[en] Massive binary systems are crucial to improve our knowledge of the fundamental properties of massive stars, and synthetic spectra modelling with theoretical stellar atmospheres is commonly used in deriving some of these properties. However, the current stellar atmosphere models are designed for single spherical stars and therefore neglect interaction effects that occur in close binaries. We have developed a combined model that uses the TIDES code for computing the surface and the velocity field and the CoMBiSpeC model for the synthetic spectrum computation. This 2-in-1 model allows us to account for the interactions between the stars. We can now simulate the impact of the binarity on the spectra and refine the physical parameters of the binary systems. This model is presented here through the example of the spectral computation of Spica. In this particular system, the strongest effects due to the binarity appear in the line profile variations and the shape of the radial velocity curve.
