Both 2D and 3D animation have positives and negatives to them, like how
2D can be time consuming, or how 3D animation might not look as good
as it did the time it was made. But when brought together these two
completely separate styles can create beautiful things. Three best
examples of this idea is the ball room scene from the original beauty and
the beast. In this scene our main characters were renderee in 2D while the
background was created in 3D, our focus to stay on belle and the beast
while the rest of the ball room was used to enhance the scene. The second
example was the feature treasure island. 2D animation was used to bring
the characters and some environments to life. While 3D animation was
used to enhance the world around our characters, like the pirate john
silver whose cybernetic parts were rendere in cgi but blended to fit the
world. Or the ships and outer reaches of space being 3D to biring the
world to life. And the final example being the movie iron giant. The world
of the movie is all 2D while main focus of the film being the giant was
animated in 3d in order to give the giant an otherworldly feel among the
watercolor backgrounds and cel colored characters.
Witheach one of these movie the beautiful animation still holds up today
as it did when the films where in theaters, which shows the care and love
the teams of animators put into these films.