Geometry-Based2.5D Cartoon Modeling

Many computer-aided technologies in2D cartoon animation production hasappeared as computer graphics and image processing technology becoming mature,and they can be roughly divided into two categories: one is that using computer toassist some steps in the traditional process in2D cartoon animation creation, such asdrawing cartoon characters and in-betweens, etc.; another kind of technique subvertedthe traditional production process through3D modeling techniques, non-photorealisticrendering techniques and so on to generate2D cartoon animation directly, eliminatingthe process of drawing frame by frame. These two categories of technologies havetheir advantages and disadvantages, we combine the advantages of both technologiesand propose a geometry-based2.5D cartoon modeling method.In this paper we do not discuss the deformation algorithm itself, instead, wepredict the reasonable deformation result under some operation by analyzing theimplied geometry of the cartoon object that to be deformed, and then use deformationalgorithms render these effects. In2D cartoon animation, a character has an impliedgeometry, in this paper we define the character as an " cartoon object ",which iscomposed of" cartoon element", and each cartoon element only has one impliedgeometry, such as a planar, rectangular, sphere or cylindrical. We first analysis thetransformation of some simple geometries as the view angle rotates, and then usethese transformation result to calculate the corresponding deformation of the cartoonelements, which has the same implied geometry. The final deformation result of acartoon object is obtained by combining the deformation of each cartoon elements.This paper analyzes the transformation of planar, rectangular, spheres andcylinders’ projection when they are rotating, and designs algorithms to use thetransformation to achieve pseudo-3D rotating cartoon effect to prove the feasibility ofour method.