In recent years, several techniques have been proposed
       for automatically producing line-art illustrations. In this
       paper a new non photo-realistic rendering scheme for
       triangulated surfaces is presented. In contrast to prior
       approaches with parametric surfaces, there is no global
       parameterization for triangle meshes. So a new approach is made
       to automatically generate a direction field for the strokes.
       Discrete curvature analysis on such meshes allows to estimate
       differential parameters. Lines of curvature are then
       constructed to be used as strokes. Using triangulated surfaces
       allows to render aesthetically pleasing line drawings from a
       huge class of models. Besides, experiments show that even real
       time visualization is possible.