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Starting Small

Blach says the first model was physical and built to such a small scale that the highest building was only the size of a finger. "Daniel prefers to check his ideas by viewing physical models rather than those on the computer," Blach explains. "These early ideas consisted of very complex forms so it was easier and faster to build them directly. But almost simultaneously, we began building 3D computer approximations of the volumes."

The project designers began developing options in parallel as both physical and computer models. They built a 3D computer model in form-Z, a modeling tool known for its ability to create virtually any form. The physical-model builders used that data with computer-numerical-control (CNC) machines.

Blach says the firm began generating 2D plans, elevations, and section drawings very early in the design process. "We used VectorWorks from Nemetschek for all of our 2D work. We have found it to be ideal because it provides many powerful features within a user interface that is so simple it almost lets you forget you are working on a computer."

Making Presentations

For presentation renderings, the Libeskind team exported the 3D model into Adobe Photoshop to add finishes, people, trees, sky, and so on. These renderings were included in the final presentation to the LMDC along with the physical presentation model. The final physical model was assembled by the firm's own staff using Plexiglas facades that had been laser-machined by professional model builders using the 3D computer model data.

The 1,776-foot- (541-meter-) high tower is designed to represent the durability of democracy, and its top levels hold indoor gardens intended to serve as a confirmation of life. Additional buildings on the site house offices, a museum, a performing arts center, and a rail station.

A "wedge of light" funnels visitors to the memorial site. It represents, in plan, the positions of the sun on September 11 at 8:46 a.m. when the first tower was struck by a plane, and at 10:28 a.m., when that same tower was the last to collapse.

The competition jury that selected Libeskind's design said they felt it offered the maximum flexibility for a memorial. Rebuilding at "ground zero" and nearby areas is complicated by financial and legal considerations and construction is not expected to begin for another few years.

In the meantime, the Studio Daniel Libeskind is hard at work on the site-planning phase which involves the further refinement of the computer models by introducing new parameters and program information.

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Jerry Fireman is president of the Lexington, Massachusetts marketing firm Structured Information, which receives funding from Nemetschek.

Physical model of the World Trade Center design by Daniel Libeskind. Photo: © Jock Pottle Plans and other 2D drawings were developed in VectorWorks. Image: © Studio Daniel Libeskind Phasing of design and construction was explained through plans and simple mass models. Image: © Studio Daniel Libeskind Physical model of the site design. Photo: © Jock Pottle Lower Manhattan, displaying Libeskind's design concepts. Image: © Studio Daniel Libeskind   Click on thumbnail images to view full-size pictures.