Inkwell, an experimental 2 1/2-D keyframe animation system, is the subject of this paper. Inkwell provides an intuitive user interface for creating and animating polygons, ellipses and splines. These primitives may be outlined and filled with a variety of patterns to create animated diagrams, graphs and charts, and simple characters and cartoons. Inkwell also has a patch primitive that facilitates deformation and animation of textured regions. The system provides editing features that include shape and timing control as well as digital filtering of parameters. Finally, Inkwell has deformation primitives that enable an animator to warp geometry in an intuitive manner. Inkwell was used to produce  Pigment Promenade , a computer animated short shown at SIGGRAPH 1990.
['Peter C. Litwinowicz']
Inkwell: A 2-D animation system