The new workflow meant that everyone had to police unaddressed changes in the model. Team members would frequently e-mail screenshots of unaddressed conditions to the member responsible for the components that needed attention. In this way, progress became decentralized and organic, says the architect.

By the midpoint of the construction-document phase, the model was loaded with details and had reached a size that regularly crashed H3’s computers, even with top-of-the-line hardware and the latest software. H3 decided to remove “superfluous” details, such as base moldings and other decorative elements. The architect also decided to draw some exterior building details in CAD.

This fateful decision created a divided workflow and meant project knowledge was being deposited in two separate databases, defeating one of the potential efficiencies of BIM. Each database needed constant manual updating to stay coordinated and useful, which sapped the time of one team member.

“This is a misuse of labor that we now avoid on all projects by detailing with BIM,” says Van Nest. Another lesson learned is that only the details that are modeled become well-coordinated; those that were left in CAD triggered requests for information.

H3 learned something else. A complete model is a complex list of building-component dependencies, called hostings, says the architect. These need careful attention early in the project or teams will have to spend hours correcting unintended behaviors. For example, concrete panels hosted to exterior walls started showing up in the model as spanning multiple floors, which was not the intention. Changing the panels was simple, but deleting the overly tall walls to which panels were hosted resulted in those panels’ deletion as well. That was unacceptable to the architect. A new workflow was needed to carefully orchestrate complex copy-and-paste routines to let the panels survive the host transplant, reports Van Nest. “Even with successful transplant we needed to verify dimensioning and positioning, as unintended adjustments snuck in. This workflow resulted in doing many tasks twice,” he says, and weakened one of the promises of BIM.

H3 has learned that BIM project standards do not transfer best in a booklet or in any other printed way, like the CAD manuals the architect formerly handed to new employees. “As we build a library of families based on behaviors—adjustable angles for corner panels or adjustable-length wall elements—new team members need to be introduced to the assumptions and constraints of these families,” says Van Nest. A three-minute sit-down review per item is far more effective than any impersonal introduction to project standards, he adds.

Timothy Madeira, project manager for the owner’s agent, the Houston office of Jacobs, has a list of lessons learned on the courthouse project: Make sure the entire team has a clear understanding of BIM goals and limitations; Make sure construction terminology is clearly understood by all parties so goals can be clearly met; Make sure all parties involved with BIM have the same software and information; Provide adequate software and training; Have a BIM manager involved with the job, not just model integration.

“BIM is not a silver bullet and is not going to resolve issues on its own, though it may help clarify and illuminate other choices that may not have been previously evident,” says Madeira.

Kimsey isn’t cowed by BIM’s limits. GSA’s Sunbelt Region plans more with BIM to “put everything we can into the scopes of work,” he says. Contracts will say, ‘These are things you will do on this job if you are going to do the job.’”