Introduction and Motivation
When we talk about animation in the context of this paper
we refer to animations where the objects and characters are
hand–drawn and resemble real life but do not mimic reality
exactly. Figure 1 for example shows some images of the type
of characters we would like to animate. As one can see the
characters can be playful, they can be a caricature or express
any other artistic feeling.
When looking at existing developments, the animator still
has to make great efforts to interact with the software. For
example, most drawings are made out of curves which only
can be manipulated by “point–click–and–drag”–procedures.
Hence, creating and especially editing strokes is a tedious
and unpleasant task, even for an experienced computer user.
Figure 2 shows the same girl as in figure 1(b) shown with all
the control points of the curves that make up the character.
It is obvious to see that due to the numerous control points
an animator easily will get lost trying to figure out which
control point to select in order to manipulate (a part of) a
particular curve. Even when the animator succeeds in selecting
the right control point, he finds it hard to find out