Small bodies are witness of the early solar system. For the past ten years, observations from Earth, space and in-situ have allowed the determination of the shapes of an increasing number of small bodies (asteroids, satellites, Trans-Neptunians and dwarf planets). The shape determination precision improves every year, from the kilometer to the hundred meters using stellar occultations and spatial imagery. We present new methods to interpret these data in terms of internal structure that would potentially reveal information on the
formation conditions but also on the thermal and collisional history of these bodies.