For the first tower, FCRC formed a design team that includes architect-of-record SHoP Architects and multidisciplinary engineer-of-record Arup, both New York City. The team's initial charge for the first building, called B2 Bklyn, was to design a conventional tower.

The next assignment was to design a modular twin, indistinguishable in look and quality. For that, the B2 team expanded to include XSite Modular, a Brooklyn-based design-build consulting and management firm, formed last year. XSite and FCRC also are partners in a 100,000-sq-ft factory they are setting up a few miles from the Atlantic Yards site. XSite will manage and operate the plant.

The B2-modular design requires collaboration and coordination that would have been cost-prohibitive without building information modeling, says the team. BIM is used to both model and clash-check thousands of small elements that have to fit into tight spaces.

With the architect's construction management arm, SHoP Construction Services, as BIM integrator, the B2-modular team has developed a process that also relies on virtual design and construction (VDC) tools for scheduling and pricing.

In addition, the design team is developing production-level models and drawings for about 60% to 70% of B2-modular, to confirm dimensions and minimize area lost to risers and walls.

To maximize the value of design-level modeling work, the model is structured so that fabricators will not have to build a fabrication model from scratch for detailing, says SHoP. Also, when complete production-level documentation is provided for a scope of work, the subcontractor does not need to generate shop drawings, says Jonathan L. Mallie, a principal of both SHoPs.

Further, the SHoP model is designed to incorporate the extraction of bills of material. And detailed instructions can be created to help clarify work scopes for each of the subcontractors in the factory or the field, says Mallie.

The team's BIM-VDC workflow is designed to meet the needs of preconstruction coordination, quantity extraction, scope delineation and record drawings.

The same approach is taken to assemble the model as is taken to assemble the building. Subassemblies are modeled and inserted into a module. Modules are modeled and assembled into units. Units are assembled into subfloor groups, and subfloor groups are assembled into the federated model or apartment building.

A federated model, hosted by a web-based cloud application so that different team members can see it, allows users to input different-discipline design models for coordination and clash detection.

The goal is to complete as much of each module in the factory as possible. "We don't want workers in the field messing up the units," says David Farnsworth, an Arup principal.

All building systems were selected to minimize field mating. On site, about 95% of structural connections and 90% of mechanical-electrical-plumbing (MEP) connections can be done from the roofs of the modules, says Farnsworth.