Flex 2 generates detail — it creates super-high-resolution, high-bit-depth displacement/height maps (with matching diffuse and emissive channels) or instanced greebles from Geometry Nodes, then applies them across complex scenes incredibly fast. For example, generate one displacement map and blanket an entire distant city — hundreds of buildings wrapped in crisp sci-fi surface detail in seconds, and the scene stays light enough to render because the detail lives in the surface, not as millions of separate objects. SPOCK instead packs real, layered parts onto faces with part-by-part control (a layer of PCBs, then wires, then panels, then switches) — perfect for hero detail, but heavier. Rule of thumb: reach for Flex 2 to cover big or background surfaces with detail fast (even faster than SPOCK); reach for SPOCK to build rearrangeable, layered hero detail. They stack — pack SPOCK hero detail over Flex-displaced background surfaces.