The major task of computer graphics is to render images onto a
two dimensional screen according to the projections of the higher dimensional
underlying geometric and physical model of the objects. According to this
point of view, computer graphics is basically mathematics.
However, traditional geometry has difficulty in modeling natural scenes
because a cloud, a mountain, a coastline, or a tree is not a sphere, a cone,
or a cylinder that can be specified by several simple parameters[&make_named_href('',
As an extension to classical geometry, fractal geometry provides great potential
to model these natural forms once considered ``form-less monsters'' by
To model plant forms, there is still something missing. Not a static
structure, the shape of a living plant is formed in the framework of space and
time, as a process of growing based on the structure it already has. By
including the development in fractal models, Aristid Lindenmayer invented
a formalism that describes the growing of plants, known as L-systems
"node22.html#Lind68","[Lind68]")]. As an extension to the static fractal models, the most
significant features of this formalism are its simplicity and self-similarity.
An L-system is only a mathematical symbol formalism open to many interpretations.
For its feature of self-similarity, it can model the ``form-less'' patterns of
many natural growing processes. In the simulation of plant growing, we
interpret the symbols generated by the system as geometric elements of the
plants, such as branches and leaves.