Monroe Yorke — CAD Ring Viewer

The technique (v3.5): for each diamond mesh, build an SAH BVH with three-mesh-bvh. Wrap the mesh in a ShaderMaterial whose fragment shader is given the BVH as a uniform texture. Per pixel, cast the view ray, refract at the first facet (Snell's law), then trace up to N bounces against the BVH. Any bounce that fails Snell's condition becomes internal reflection. The final direction samples the HDRI equirect map. Spectral dispersion (new): instead of chromatic aberration on 3 channels, we sample 6 wavelengths across 400–650 nm, each with a physically correct IOR from the Cauchy formula for diamond (n = 2.378 + 0.0129/λ²). Weighted by wavelength→RGB response, this gives real diamond fire — the rainbow flashes you see on cut stones.

Photo lighting: on top of the HDRI, we add camera-locked "virtual" light sources baked into the diamond sample. When a diamond's exit ray points near the key light's world-space direction, we boost that pixel's brightness. Metal responds via real DirectionalLights targeting the same directions.

Bloom (new): the entire render passes through an UnrealBloomPass — bright specular highlights bleed outward, giving stones the "sparkle" perception that separates a photograph from a raw render.