According to Archinect,
"While filming on a set in New Orleans, actor Brad Pitt became seduced by the powerful image of a pink-clad CGI house within the lush Louisiana surroundings. He saw the pink structure as a metaphor, representing the future of renewed housing for those displaced by the recent disasters. With the vision fresh in his mind, he picked up the phone and described the concept to the Los Angeles office of Graft. A hurried telephone conversation was followed by a lengthy brainstorming session over a number of bottles of Pinot Noir. The master plan was confirmed, and work began the next morning."
Credit: Make it Right