Cassie-Baxter Self-Cleaning Coating Simulator (2D)

This 2D companion to the 3D nanopillar-coating simulator models the same real superhydrophobic surface physics, computed a genuinely different way: instead of a single orbitable 3D scene, it lays out a theory chart of the Cassie–Baxter apparent contact angle θ* and the Furmidge roll-off angle α_c plotted against solid fraction f_s, a tilted side cross-section of the nanopillar array with a rolling droplet, and a separate pannable/zoomable top-down dust map. Tune pillar height, pitch and radius-to-pitch ratio to move along the f_s axis and watch θ* and α_c update on the curve; tilt the panel past α_c and the droplet in the cross-section starts rolling downhill, sweeping dust off the array in the top-down view exactly as a real self-cleaning solar coating would in the rain.