-Sub-mesh is a mesh on a geometrical sub-object created with algorithms
-and/or hypotheses other than the algorithms and hypotheses assigned to
-the parent mesh on the parent object.
-<br><br>
-If a geometrical sub-object belongs to several geometrical objects
-having different meshes or sub-meshes, it will be meshed with the
-hypotheses of a sub-mesh of a lower dimension.<br>
-For example, a face of a box is meshed with a sub-mesh using algorithms
-and hypotheses other than the parent mesh on the whole box. The face
-and the box share four edges, which will be meshed with algorithms and
-hypotheses of the sub-mesh on the face, because the face is a 2D object
-while the box is a 3D object. <br>
- If the dimensions are the same, an arbitrary algorithm/hypothesis
- will be used. This means that an edge shared by two faces each having
- its own different sub-mesh, will be meshed using algorithms and
- hypotheses of any of the two, chosen randomly. This indeterminacy can
- be fixed by defining \ref submesh_order_anchor "Sub-mesh priority".
-<br>
+By purpose, the sub-mesh is an object used to assign to a sub-shape
+different meshing parameters than those assigned to the main shape.
+
+Structurally, the sub-mesh is a mesh on a certain sub-shape, or a group of
+sub-shapes, possibly generated using different meshing algorithms
+and/or hypotheses than those used to generate the mesh on other
+sub-shapes.
+
+Creation of a sub-mesh allows to control individually meshing of a
+certain sub-shape, thus allowing to get mesh locally coarser or finer, to get
+elements of different types in the same mesh etc.
+
+A sub-shape to create a sub-mesh on should be retrieved from the main shape
+in one of the following ways: <ul>
+<li> In Geometry module, via <em>New Entity > Explode</em> menu.</li>
+<li> In Geometry module, by creation of a group (<em>New Entity >
+ Group > Create Group</em> menu).</li>
+<li> In Mesh module, by
+ \ref subshape_by_mesh_elem "selecting a mesh element" generated on a
+ sub-shape of interest. This way is accessible if the mesh is
+ already computed.</li>
+<li> In Mesh module, by clicking <em>Publish Sub-shape</em> button in a
+ dialog showing \ref meshing_failed_anchor "meshing errors".</li>
+</ul>
+
+Internally, definition of meshing parameters to apply for
+discretization of a certain sub-shape, for example an edge of a
+compound of solids, starts from searching an algorithm, 1D as for the
+edge. The following sub-shapes are sequentially checked for presence
+of a sub-mesh where 1D algorithm is assigned:
+<ul>
+<li> the \b edge it-self</li>
+<li> <b>groups of edges</b> containing the edge, if any</li>
+<li> \b wires sharing the edge</li>
+<li> \b faces sharing the edge</li>
+<li> <b>groups of faces</b> sharing the edge, if any</li>
+<li> \b shells sharing the edge</li>
+<li> \b solids sharing the edge</li>
+<li> <b>groups of solids</b> sharing the edge, if any</li>
+<li> the <b>main shape</b></li>
+</ul>
+(This sequence of sub-shapes defines priority of sub-meshes. Thus more
+local, i.e. assigned to sub-shape of lower dimension, algorithms and
+hypotheses have higher priority during the search of hypotheses to
+apply.)
+
+As soon as an 1D algorithm is found the search stops and the same
+sequence of sub-shapes is checked to find a main and additional 1D
+hypotheses the found 1D algorithm can take into account.
+
+The multi-dimensional algorithms have higher priority than
+uni-dimensional algorithms if they are assigned to sub-meshes of the
+same priority.
+
+If meshing parameters are defined on sub-meshes of the same priority,
+for example different 1D hypotheses are assigned to two faces sharing
+an edge, an arbitrary algorithm/hypothesis will be used for
+meshing. This indeterminacy can be fixed by
+\ref submesh_order_anchor "Changing" mutual priority of such
+concurrent sub-meshes.
+
