The paper describes 11 principles of hand-drawn animation, and how they
can be used in 3D animation. They were attempting to solve the problem of
how to give appeal, life and mass to 3D animation, by applying well-known
principles:

squash/stretch -- which simulates mass
timing -- defines weight/size of objects by controlling action spacing
(per frame)
anticipation -- simulates inertia in preparing for an action
staging -- clearly composing a scene
follow through and overlapping action -- simulates continuing inertial
motion past the end of a specific action
slow in and out -- acceleration/deceleration is key to giving impression
of mass
arcs -- actions look more organic when they don't always follow a straight
path
exaggeration -- used to accentuate some (but not all) parts of a
scene/character
secondary action -- action resulting from another action. heightens
interest by adding complexity to character.
appeal/personality -- obviously, characters should have both of these in
order to be interesting

Contributions: This paper codifies the practice of creating cartoon
animation in 3D.