Iridescent Water Drop A drop of water turning slowly, refracting the room behind it and breaking into spectrum where its surface turns away from you. Transmission and Thin Film · 2026 How it is made The drop is genuinely transparent rather than painted to look it: a physical material at water IOR 1.333, which re-renders the scene into a buffer every frame so the surface has something to bend. The milky interior is not pigment but the backdrop, refracted and scattered by surface roughness on the way through. Because the object is the only thing in the scene, the environment it reflects is generated too - an equirectangular gradient with a single soft key, prefiltered through PMREM so roughness means something. Iridescence is handled twice over. Three own thin-film model is left switched on and its thickness varied across the surface by the same noise field that shaped the drop, standing in for a thickness map an icosphere has no UVs to carry; but that model tints only the specular term, which on a dielectric carries around four percent of the light face-on, so the visible spectrum is added on top from film thickness and viewing angle directly. Displacement is one low-frequency octave, and the shader rebuilds every normal from the deformed surface by evaluating it at two neighbours. Techniques: Refractive transmission · Thin-film interference · Procedural environment · Vertex shader displacement · Recomputed surface normals · Incommensurate motion periods This interactive WebGL sketch requires JavaScript.
