That's how any 3d animation works - up until the last run of design/rendering, they can pretty much manipulate everything in real-time as far as placing characters, syncing dialogue, etc. and once everything's good they actually render it with the real textures, facial expressions, highly detailed 3d models, lighting, etc
Back in the Toy Story days I'm pretty sure the first cut that was presented was practically stick figures moving around a vague blur
― mh, Wednesday, 20 November 2019 22:06 (four years ago) link