The detail that jumped out at me is that most of the painting work was done before any brush touched the models. The maker assigned contrasting filament colors inside the slicer, using the cut tool with 'Cut to parts' enabled, so whole sections of the terrain came off the printer already in their base colors. For a full tabletop set that seems like a very smart way to cut down brushing time.
The set itself is the Container City: Founders Collection by WargameGeeks, printed on an enclosed Bambu Lab printer at a 0.20 mm layer height. The thick bridges setting was enabled for the railings, which strikes me as a sensible call for parts that thin and fiddly. The component list is genuinely varied: shipping containers, stacked containers, oil drums, ladders, walkways, scaffolds, skips and portable toilets, all built up as modular pieces for the new edition of Necromunda.
The finishing passes are where the colored prints get pushed into something grittier. Dirty Down Rust effect paint went onto the container panels with a brush, then was watered down to streak the rust downward. Artist's Loft Orange acrylic was sponged on over that, and Artist's Loft Silver metallic was drybrushed across container edges and the scaffolding. Most container pieces were sealed with Rust-Oleum Ultra Cover 2X Matte Clear, and the graffiti was drawn on with green Posca paint pens plus dual-tip brush pens, which looks like a fast way to get a lived-in industrial feel.
My one hesitation with the colored filament approach is that bare multicolor plastic can read as toy-like until the weathering goes on, so the effect really depends on those rust and sponge stages landing. I am also curious which pieces went without the matte clear, since only most of the containers were varnished.
Project by iPaintSmallThings. Watch it on their YouTube channel: