  Acoustic guitar body shapes usually belong to one of a small number of
families of body shapes. However, these shapes are not standardized or even
precisely described in the literature on the subject. Rather, they are the
result of accumulated tradition and shapes vary so much that many common
components must be treated as effectively custom parts. Conventional curve fits
are not possible because the shape is not a single valued function. Numerical
descriptions such as spline fits will work, but the resulting data is too
cumbersome to be easily portable and may be dependent on choice of software.
Transforming the problem from rectangular to polar coordinates allows the use
of a closed form expression to describe a family of body shapes in a compact
and unambiguous way that is easy to implement in widely available software.
