Comparison of the mass–size relation derived from our 3D catalog (blue points) and 2D catalog (red points) of molecular cloud properties. In 3D, M ∝ r ^2.9, while in 2D, M ∝ r ^2.1. We demarcate the 95% confidence interval with the thin semitransparent band around each best-fit line. We include four lines of constant volume density (n = 15, 30, 100, 300 cm⁻³) in dashed semitransparent black lines. The gray triangles represent the inaccessible volume and column densities, either due to the minimum volume and extinction thresholds required for inclusion in the 3D and 2D dendrograms (n < 25 cm⁻³ and A _K < 0.05 mag) or the inability of the 3D dust map to probe higher densities due to the map’s reliance on optical stellar photometry (n ≳ 100 cm⁻³ or A _K ≳ 0.2–0.3 mag).