Perspective Contouring in Illustrative Visualization

Although traditional line illustrations are very abstract representations, they can communicate the form of an object effectively. This is only possible by the use of perceptual cues, mastered by professional artists. To create effective line illustrations from 3D models, it is important to use these perceptual cues to avoid visual dissonance and ambiguity, and also to create visual effects like shading, emphasis and depth perception. In this paper, we propose the adaptation of a technique called perspective contouring, used by illustrators to create emphasis in contour line drawings. The technique uses perceptual principles to manipulate line attributes, like width,spacing and length, around regions of interest determined by the user, creating the illusion that those regions advance towards the observer. The whole process is controlled through an intuitive sketch-based interface.