I’m looking forward to the new movies being released in December, particularly the next installment of “The Hobbit.” One film I doubt will be coming to a theater near you, though, is about urban pl
Defining BIM: Vision meets reality
In this second of a three-part series on building information modeling for home builders, Scott Sedam explains how BIM, when used properly, can be a powerful weapon in the war against waste in product and process.
3D models are only the beginning with building information modeling. BIM allows design and construction teams to incorporate a f
BIM: Not merely software
The seventh definition on the list declares that BIM is not merely software; it includes people, processes, standards, and methods. This takes BIM to a broader, higher level, into the realm of what is termed integrated product development (IPD), a great subject for a future article. But for now, keep the distinction that BIM is not software alone in the back of your mind. We tend to focus on the incredible capability of BIM software. Indeed, it is hard to watch a master with mouse and keyboard deftly manipulate a fully 3D plan without getting a grin on your face. Then he shows you the cost data embedded in the objects and your jaw drops. Finally, he demonstrates how the system interfaces with the schedule and you just shake your head in disbelief. Now we begin to forget about the key idea that BIM is not merely software but a process to drive communication and collaboration between all constituents in the building process, from day one of the project through completion.
The eighth definition is the observation that BIM is equated by so many managers as just another big bowl of WTF. Funny, for sure, but let’s use this for an even larger bowl of what author Jim Collins calls “objective current reality.” BIM is, at first, second, and perhaps even third glance, intimidating. Resistance is a logical response, and it is incumbent upon BIM disciples to plan for it and patiently help people through it. Yet the typical approach, as with virtually every high-tech solution, is for purveyors to take the potential users (thus potential buyers) on a deep dive through the incredible features of a BIM system. Now lost, the listener is left wondering what problem she was trying to solve in the first place. Once you know you have a solid handle on what BIM is, what it is not, and what it can do, you become a real hazard (if not an outright threat) to those who don’t yet share your knowledge. Take it easy, go slowly, keep harking back to “the end in mind,” and remember the principle of Shoshihn.
No part of the no-tears review in either this or last month’s article diminishes the promise of BIM. Evolving from a 2D world to full 3D can error-proof a structure at the beginning of the process, leaving our current trial-and-error approach behind with the margin-killing costs that accompany it. Each line of a plan now becomes smart, as it “knows” its own dimensions, where it’s located, and how it relates to every other line in the vicinity. Thus, when you pull, drag, spin, or look inside a 3D drawing, everything stays aligned, attached, and in perfect perspective. That in itself is no mean feat and requires considerable computing power. And that is only 3D. There is more, a lot more.
Now add objects to the plans, such as doors, windows, bathtubs, and cabinets. Make the objects smart by infusing them with information on how they attach, install, and impact all other building components. Imagine you decide to change the width of a window and it is able to warn you that it is now within the distance to the door that requires tempered safety glass, increasing cost substantially. Or you change the window height and it says “no can do” unless you change the structure, because there is no longer enough room for the required 10-inch header. Now the customer decides to add the bonus room option, and the system, by its own intelligence, knows to now increase the floor joists, add switches and outlets, reconfigure the trusses, add a door, and prompt you for a carpet choice, all in the most economical manner. This is not a fantasy; there are systems available right now that can handle it. But how? Who has time to embed the needed information in each and every object? Wait, it gets worse.
Beyond the third dimension
Now we move to what BIM developers usually call 4D by adding cost parameters, then 5D, which adds time/schedule. What do I mean by “usually”? Well, for example, I saw recently that two publications, one by the AIA and another by ASHRAE, switched the designations, using 4D for time and 5D for schedule. Sigh. Even though any student of physics automatically thinks of time as the fourth dimension, there is some logic to going with cost in the four slot, because it is the next most natural progression in home building. So let’s stick with that for now and imagine what happens when all dimension lumber “knows” how much it costs per foot. Should we use TJI or dimension lumber or web-truss? The system can cost it for you each way, quickly, and it even includes the tradeoffs of different mounting hardware, labor requirements, and impact on adjacent materials. Change from a cultured marble to a granite vanity top? Here is the cost. Customer wants a sliding pocket door? Here is the cost of the door upgrade, including the extra material for the double wall and the labor to build it. I could go on and on, but I trust you get the picture. Sounds a bit like Star Wars, I know, and again, how in the world do we get all of this information entered and linked up?
Now add in 5D with time requirements and full interface with the construction schedule. The customer picks the basement instead of the slab foundation. We not only just made major changes to the bill of material and cost, it simply takes more time to build on the foundation. And what if they select the fully-finished basement option? Even more time, cost, and impact on the schedule. A fully developed Lean builder may have his schedule so refined that he can maintain the identical days-to-build in each of these scenarios, but even so, this change requires significant crew resizing and balancing. In the most advanced BIM system, the system itself knows this and prompts the builders, suppliers, and trades to take appropriate action. As BIM advances, the system itself will be able to take the actions. Sound crazy? Well, this is old stuff in other industries, such as automotive.
Backing up a couple of steps, you can now see why every single object in the BIM 3D drawing must be “smart” and embedded with all required information. Who has the time to do that? While we are all going about our daily lives in traditional 2D CAD, there are monumental efforts taking place by suppliers and third parties to embed cost and time information into every SKU they produce. Pick a wood window — vinyl or aluminum — each one is a smart object in BIM. They know what they are, how much they cost, how they install, and how they might impact the schedule. The protocol has been established and most suppliers are deep into the process of converting their entire product catalogue.
From a perspective of Lean process, BIM looms as a great enabler, a powerful weapon in the war against waste in product and process. Conversion will not come quickly, but it will become easier in time. Recalling the sobering gap between the productivity growth of U.S. industry and the building industry, how can we not aggressively pursue any tool that helps us catch up?
Next month we’ll hear directly from those in the field that have been designing and implementing the BIM systems that we are all destined to use is some degree.
Scott Sedam, former home-building executive, well-known writer, and frequent speaker, is president and founder of TrueNorth Development. He welcomes your feedback at firstname.lastname@example.org.