Observer dependent deformations in illustration

Illustration has some visual characteristics that are very interesting yet also very difficult to obtain with a computer. Whilst the simulation of the tools used for painting and drawing is successful enough, expressive capabilities have not been developed to the same extent. The deformations of objects and space is a major element in the expressiveness of illustration. The use of Hierarchical Extended Non-Linear Transformations is presented as a powerful tool for obtaining such kind of expressivity. Keywords: deformations, hierarchical extended non-linear transformations, illustration, animation, non photo realistic rendering dmartin@goliat.ugr.es y sgarcias@platon.ugr.es z jctorres@goliat.ugr.es 1 INTRODUCTION Since the beginning of computer graphics there has been a great deal of interest in producing images that are highly realistic, in physical terms, which is called photo realistic rendering. The main goal is to obtain images that are equal to the real ones. Over the l...