FG-Nup packing creates channel in the center of the lumen. Two-dimensional histogram of filament locations normalized over a 100-ms simulation in a 4-nm slice through the center of the NPC under FG4 bond strength (A), FG5 bond strength (B), FG6 bond strength (C), FG7 bond strength (D), and no FG bonds (E). The scale goes from 0 to 5 and indicates the mean number of filaments in that spot over the time course of the simulation. (F) The fraction of filament mass that is located within the lumen of the NPC. Plot is mean ± SD.