Sketched interaction metaphors for character animation. Graphics group technical

sketch-based interfaces, character animation, skeletal animation The use of 3D virtual worlds is increasing rapidly and new tools are necessary to enable untrained users to create 3D content and interact with it. In this paper we present and evaluate sketch-based interaction metaphors for specifying complex animations of 3D skeletally animated models. Sketched interactions include bone rotation, motion path translation, sequencing and synchronisation of animations, and an undo-functionality. The sketches are drawn directly onto a model in a 3D view and are translated into time-dependent joint transformations. A user study demonstrates that the animation metaphors are intuitive, with the exception of animation ordering. More work is necessary to synchronise animations better. Overall our research demonstrates that sketched-based animations can be useful for applications requiring rapid prototyping containing a limited number of joint animations. Examples are the programming of household robots and the creation of simple animated scenes in education and social network applications.