This project is positioned within the general context of computer graphics, focusing on the creation of animated films. Its main goal is to investigate how computer tools can help capturing and reproducing the typicality of traditional 2D animations. More precisely, it plans to address the following challenges: 1) How to interactively generate in-betweening frames from a sparse sequence of rough drawings to swiftly explore different animation choices and motion designs. 2) How to stylize the geometry and motion of a 3D animation to allow its seamless integration into a 2D animation. In both cases, the proposed solutions should be compatible with regular animation workflows and provide adequate controls to artists that should remain at the center of the computer-human interaction loop. Ultimately, those solutions will be integrated inside the same software framework, allowing to produce 2D animations with a unified appearance starting from roughs drawings or 3D inputs.