The GSA has had over 100 BIM models on a single project according to ENR -- and the count may reach 220!  I have been in more than 100 meetings over the past 4 years where people at the conference room table just wanted there to be 1 model that did everything and wanted me to say so.  But true to my beliefs, there is a need for more than 1 model.  There is also a need for a Services team to assist the customer in achieving his or her Construction Management goals, particularly when firms are tooling up their BIM skills and/or when an Owner mandates a project must be done in BIM.

The snippet below is excerpted from Nadine Post's 4-29-09 ENR article, "Digging into 3D Modeling Unearths Many Worms."  The article illustrates that user experience is exactly as I have been portraying it for 5 years.  It's good to hear someone else say it!

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BIM veterans also agree that modeling changes the design and construction process. The idea is simple: eliminate redrawing the drawings by putting information in once and using it over and over again; catch conflicts before construction begins rather than in the field, when construction dollars are being spent; and use VDC for estimating, scheduling and fabrication. The execution is difficult. BIM veterans caution rookies to hang on tight and expect the unexpected.

The redesign of the design process needs to take into account the order of construction and model content. It's important to resist the urge to model until protocols are worked out and the program is set.

Sources have learned the hard way that there are no minor design changes, especially if models have already been coordinated. For example, if an engineer moves a beam it can affect other systems, and their models, down the food chain. Models then have to be reviewed, adjusted, checked and re-coordinated.

In the best of all worlds, the contractor and prime trade contractors should be in the room during design process redesign and at times, during design. Input on cost, constructibility and schedule can save model rework and field problems.

Design-construction collaboration is not as easy in a traditional design-bid-build environment as it is with integrated project delivery, design-build and construction management at-risk. For an IPD hospital project for Sutter Health, 30 leaders of the building team spent nearly six months redesigning the design process, moving sticky notes around on a wall (see p. 28).

BIM means more time is spent on design. This can be irksome to designers if they are not compensated. Many maintain they are doing the contractors' work, without reward. Designers also find that to produce 2D drawings from BIMs they must revamp traditional in-house workflows to align with 3D model conventions.

BIM rookies should get help, define a process and expect the unexpected.

At BIM's conception, many expected there would be one BIM per building. The lesson learned is most BIM-enabled projects have myriad models. Many times the design model cannot be used by the trade contractor directly, thanks to software incompatibility or set-up, or both. Most often designers won't give their models to the contractor for fear of liability if there is a computer glitch or a dimensional inaccuracy. Those that do share usually issue a disclaimer, "Use this at your own risk, for reference only." That means the contractor has to check every detail of a design BIM. Often, the trade contractor's detailer finds it easier to create a model from 2D drawings produced from the design model.

On the courthouse project, there are more than 19 design BIMs and more than 60 construction BIMs. On the hospital, so far there are 125 models. That number is expected to grow to 220.

So much for the idea of one model per project. So much for the idea of entering information once and using it over and over again. So much for reducing the likelihood of human error while remodeling.

Sources advise that if BIM is a mandate from above, be sure to nail down owner's expectations for each building team member-especially if they are not outlined in a contract. Speak up if the expectations seem unreasonable or unreachable. Owners can be naive about BIM's capabilities.