Echoes from the broad line region in active galactic nuclei (AGN) allow for the measurement of supermassive black hole masses outside the local Universe. However, the detailed structure of the broad line region is difficult to constrain due to the very small scales involved. With a new generation of high-quality reverberation mapping datasets, we can substitute time resolution for spatial resolution and begin to model echoes from the broad line region directly. I will discuss the development of a direct modeling approach for reverberation mapping data capable of measuring the absolute black hole mass and constraining the geometry and dynamics of the broad line region. We find that the broad line region emission comes from gas in a thick disk that is generally inflowing towards the black hole, although outflow is found in at least one case. Finally, I will discuss how this work can improve AGN black hole mass measurements at all redshifts.