Cartoons simplify shapes and give a wide audience the ability
to immerse into a simple, yet powerful form of art. Various papers
exist on the topic, mostly dealing with the application of 2D computer
graphics to cel animation [#!durand91toon!#,#!lit91animation!#,#!feke95toon!#].
This includes work on the so-called ``Multiperspective
Panoramas'' [#!EVL-1997-93!#], which are flat images that give
the illusion of a camera traveling through 3D scene (see Figure ).
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A complete framework for generating cartoon-style
renderings in real-time was presented by Lake et al. [#!lake00stylized!#].
The rendering process is divided into two parts: The painter
determines the shading information to fill the polygons, and the inker
highlights visible silhouette edges. Heart of the implementation is
a new cartoon shading model that uses solid colors which do not vary
over the materials they represent (see Figure ).
Shading is done with a color that is a darker version of the main
material color. Technically, the approach does not smoothly interpolate
shading across a model as in Gouraud shading, but finds a transition
boundary and shades each side of the boundary with a solid color.
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The cartoon framework also embodies a pencil-style renderer,
as well as the priorly mentioned inker, which detects and paints the
silhouette edges of the mesh. Furthermore, motion-lines (lines
giving hint of motion) are used to further emphasize animation. Another
aspect of cartoon animation are the view-specific distortions
of the models [#!EVL-1999-277!#] (see Figure ).
There is a deformation on the 3d mesh which cannot be captured with
conventional 3d models. Hence, the model has to change its shape autonomously
with respect to the eye point.
Another similar idea presented by Rubin et al. [#!SYMP_INTACT_3D-2001-2!#]
is to let objects be aware of their importance: Less important
items in the scene fade into the background, and are visually grouped
together with other objects in order to reduce their prominence (see
Figure ). On the other hand, important
objects stand out of the background and are thus emphasized (Figure
). This process of selecting areas
of high interest in a piece of art is widely known as composition.
[Distant objects are abstracted to form a single shape. The color is averaged over all objects.]
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