At TED2006, architect Joshua Prince-Ramus held our rapt attention as he deconstructed the process of building the Seattle Library, peeling back the collaborative “hyper-rational” process layer by layer. It was clear to us then that Prince-Ramus — U.S. director of Rem Koolhaas’ architecture firm, OMA — was poised to make a name for himself, independent of his mentor. (Note the pre-TED coverage in BusinessWeek Online.)

Now it’s official. Prince-Ramus has set out on his own, forming a new firm with business partner Erez Ella, and taking the entire New York OMA office and the majority of U.S. clients with them. Though the split was amicable, breaking up is always hard to do. “It ultimately became a clear decision, but not an easy one,” Prince-Ramus told The New York Times, which ran a full-page story yesterday. Said Koolhaas: “The sadness is something we deal with in private.”

The new firm, Ramus-Ella Architects (REX), will continue to oversee development of the Wyly Theater in Dallas and the Museum Plaza in Louisville (both of which Prince-Ramus walked us through in Monterey), as well as the Annenberg Center at CalTech. Good luck to you, Joshua! We’re looking forward to seeing you succeed!