/** 
\if OPENVOLUMEMESH_INTERNAL_DOC
\mainpage OpenVolumeMesh Documentation
\else
\page OpenVolumeMeshDoc OpenVolumeMesh Documentation
\endif

\image html volume_mesh.png

Welcome to the %OpenVolumeMesh documentation.

%OpenVolumeMesh is a generic data structure for the comfortable handling of arbitrary polyhedral
meshes. Its concepts are closely related to OpenMesh (http://www.openmesh.org). In particular,
%OpenVolumeMesh carries the general idea of storing edges as so-called (directed) half-edges over
to the face definitions. So, faces are split up into so-called half-faces having opposing orientations.
But unlike in the original concept of half-edges, local incidence information is not stored on a per
half-edge basis. Instead, all entities are arranged in arrays, which makes %OpenVolumeMesh an
index-based data structure where the access to entities via handles is accomplished in constant
time complexity. By making the data structure index-based, we alleviate the major drawback of
the half-edge data structure of only being capable to represent manifold meshes. In our concept,
each entity of dimension \f$n\f$ only stores an (ordered) tuple of handles (or indices) pointing to the
incident entities of dimension \f$(n-1)\f$. These incidence relations are called the top-down incidences.
They are intrinsic to the implemented concept of volumentric meshes. One can additionally compute
bottom-up incidences, which means that for each entity of dimension \f$n\f$, we also store handles to
adjacent entities of dimension \f$(n+1)\f$. These incidence relations have to be computed explicitly which
can be performed in linear time complexity. Both incidence relations, the top-down and the bottom-up
incidences, are used to provide a set of iterators and circulators that are comfortable in use.
As in OpenMesh, %OpenVolumeMesh provides an entirely generic underlying property system that allows
attaching properties of any kind to the entities. 

In this documentation, we first give a concise overview of the implemented concepts
in Section \ref concepts. In Section \ref iterators_and_circulators, we introduce
all necessary iterators provided by %OpenVolumeMesh. This library is additionally shipped with
a file format that allows for reading and permanent storage of the volumetric meshes from/to files.
Its specification can be found in \ref file_format. For information on the property system,
please refer to Section \ref property_system. Step-by-step tutorials and code examples can be
found in the tutorials section. %OpenVolumeMesh comes with a complete CMake build system
which facilitates building the library platform-independently. It is written in pure C++
using the standard template library and does not have any external dependencies except
for GoogleTest which is (optionally) needed for building the unit tests. As per default,
the unit tests are excluded from the build but can turned on as desired. Find information
on how to build %OpenVolumeMesh in Section \ref building_openvolumemesh.

\b Overview:

\li \subpage concepts
\li \subpage iterators_and_circulators
\li \subpage file_format
\li \subpage property_system
\li \subpage building_openvolumemesh

\b Tutorials:

\li \subpage ovm_tutorial_01
\li \subpage ovm_tutorial_02
\li \subpage ovm_tutorial_03
\li \subpage ovm_tutorial_04

**/
