Top panels: volume gas density in a vertical slice (r-θ), in units of M_A/au³ and logarithmic scale, obtained from a 3D model. The distributions are displayed at a phase of the binary orbit around apocenter passage (left), pericenter passage (center), and shortly thereafter (right). Middle and bottom panels: surface density of the gas, in units of M_A/au² and logarithmic scale, at the same orbital phases as in the top panels, obtained from the 3D model (middle) and from a corresponding 2D model (bottom).