🔦 English Lighthouse: Fresnel Lens Prism Ray-Trace, Beam Focus and Flash Lab

Trace light from a lighthouse lamp through the 63 prisms of a Fresnel lens: refracting zones, total internal reflection prisms, lamp size, focus error and colour fringes decide the beam width, the peak candela, the flash seen by a ship and the luminous range. Blender-modelled lantern, tower and coast with a rotating beam.

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install