Same as Fig. 2, but now comparing the results for the 12 M_⊙ ejecta model 2P-1D-smooth (thick dashed) with those from the 3D counterparts in which the clumping parameters ξ₀ and V_cl are varied (thick colored lines). We overlay the results from additional 1D smooth models in which the ejecta mass is progressively decreased by steps of 0.4 M_⊙ from 12 M_⊙ down to 7.6 M_⊙ (thin black lines), which produces a continuous sequence of events with a shorter photospheric-phase duration than model 2P-1D-smooth (see Sect. 7 for discussion).