--- /dev/null
+/*!
+
+\page about_meshes_page About meshes
+
+\n \b MESH represents a discretization of a geometrical CAD model into
+a set of entities with a simple topology. In MESH there are two
+options of creation of meshes, you can:
+
+<ul>
+<li>generate meshes on the basis of geometrical shapes produced in the GEOM module,</li>
+<li>create your own meshes using the MESH functions destined for modification of generated meshes.</li>
+</ul>
+
+The topology of a mesh is described by the relationships between its
+entities including:
+
+<ul>
+<li>\b Node — 0D object of a mesh presented by a point with coordinates (x, y, z).</li>
+<li>\b Edge — 1D element of a mesh defined by two nodes.</li>
+<li>\b Face — 2D element of a mesh defined by three or four edges (closed contour).</li>
+<li>\b Volume — 3D element of a mesh defined by several faces.</li>
+</ul>
+
+ These entities are
+considered as topological entities and they don't
+imply any geometric representation. Only \b Nodes reference geometric
+representations of points with definite coordinates. The node entity
+will contain additional information about its position in the space
+and its relations with the meshed CAD model. Its position could be
+described in the following way:
+
+<ul>
+<li><b>2D position</b>. It is a free position defined by only two coordinates x,y.</li>
+<li><b>3D position</b>. It is a free position defined by three coordinates x,y and z. </li>
+<li><b>Surface position</b>. It characterizes the position of a node on a
+geometric surface and is defined by the u,v position in the parametric
+space of the corresponding surface.</li>
+<li><b>Line position</b>. It characterizes the position of a node on a
+geometric curve and is defined by the u parameter and the
+corresponding curve.</li>
+<li><b>Vertex position</b>. It characterizes the position of a node on a
+geometric point of the meshed CAD model and is defined by the x,y,z
+coordinates of the corresponding vertex.</li>
+</ul>
+
+<br><h2>Connections</h2>
+
+Each mesh entity bounds 0 or more mesh entities of higher
+dimension. In the same way each mesh entity is bounded by 0 or more
+mesh entities of lower dimension:
+
+<ul>
+<li>A node bounds edges, faces and volumes</li>
+<li>An edge bounds faces, and volumes</li>
+<li>A face bounds volumes</li>
+<li>A volume is bounded by faces, edges and nodes</li>
+<li>A face is bounded by edges, and nodes</li>
+<li>An edge is bounded by nodes</li>
+</ul>
+
+You can notice that there are two types of connections: \b inverse and
+\b direct connections.
+
+<br><h2>Inverse connections</h2>
+
+This relationship has a particularity that the order of bounded
+entities has not a direct meaning. Also the number of bounded entities
+is not fixed.
+
+\b Example: The edges surrounding a node. The 3rd edge has no more
+sense that the 5th one.
+
+<br><h2>Direct connections</h2>
+
+This relationship has a particularity that the order of bounding
+entities is meaningful. The number of bounding entities is fixed and
+depends on the type of the entity (hexahedron, tetrahedron,?).
+
+\b Example: An edge is composed of two nodes. A face is composed of 3
+or 4 edges depending if we are dealing with triangles or quadrangles.
+
+The connections are not only restricted to entities of one dimension
+higher or lower. For example some algorithms may be interested to
+retrieve all the faces surrounding a node.
+
+*/
