Line Drawings of 3D Shapes (thesis)
Line drawings are commonly used for sketches, animations, and technical illustrations because they are familiar, simple, and easy to draw, yet wide-ranging and expressive.
However, current tools for computer generation of line drawings do not match the range and expressiveness available to a practiced human artist. In part, these failings are due to technical limitations of current algorithms. However, there is also a lack of formal understanding of how artists make drawings, and where these drawings are effective.
This thesis describes recent work on line drawings, including two studies aimed at a formal understanding of how people create and perceive line drawings of 3D shapes. In the first study, we asked artists to create drawings under controlled conditions, and in the second, we asked people to view the drawings and record their shape impressions using a series of gauge figures. We conclude that most of the lines artists draw can be explained by currently known definitions, and that line drawings based on these definitions can successfully depict shape, though they usually fall short of shaded depictions.
The final section of the thesis describes a system for drawing stylized lines, with two novel and important features: it includes an effect called stylized focus that can help direct the viewer's gaze to important parts of the drawing, and it is fast enough and has sufficient frame-to-frame coherence that it is suitable for rendering complex models interactively.
The presented results can be applied across computer graphics, with benefits to computer animation, visualization, design, and games.