A potential complication to planet detection technique is caused by stellar surface inhomogeneities (due to the presence of stellar granulation, magnetic spots, dust, etc.) of the host star. 
Large efforts have been made in recent decades to use theoretical modelling of stellar atmospheres to solve multidimensional radiative hydrodynamic (RHD) equations in which convection emerges naturally. These simulations take surface inhomogeneities into account (e.g., granulation pattern) and velocity fields and are used to predict reliable observables.
3D RHD grid of simulations cover a substantial portion of the Hertzsprung-Russell diagram, including the evolutionary phases from the main sequence over the turnoff up to the red giant branch for low-mass stars.
Modeling the transit light curves implies the importance to have a good representation of the background stellar disk. I will present how the RHD simulations are used to model the temporal fluctuations of the granulation pattern for different kind of stars and how this affect the depth, the ingress/egress causing fluctuations that have to be considered as an intrinsic incertitude, due to the stellar variability, on precise measurements of exoplanet transits of planets with small diameters. In this context, 3D RHD simulations are essential for a detailed quantitative analysis of the transits. 
In this context, 3D RHD simulations are essential for a detailed quantitative analysis of the transits.