A Technique for Animating Impossible Twisted Torus Figures

  Impossible figure is a figure which looks realizable at first glance, but is not actually realizable as perceived by the human eyes. When an impossible figure is represented as a three dimensional object, we can only view it from a specific viewpoint. However, researches in recent years enable such impossible figure to be viewed from various angles by representing it with computer graphics. Optical illusion object is a three dimensional object made to be an impossible figure when viewed from a specific viewpoint. The viewpoint that realizes an optical illusion object is called as an illusion viewpoint. An optical illusion object is not perceived as an impossible figure when a viewpoint moves away from an illusion viewpoint. However, recent researches have expanded illusion viewpoints in some kinds of impossible figures. This paper proposes a method to realize a representation of the impossible figure, which has not been dealt with in previous research, moved in a wide range of illusion viewpoints.