As PIXAR was building the tools they needed to create Toy Story, they funded this work by selling some of these machines for Disney to use for visual effects in their famed "renaissance" cartoons. Like the wildebeest stampede in The Lion King.
However Disney needed these computer effects to blend in with their otherwise handdrawn movies, so we got a concept of "toon/cel shading"!
Typically Cel Shading consists of discretizing shading into bands, & some sort of edge detection.
1/2
On its own Cel Shading looks kind of ugly (though some video games have gotten away with it), lacking in the human touch it tries to evoke.
What recent films, since 2018's Into The Spiderverse, have found is that to make it work for a feature film we need to find ways to inject that human touch back into it.
Spiderverse used machine learning so artists could teach it how better to "ink" various video frames. I presume they trained a convolutional neuralnet on their own renders.
2/2 Fin!
Then Arcane took this to its logical conclusion by spending a quarter billion dollars to make every frame look like a renaissance painting. Definitely worth it.
"How do you texture it to look like a painting"
"We paint"
(quote from their making of documentary, "Arcane: Bridging the Rift")
