Abstract <p>The paper discusses models and methods for calculating the radiation of laser-electron generators of X-ray or gamma radiation based on the classical interaction model. The proposed model enables the calculation of the total flux, spectral brilliance, and polarization of the radiation with nonlinear effects taken into account. The latter inevitably arise when high-power laser pulses are used. For a set of model source parameters, it is shown that nonlinear effects lead to significant spectral broadening of both the fundamental and the higher harmonics. This results in substantial degradation of the spectral characteristics of the source and may require additional monochromatization of the working radiation spectrum. Modeling of the parameters of X-ray and gamma radiation from a laser-electron source has been carried out using collimator beam-shaping lines.</p>