Non-Photorealistic Computer Graphics Library

Apparent ridges for line drawing

Author(s): Tilke Judd.
Master Thesis: Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.
[BibTeX] [DOI]

Abstract:
Non-photorealistic line drawing depicts 3D shapes through the rendering of feature lines. A number of characterizations of relevant lines have been proposed but none of these definitions alone seem to capture all visually-relevant lines. We introduce a new definition of feature lines based on two perceptual observations. First, human perception is sensitive to the variation of shading, and since shape perception is little affected by lighting and reflectance modification, we should focus on normal variation. Second, view-dependent lines better convey the shape of smooth surfaces better than view-independent lines. From this we define view-dependent curvature as the variation of the surface normal with respect to a viewing screen plane, and apparent ridges as the locus points of the maximum of the view-dependent curvature. We derive the equation for apparent ridges and present a new algorithm to render line drawings of 3D meshes. We show that our apparent ridges encompass or enhance aspects of several other feature lines. Description: Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 69-72). URI: http://hdl.handle.net/1721.1/38669 Keywords: Electrical Engineering and Computer Science.