although I wonder, as I toil away manually inputing lines in CAD on what seem like hundreds of slightly different elevations, would spending time at the beginning of a project building multiple models pay off later when the inevitable client or contractor generated changes come along? It is possible to utilize BIM to overcome these obstacles?