Maximum dust density in the ring as a function of the dust-togas mass ratio during gas removal for both a 2D (orange) and 3D (blue) viscous disk (α = 10⁻⁴). The upper x-axis indicates orbital periods at the reference radius of r = 1. Linear best-fit lines are shown for three stages of the gas evaporation process, with their slopes indicated next to each line. The slopes of the first two stages are consistent between the 2D and 3D case and then diverge in the final stage, where there is clumping in 3D.