Density projections along the z-axis for two snapshots of simulation HIIR+PSJ, at 2.3 Myr (left) and 3.15 Myr (right). White dots mark the sink particles’ positions. The left panel captures the formation of the central hub, with three filaments converging into it. In the right panel we can see how the giant H II region, originating from the lower-left filament, restructured the cloud after about 0.4 Myr.