The Simpsons Movie all original characters, scenes etc are
hand-drawn, scanned, redrawn using computer, coloured and animated, the street shots IE when bart is skating to
krusty burger with chief wiggum chasing after him all the buildings are 3D made to look like 2D to blend into the film. also the truck that homer wins is also 3D made to look like 2D.
the principal of the simpsons mvie was to keep the hand drawn look. but with modern technology, making things 3D that Look like 2D can be easier to create.
landscape shots are all 2D cloes ups etc but more complext stuff Cars , building in the perspective distance are 3D to Look Like 2D, Futurama is also done in the same way.
Nobody uses cell anymore. 