Inside a GLB File: Binary Format, Textures, and PBR

Logosofia no Dia a Dia · Jul 25, 2026 · 24m

Ever wondered why two GLB files of the same object can be wildly different sizes — one grey clay at 200KB, the other photoreal at 80MB? We crack open the binary format byte by byte. You'll learn the twelve-byte header, the JSON scene graph chunk, and the binary buffer chunk that holds vertex data. Then we dive into textured versus untextured models: embedded images with UV maps, material-only PBR values, baked vertex colors, and bare geometry. We cover the full PBR material set — base color, metallic-roughness, normal maps, ambient occlusion, emissive — and what visually breaks when each is…