Evolution in the R_gas(90%)/R_dust(90%) vs. R_dust(90%) space for some test substructured disks evolved with DustPy code in a low viscosity regime (α = 10^−3.5) for different values of the characteristic radius r_c. The points associated with each trajectory represent the snapshots taken at 0 Myr, 1 Myr, 2 Myr, and 3 Myr, respectively. Solid line: External photoevaporation (F_FUV = 4 G₀). Dashed line: No external photoevaporation (F_FUV = 0 G₀).