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Glass Refractive Index Matching (GRIM)

Interactive glass refractive-index-matching simulator: heat a silicone immersion oil until its index matches a forensic glass fragment and the Becke line vanishes -- the real GRIM technique used to compare crime-scene glass to a suspect.

Forensic Toxicology & Analytical Chemistry3DModerate60 FPS

A real glass fragment sits in a droplet of silicone immersion oil on a heated microscope stage. Choose a forensic glass type, then heat the oil and watch the refractive-index mismatch — and the bright Becke line tracing the fragment's edge — shrink toward zero exactly where the oil's index crosses the glass's own index. This is the actual GRIM technique crime labs use to compare trace glass evidence, right down to the rule that raising the objective sends the Becke line into whichever medium has the higher index.

⚙ Under the hood

Heat a silicone immersion oil on a simulated hot stage until its refractive index matches a forensic glass fragment and the Becke line disappears -- the real GRIM technique crime labs use to compare trace glass evidence.

forensicsopticsrefractive indexglass analysistrace evidenceGRIM

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