{
  "_comment": "Glass look for three.js r170 MeshPhysicalMaterial on cosgral.pl (#050505 bg). Single source of truth: phone viewer (main.js) + cube_web*.glb (export_web.py). side=double renders the far grooves through the glass (dimmed by farSideDim); env = PMREM studio (strip power, sheen panels); edgeGlow = emissive boost on bevel/rounded faces; toneMapping Neutral keeps #050505 exact. Soap-bubble sheen: iridescence* = KHR_materials_iridescence (in the GLB); iridescenceNoise (swirl frequency, film thickness varies min..max over the surface) and iridescenceEdgeBias (weaker face-on, full at grazing/edges) are viewer shader tweaks - a plain GLTFLoader uses the max thickness everywhere.",
  "color": "#ffffff",
  "metalness": 0.0,
  "roughness": 0.0,
  "transmission": 1.0,
  "ior": 1.5,
  "thickness": 1.0,
  "dispersion": 0.7,
  "attenuationColor": "#f6f9ff",
  "attenuationDistance": 12.0,
  "clearcoat": 1.0,
  "clearcoatRoughness": 0.0,
  "specularIntensity": 1.0,
  "specularColor": "#ffffff",
  "envMapIntensity": 1.55,
  "edgeGlow": 0.15,
  "farSideDim": 0.52,
  "side": "double",
  "env": {
    "power": 2.0,
    "ambient": 0.02,
    "floor": 0.06,
    "sheen": 2.2
  },
  "toneMapping": "NeutralToneMapping",
  "exposure": 1.0,
  "iridescence": 0.55,
  "iridescenceIOR": 1.8,
  "iridescenceThicknessRange": [
    350,
    850
  ],
  "iridescenceNoise": 0.6,
  "iridescenceEdgeBias": 0.65
}