you kind of can't but also kind of can the main texture is just a simple color for the outline it looks like they're using a duplicate of the mesh where it has been expanded, has flipped normals and a flat black material. if you google for toon rendering you should find some nice examples. Which engine are you planning to…
Good stuff :thumbs up: Does have imo a graphic toon aesthetic. EDIT: "...since you are a proper hard surface modeller " Nah! as perna might've mentioned for those of us who rely on throwing more geo at an issue, just a bunch of knuckle dragging subd heathens : p