2DToonShade: A stroke based toon shading system.

•A semi-automatic method for creating shades and self-shadows in cel animation.•Tool designed to stay as close as possible to the natural 2D creative environment and therefore provides an intuitive and user-friendly interface.•Shade enhancement system allowing the deformation of shades around detail strokes, such as, but not limited to, facial elements or cloth folds.•An efficient and robust propagation technique allowing the reduction of the effort required to create plausible shades and local self-shadows in a hand-drawn animation.