Optical long baseline interferometry (OLBI) is a powerful tool tostudy detailed stellar structures. Present optical interferometersattain the milliarcsecond angular resolution allowing this study.In the present contribution I present a physically coherentinterferometry oriented model which includes a radiation transfercode. An application of this model to rapid rotators is presentedwhere the effects of gravity darkening and geometrical deformationare included. The high angular resolution signatures due to rapidrotation are shown for several interferometric observables.