3. System overview
Manipulating by hand each element of a sophisticated animation
rig easily becomes impractical when complexity increases. We
defined a user interaction model that eases the control process of
a 3D model based on a new approach (seeFig. 2). The user can
directly interact with the sketch-based User Interface (UI) tool. The
UI is connected to a transform based rig using a mapping method
between the UI tool output and the rig elements, which results in a
deformation in the 3D model. The user receives visual feedback of
the deformation in a 3D viewport window.