Rendering artistic and believable trees for cartoon animation

We present a novel approach to design artistic and believable trees in a cartoon-like style, which can be rendered by an animated camera to produce a convincing 3D-like experience. While computer assisted traditional animation is able to generate the desired effects, this approach still depends too much on the creation of many hand drawn images. Existing approaches fully depending on 3D geometries, on the other hand, give little artistic freedom and have difficulties to avoid artifacts popping up in successive frames. In order to provide good solutions to these difficulties, we present a hybrid (2.5D) framework, combining the advantages of both 2D and 3D approaches. From an underlying 3D geometry we get the necessary information to obtain an acceptable level of 3D behavior and a good frame-to-frame coherence. In the same framework, 2D artistic input is employed to obtain any desired 'look', both of the rendering and of the animation.