Visualisation of full box-size sections (8 h⁻¹ Mpc thick and 50 h⁻¹ Mpc wide in both directions) of the unsmoothed 3D temperature, pressure, total density, HI density, H₂ density, and metallicity fields (from top to bottom) at z = 0, for different SIMBA models progressively excluding feedback mechanisms (from left to right; see Table 1). It clearly shows a high level of morphological diversity. It also illustrates how individual feedback processes operating on galactic scales leave different morphological imprints on the gas fields at large scales; note for instance the influence of jets (second column) on the morphology of the T, P, n_H2, and Z fields, but not on n and n_HI fields. The corresponding 3D smoothed fields at z = 0 and z = 5 as used for the computation of the MFs are shown in Appendix B as well as Figures B.1 and B.2. The purpose of this paper is to compress the information content of all maps into a few numbers extracted from the MFs of their excursion and quantify how feedback impacts them across cosmic time.