  2D animation is a common factor in game development, used for characters,
effects and background art. It involves work that takes both skill and time,
but parts of which are repetitive and tedious. Automated animation approaches
exist, but are designed without animators in mind. The focus is heavily on
real-life video, which follows strict laws of how objects move, and does not
account for the stylistic movement often present in 2D animation. We propose a
problem formulation that more closely adheres to the standard workflow of
animation. We also demonstrate a model, SketchBetween, which learns to map
between keyframes and sketched in-betweens to rendered sprite animations. We
demonstrate that our problem formulation provides the required information for
the task and that our model outperforms an existing method.
