Art lovers and curious passersby braved frigid winds yesterday to watch the unveiling of “Doug Aitken: sleepwalkers,” the first piece of artwork to be displayed on the exterior walls of the Museum of Modern Art.

As crowds circled the building, craning their necks to view the large-scale moving images projected on the museum’s steel and glass facades, area residents and shopkeepers adjusted to the altered cityscape.

“I think it’s pretty cool,” Mario Vega, who stopped to view Mr. Aitken’s work from the front steps of his office on West 54th Street, said. “It livens up the area. If I had a chair or it was warmer, I’d stay and watch it.”

Although the temperatures made viewing a bit uncomfortable, Mayor Bloomberg said the free public art project will help bring winter tourist dollars to the neighborhood.

“This is the kind of exciting event that draws New Yorkers to Midtown and tourists to our town,” he said at a press conference in the museum’s sculpture garden. “Arts and culture is a crucial driver of our economy.”

The film, shot in each of the city’s five boroughs, chronicles a night in the life of five New Yorkers. It stars singer-songwriter Chan Marshall, also known as Cat Power; Brazilian pop singer Seu Jorge; street drummer Ryan Donowho; actor Donald Sutherland, and actress Tilda Swinton. The installation will be visible every night between 5 p.m. and 10 p.m. until February 12.

“It’s interesting; it feels like we’re watching people’s lives,” an emergency room doctor from Chelsea, Marc Stoller, said. He watched the film from the empty lot between 53rd and 54th streets, which the museum had designated as one of four recommended viewing areas.

“Sleepwalkers” is the first of Mr. Aitken’s public art projects to be produced in America. In 2000, his installation “glass horizon” projected a pair of eyes onto the façade of the Vienna Secession building after it closed for the night. In 2001, he transformed London’s Serpentine Gallery into a multi-part video installation.