I remember I played through the first Unreal at like 5fps
with the id fps's there was a clear evolution going from Wolfenstein to Doom to Quake. with Quake being the first one with a full 3D engine. I also remember games before Wolfenstein that had that same style of dungeon crawling through mazes of hallways. there were also a lot of flight sims and such on PC that had various levels of 3D graphics
on consoles it all started to come together during the 16-bit era. first with parallax scrolling and the "mode 7" effects on the SNES. and then later with 'Super FX' games like Starfox. guess I should also mention Donkey Kong Country and it's pre-rendered 3D models
it was also seen in movies from Tron to Lawnmower Man. obviously they weren't rendered in real-time, but it was clear that was the direction games were going
all that makes it hard for me to really put my finger on when this 'transition' happened. pretty much everything I mentioned was a
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moment. I remember being amazed by the spinning triforce in the menu for A Link to the Past