Drawing and Animation Using Skeletal Strokes
Author(s): Siu Chi Hsu, Irene H. H. Lee.
Proceedings: Proceedings of SIGGRAPH 94, pp. 109--118, July,
1994.
[BibTeX] 
Abstract:
The use of skeletal strokes is a new vector graphics realization of
the brush and stroke metaphor using arbitrary pictures as 'ink'. It
is based on an idealized 2D deformation model defined by an
arbitrary path. Its expressiveness as a general brush stroke
replacement and efficiency for interactive use make it suitable as
a basic drawing primitive in drawing programs as well as
windowing and page description systems. This paper presents our
drawing and animation system, 'Skeletal Draw', based on skeletal
strokes. The effectiveness of the system in stylish picture creation
is illustrated with various pictures made with it. Decisions made
in the handling of sub-strokes in a higher order stroke and
recursive strokes are discussed. The general anchoring mechanism
in the skeletal stroke framework allows any arbitrary picture
deformation to be abstracted into a single stroke. Its extension to
piecewise continuous anchoring and the anchoring of shear angle
and stroke width are explained. We demonstrated how this
mechanism allows us to build up powerful pseudo-3D models
which are particularly useful in the production of 2½D cartoon
drawings and animation. Animation sequences have been made to
illustrate the ideas, including a vector graphics based motion
blurring technique.