Length distribution of the filaments. The left and right columns refer to the Legacy MGS and LOWZ+CMASS sample, respectively. The rows are different smoothing cycles of the density field prior to filament detection. The red lines refer to a 3σ persistence threshold, and blue lines refer to a 5σ persistence threshold. The dashed and solid lines represent filament samples when no smoothing of the skeleton is applied after filament identification (marked “K0” in the legend) and when one cycle of smoothing is applied (marked “K1” in the legend), respectively. Although indicated as 5σ, the high-persistence cut for LOWZ+CMASS in the one-smoothing case has been limited to 4.5σ.