Lotus Effect Simulator — Cassie–Baxter Superhydrophobicity

Lotus leaves stay dry not because their wax is unusually water-repellent, but because a forest of microscopic pillars lets a droplet rest on trapped air instead of the solid itself. This simulator renders that cross-section directly: a water droplet sits on a field of micro-pillars, with the true Cassie–Baxter equation computing how the apparent contact angle rises as the solid fraction shrinks and more of the droplet's underside touches air rather than surface. Switch to the Wenzel state to see the opposite regime, where liquid floods every groove and roughness instead amplifies the flat surface's own wettability — the contrast is why only air-trapping micro-texture, not roughness in general, produces true superhydrophobicity.