Sunlight in Store for Downtown Subway Crossing

David Sundberg/Esto “It’s almost like you’ve taken the whole sky and folded it in,” said James Carpenter, the designer of the “Sky Reflector-Net” at the Fulton Center, under construction at Broadway and Fulton Street.

Most subway artwork sits within a station. Now comes a subway station that sits within an artwork.

David W. Dunlap/The New York Times

Or at least that’s how it may feel next year when the Fulton Center opens in Lower Manhattan and its artistic centerpiece â€" a curving, 79-foot-high net of reflective aluminum diamonds set in a stainless-steel tracery â€" sends ambient daylight into mezzanines, passageways and perhaps even passenger platforms.

The structure, James Carpenter’s “Sky Reflector-Net,” is the largest single work ever commissioned by Arts for Transit and Urban Design, a unit of the Metropolitan Transportation Authority. It has just been installed within the conical dome of the Fulton Center at Broadway and Fulton Street, designed by Grimshaw Architects. The center is the monumental headhouse for five stations serving the 2, 3, 4, 5, A, C, J, Z and R lines.

The “Sky Reflector-Net” cost about $2.1 million. The total budget for the Fulton Center is $1.4 billion, almost twice as much as the original estimate in 2003.

Above all, the artwork is intended to help travelers orient themselves within this labyrinth, which was constructed piecemeal over the years.

“When you’re coming up from the subway, the greatest way-finding aid is natural light,” said Craig Covil, a principal in the engineering firm Arup, which is working on the Fulton Center with Grimshaw and James Carpenter Design Associates.

David Sundberg/Esto A view of the net from within the dome.

The net’s 8,500-square-foot surface will change constantly, supplemented by prismatic glass blades suspended at the top of the dome that will scatter light rays through the interior.

Vincent Chang, a partner in Grimshaw, likened the effect to sun dappling. “It’s a visual movement that’s arresting to the eye,” he said. “Diurnally and seasonally, it will always be different.”

With that, Mr. Chang was interrupted, collegially, by Uday R. Durg, a senior vice president of the Metropolitan Transportation Authority’s capital construction division. “But what does it do for my passengers?” Mr. Durg asked.

“It’s a moment of respite,” Mr. Chang replied, “like at Grand Central Terminal, where you can stand at the balconies and watch the world go by.”

And that gets to things the “Sky Reflector-Net” may provide that transportation officials cannot measure: delight, astonishment, perhaps even awe â€" the “Wow” factor.

“We needed something magical downtown after all that had happened,” said Sandra Bloodworth, the director of Arts for Transit and Urban Design, during a tour of the Fulton Center last week.

She used the same adjective nine years ago, explaining that Mr. Carpenter had been picked to join the design team in part because his work was concerned with “how light moves across a space, the way it refracts and the way it reflects to create an atmosphere and environment that can be, at times, magical.”

Magic needs specs to get built.

The “Sky Reflector-Net” starts with a crisscross network of stainless-steel cables held between two enormous rings. The upper ring, under the skylight, is 53 feet in diameter and has been installed at a 23-degree angle. The lower ring, which is used to bring the entire net into tension, is 74 feet in diameter and tilted 12 degrees.

Among the cables, 952 perforated aluminum panels have been fastened. Most panels are diamond-shaped. Those at the top and bottom edges of the net are triangular. The largest diamond panel is a bit over eight feet tall. Each panel is slightly different than the next. They were numerically coded for proper installation.

The panels’ aluminum surface reflects about 95 percent of the light that strikes it, Mr. Carpenter said, but it is not a mirror. Instead, the surface is stippled, which ever so slightly diffuses the light. The amount of perforation varies.

The net was assembled by TriPyramid Structures of Westford, Mass., and hung in the Fulton Center in May. Except for an outlier or two, panel installation was finished last Friday.

David W. Dunlap/The New York Times Looking down through the net from the top of a boom lift.

Looking over the almost completed net on a rainy morning in late May, Mr. Carpenter described the effect of a clear day. “It’s almost like you’ve taken the whole sky and folded it in,” he said.

That sounded like designer talk; poetic, but hyperbolic. On a return visit last week, however, when the weather was clear, it appeared almost as if the whole sky had been folded into the dome.

In the end, the public’s impression will depend on how sensitively the retailing and dining spaces around the dome are designed. Commercial tenants at the Fulton Center will want to stand out. Conceivably, they could create enough visual distraction that the net’s subtle palette recedes.

But if “Sky Reflector-Net” stands out as clearly next year as it does now, “magical” may not be too strong a word.