Introduction
David Breen, on of the foremost people in the field of computer cloth modeling, has this
to say on the reasons behind modeling cloth:
“The drape of woven cloth has intrigued humans for centuries. This is evident
in the flowing robes contained in the sculptures of ancient Rome, the intricate folds
of fabric depicted in the paintings of the Renaissance, and the elaborate billowing
clothing of the 18th century. Even in the modern times artists such as Christo realize
that the image of draping cloth over a structure like the Reichstag in Berlin is
fascinating and provocative. It has always been clear that woven materials have unique
properties that allow them to deform in ways significantly different than other sheet
, eg: paper, vinyl and metal foils. Cloth’s special deformation capabilities have been
noted and recognized through the ages but never fully understood from scientific or
engineering perspective.”
David Breen
I think this statement by Breen is a good way to introduce cloth modeling. Cloth isn't like
most materials. It does not have a simple static form that can be modeled simply by using
geometric shapes. The shape of cloth changes depending on the situation the cloth is in. Because
of the complexity in the shape that cloth conforms to unique methods must be created. Many
different methods have been used in an attempt to simulate cloth. A few of these methods will
be discussed in this webpage.
There are three different types of cloth modeling: Geometric based, physical based and hybrid
techniques. The gemetric based modeling technique focuses on creating realistic apearances such as
folds and creases. These techniques usually require a considerable degree of user intervention.
The Physical based technique usually represents cloth models as triangular or rectangular
grids with points of finite mass at the intersections. The various forces and energies are
calculated in relation to the other points. This method incorporates both energy-based and force-based
methods. The energy based method calculates the energy of the whole cloth from a set of equations and
determines the shape of the cloth by moving the points to achieve a minimum energy state. The forced
based method represents the forces among points as differential equations and performs a numerical integration
to obtain the oint positions at each time step.