MSG (Multidimensional Spectral Grids) synthesizes astrophysical spectra and photometric colors via interpolation in pre-calculated grids. Given a set of stellar atmospheric parameters (e.g., effective temperature, gravity, and metallicity), MSG calculates the specific intensity of the emergent radiation field as a function of wavelength and angle. It also convolves these data with appropriate filters and response functions to evaluate colors across various photometric systems.