Three figures visualising our disk modelling approach concerning disk shape and dust settling. This particular model has two radial zones, with a (dust and gas-free) gap between r = 1 AU to r = 5 AU. The outer zone is featured by a tapered outer edge. The left plot shows the hydrogen nuclei particle density n_{⟨ H ⟩}(r,z). The middle and right plots show the local gas/dust ratio, and the mean dust particle size, respectively. These two properties are not constant throughout the disk, but depend on r and z through dust settling, see Sect. 3.5. From top to bottom, the two red dashed contour lines show the radial optical depth, in terms of the visual extinction, A_V,rad = 0.01 and A_V,rad = 1, and the two dashed black contours show the vertical optical depths A_V = 1 and A_V = 10. In the middle and r.h.s. plots, the vertical A_V = 10 contour line has been omitted.