Small Brain. Big Clean.

Individual seeded dry debris plus conservative wet films. Wheel movement transfers liquid into thinner trailing and outward streaks; limited suction removes mass. Film pickup and spreading use floorFilm, also used by training and sensors. All liquids share one persistent GPU-deformed mesh, preventing coplanar separate spill layers and mesh-replacement flicker. viscousSurface reconstructs a smooth height field, relaxes it over time, writes normals and blends material colours from actual cell masses. Reflective wetFilm PBR material. This is a finite-volume floor-film approximation with compute-driven viscous surface presentation, not a full 3D Navier–Stokes solver. A site counts clean below 0.001 mass; residual mass is not silently set to zero.