Synthetic midplane luminosity profiles for a disc seen edge-on, in scattered light, for the standard μ = 2 × 10^-3 and e_p = 0 case and for different values of the disc’s average optical depth (i.e., collisional activity). The shown profiles correspond to a cut along the X axis when the planet passes at its maximum elongation along this axis (the planet’s location is marked by a black circle). Profiles are computed assuming a grey scattering function. The profile for the large parent bodies is directly derived from the PB runs presented in Sect. 3.1.