Section: New Results

Sketching dynamic and interactive illustrations

We collaborated with Autodesk Research in Toronto (as a scientific consultant) on a project whose focus was to design and develop tools that enable artists to bring life to illustrations with subtle, continuous animation effects and infusing interactive behavior to the drawings. We believe designers, artists and creators should be able to communicate with computers the way they think about art and animation. This motivated Autodesk to develop interfaces that facilitate powerful ways of thinking and content creation with freeform sketching and direct manipulation, thus offering an alternative to complex professional animation tools. Our design combines the complementary affordances of humans and computers by utilizing by-example phenomena, thus preserving expressiveness and personal style, yet reducing tedium.

The outcome of the collaboration is Kitty [23] , a sketch-based tool for authoring dynamic and interactive illustrations (Figure 2 ). Artists can sketch animated drawings and textures to convey the living phenomena, and specify the functional relationship between its entities to characterize the dynamic behavior of systems and environments. An underlying graph model, customizable through sketching, captures the functional relationships between the visual, spatial, temporal or quantitative parameters of its entities. As the viewer interacts with the resulting dynamic interactive illustration, the parameters of the drawing change accordingly, depicting the dynamics and chain of causal effects within a scene. The generality of this framework makes our tool applicable for a variety of purposes, including technical illustrations, scientific explanation, infographics, medical illustrations, children's e-books, cartoon strips and beyond. A user study demonstrates the ease of usage, variety of applications, artistic expressiveness and creative possibilities of our tool.

Figure 2. Example of a dynamic interactive illustration authored with Kitty. (a) Objects in the scene are interactive: the egg held by the cook can be dragged down, as if falling into the pot, triggering subsequent animations, such as soup splashes (b) and closing of the cat's eyelids (c). Turning the knob increases the fire and steam (d). The resulting dynamic illustration captures the living nature of the scene, where the gas stove flames burn and steam emits from the pot.

Kitty is a follow up of a previous project, Draco   [50] , a prototype sketch-based interface that allows artists and casual users alike to add a rich set of animation effects to their drawing, seemingly bringing illustrations to life such as a school of fish swimming, tree leaves blowing in the wind, or water rippling in a pond. Draco was realized before Fanny Chevalier joined Inria. Kitty is the result of a collaboration between Autodesk Research (inventor) and Inria (scientific consultant). A patent has been filed by Autodesk Research for Kitty, and the company is currently developping a commercial application based on the research protoype.