Computer-Generated Pen-and-Ink Illustration
George Winkenbach, David H. Salesin.
Department of Computer Science & Engineering, No. 94-01-08b, University of Washington, Seattle, WA 98195, 23 June,
1994. [BibTeX]
Computer-Generated Pen-and-Ink Illustration
Author(s): George Winkenbach.
PhD Thesis: University of Washington,
1996.
[BibTeX]
Abstract:
This dissertation describes the principles of pen-and-ink illustration, and shows
how a great number of them can be implemented as part of an automated rendering
system. Illustration techniques in general, and pen-and-ink rendering in particular,
offer great potential for creating effective images from CAD models. And
with the computer’s ability to manipulate increasingly large models, communicating
complex information in an effective and comprehensible manner is becoming
an important problem. However, this potential remains relatively untapped in the
field of computer graphics.
After discussing principles of traditional pen-and-ink rendering, this dissertation
shows how the traditional graphics pipeline must be modified to support pen-andink
rendering. Then, it introduces the new concept of prioritized stroke textures.
Prioritized stroke textures form the central mechanism by which strokes are generated
so as to both convey a certain texture, such as “bricks”, and achieve a target
tone simultaneously. Prioritized stroke textures also have the advantages of being
resolution dependent; that is, they take into account both the resolution of the target
device, and the size of the image when generating the strokes.
A mathematical framework, and algorithms derived from it, for mapping stroke
textures on parametric free-form surfaces are also introduced. Rendering strokes
on parametric surfaces is not a simple problem, because the orientation of the
strokes must indicate the shape of the surface, in addition to accurately reproducing
tone and conveying texture. The solution proposed in this dissertation generalizes
the concept of prioritized stroke textures and allows the use of traditional,
image-based, texture mapping techniques. Thus, it extends considerably the range
of effects that can be achieved with stroke textures.
Finally, this dissertation describes two methods for building two-dimensional spacial
subdivisions of the visible surfaces from the 3D geometry. These “planar maps”
are needed during the rendering process for generating the outlines of the visible
surfaces, while taking into account adjacency, tone, and texture information. The
first method is relatively simple to implement, but is best adapted to polygonal
models. The second method is more appropriate for models containing free-form
surfaces.
Rendering Parametric Surfaces in Pen and Ink
George Winkenbach, David H. Salesin.
SIGGRAPH 96,
1996. [BibTeX]