anon203597
key animation, genga (原画)
uncolored: https://sakugabooru.com/post/show/23064
finished: https://sakugabooru.com/post/show/23126
> How does the current process work;
This depends a lot on the production process used. These days it's anything between hand drawn frames with digital coloring to completely digital processes using 2D vector graphics or 3D models.
Plus this is far from perfect, it works best if you provide a lot of hinting and even then it produces results that may look pleasing enough but are not really close to what one has intended for a particular character design.
I would guess that it can be made good enough for some novelty videos but it's still far from professional production quality.
https://commons.wikimedia.org/wiki/File:William-Adolphe_Boug...