IIRC from reimplenting 1/2 of the OpenGL pipeline in C for a CS course, the early Phong and Gouraud shadings inevitably looked either plastic, matte or dull.

IIRC from reimplenting 1/2 of the OpenGL pipeline in C for a CS course, the early Phong and Gouraud shadings inevitably looked either plastic, matte or dull. Hair and skin were hard but have been mostly solved fairly okay at great computational expense. And there's lots of hacks for things like oranges (bump mapping -> surface normal tweaks) and then they're shader languages. Each surface material (wood (especially chatoyance), textured marble, dull cloth, broken cement, butterfly wings (structural color/schemochromes), conchoidal broken glass, irregular dirt, dead leaves, pearlescent automotive paint, oil slicks (thin-film interference), on and on) needs slightly and/or completely different hacks to pull off the "Hollywood" real-time smoke-and-mirrors, least CPU/GPU/memory intensive fakery to render a believable scene whereas actual Hollywood can throw massive resources offline, at their leisure to render a scene frame-by-frame. Metal is extremely difficult to model because light travels oddly along crystalline and micro-fissure structures.