PSF Generator is a software package that allows one to generate and visualize various 3D models of a microscope PSF. The current version has more than fifteen different models: 3D diffractive models: scalar-based diffraction model Born & Wolf, scalar-based diffraction model with 3 layers Gibson & Lanni, and vectorial-based model Richards & Wolf, and Variable Refractive Index Gibson & Lanni model. Defocussing a 2D lateral function with 1D axial function: the available lateral functions are: ”Gaussian”, ”Lorentz”, ”Cardinale-Sine”, ”Cosine”, ”Circular-Pupil”, ”Astigmatism”, ”Oriented-Gaussian”, ”Double-Helix”. Optical Transfer Function generated in the Fourier domain: Koehler simulation, defocus simulation.