An unusual and record-setting building project is getting underway in Brooklyn.

Ground was broken Tuesday for B2, the first residential tower among the 16 structures planned for the Atlantic Yards development in Prospect Heights.

At a completed height of 32 stories, B2 is slated to be the world's tallest residential modular building.

About half of the 363 apartments will be affordable housing.

Despite the building's unique construction, the developer says it will blend right into the skyline.

Critics had also complained the housing took a back seat to Barclays Center, but developers say progress takes time.

"We built the arena, now we start on the housing, I always knew we would do that," said Bruce Ratner of Forest City Ratner Companies.

"This project was meant to be a model not just for New York but the country, of how large developments could be done," said Housing Advocate Bertha Lewis.

Half of the apartments in the building will be earmarked for low and middle-income residents.

The bulk of construction will occur at a factory at the Brooklyn Navy Yard. To move forward, the developer came to an agreement with the city's construction unions to fill the jobs there with unionized workers.

"We saw without that modular construction that these projects would more than likely not go forward," said Gary LaBarbera, Building and Construction Trades Council.

Developers say B2 is projected to welcome its first tenants in summer 2014. The rest of the buildings will be constructed when financing can be secured.