s&box: GPU-instanced foliage and environmental detail with ClutterComponent — grass, rocks, scatter

In s&box, scattering foliage, rocks, grass, and other environmental detail objects uses the Clutter system (ClutterComponent + ClutterDefinition). Developers try to manually place hundreds of GameObjects or use particle systems for environmental detail, missing the GPU-instanced Clutter system that handles thousands of objects efficiently.