Abstract: TicTacToon is a system for professional 2D animation studios that replaces the traditional paper-based production process. TicTacToon is the first animation systemto use vector-based sketching and painting: it uses an original method to transform a pen trajectory with varying pressure into a stroke of varying thickness, in real-time. TicTacToon provides resolution independence, a virtually infinite number of layers, the ability to dynamically manage perspective and sophisticated support for reuse of drawings. Other innovations include replacement of the rostrum model with a 3D model and integration into the overall 2D animation production process. TicTacToon is in daily use by 2D animation studios for a wide range of productions, from commercials to television series and even a feature film. The user interface enables professionals to sketch and draw as they do on paper. Over 100 professional animators have used the system over a period of two years and most need less than an hour before beginning productive work. TicTacToon eliminates most tedious tasks and frees professional animators for more creative work.