Cartoon Character Modeling And Animating Based On Hand-Drawings

Appearance and motion of cartoon characters play the most substantial roles in cartoon animation. Most traditional cartoon animations are highly expressive, which are created by trained animators who design the appearance and the motion of charaters by drawing. In this process, a large amount of manual work is invested in drawing charcters frame by frame. On the other hand, the conventional computer animation techniques are based on 3D geometry model. User interfaces in modeling and animating follow the WIMP (window, icon, menu, pointer device) paradigm, which are cumbersome and daunting. The work of this thesis is to explore the modeling and animation generation approaches to create cartoon character animation with hand-drawn style, by combining the intuitive sketch-based interfaces and the efficient computer animation techniques. The main research topics of this thesis are as follows:1. Cartoon character modeling based on multi-view hand-drawings. Geometric modeling of character is a key issue in the process of character animation production. This thesis uses a hierarchical structure with mesh and skeleton to represent a character, and presents a character modeling approach based on multi-view drawings and domain knowledge templates. The input drawings are employed to create a complex character mesh matching the multi-view drawings, by combining surface optimization and surface subdivision algorithms. Then the approach constructs the skeleton subspace of the mesh by using heat equilibrium algorithm, making it easy to control the motion of the character. In addition, the batch modeling process of our approach is natural for traditional animators.2. View-dependent deformation and rendering of cartoon character. In traditional animation, a cartoon character often has a view-specific appearance, which cannot be captured with a conventional 3D model. This thesis improves the techniques of view-dependent geometry. For each key viewpoint, the approach deforms the character by skeleton pose reconstruction and surface optimization, yielding a set of models that closely match the hand-drawn reference drawings. Given a novel viewpoint, the approach generates a 3D model that is specific to the new viewpoint, and renders the model to achieve hand-drawn style by silhouette rendering and texture mapping. The approach can compute the correspondence of the base model and the strokes, reducing the amount of manual intervention required by the user in marking corresponding points.3. Cartoon articulated character animation driven by motion data. Motion data is increasingly used to efficiently generate realistic character animation. This thesis presents a data-driven approach for rapidly creating view-dependent character animation. The approach first creates a set of view-dependent models with different motion state annotations from hand-drawn drawings, and then trains annotation classifiers of the motion data by using support vector machines. Given an input motion data with the similar type, the approach extracts and annotates the keyframes, and retargets the hand-drawn style of the view-dependent models onto the input motion data by applying a heuristic generalization technique. The experiment results demonstrate the superiority of this method in generating cartoon character animation with hand-drawn style as well as original motion content.4. Cartoon facial expression modeling based on hand-drawings. How to generate abstract and exaggerated facial expressions with hand-drawn styles is a challenge in the field of computer animation. This thesis presents a hybrid view-and emotion-dependent approach to model cartoon facial expressions. A facial expression space model based on the viewpoint and the emotion is constructed from the multi-view drawings with facial expression, which can be semi-automatically generated by curve deformation. Given a novel viewpoint and an emotion state, the facial expression space model can be used to generate a view-dependent cartoon facial expression with the specified emotion.