How They Made Rodger Rabbit...

[Pacman000]

https://www.cartoonbrew.com/feature-film/who-framed-roger-rabbit-hits-30-a-look-back-at-ilms-astonishing-old-school-optical-vfx-158471.html

"On set, practical gags and even robots helped ensure actor integration and eyelines would match the 2d characters that would later be animated by a team led by animation director Richard Williams. Their work, which included not only principal character animation but also drawn highlight, shadow, and other 'passes' – designed to give the characters more dimension – would be optically composited by Industrial Light & Magic (ILM)."