Edge-on density distribution of all disc particles (thin+thick) at the end of the simulation run (t = 9 Gyr) for all thin+thick disc models with varying f_thick values. Black dotted lines denote the contours of constant density. Left panels show the density distribution for the rthickS models, whereas middle panels and right panels show the density distribution for the rthickE and rthickG models, respectively. The thick disc fraction (f_thick) varies from 0.1 to 1 (top to bottom), as indicated in the left-most panel of each row. The bar is placed along the x-axis (side-on configuration) for each model. The vertical black dashed lines denote the extent of the b/p structure in each case (for details, see the text in Sect. 3.1.2).