\page constructing_submeshes_page Constructing sub-meshes
-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.
+
\n Construction of a sub-mesh consists of:
<ul>
<li>Selecting a mesh which will encapsulate your sub-mesh</li>
-<li>Selecting a geometrical object for meshing</li>
-<li>Applying one or several previously described
+<li>Selecting a sub-shape for meshing</li>
+<li>Applying one or several
\ref about_hypo_page "hypotheses" and
\ref basic_meshing_algos_page "meshing algorithms" which will be used
-at computation of this sub-mesh</li>
+for discretization of this sub-shape.</li>
</ul>
<br><em>To construct a sub-mesh:</em>
From the \b Mesh menu select <b>Create Sub-mesh</b> or click <em>"Create
Sum-mesh"</em> button in the toolbar.
-\image html image33.gif
-<center><em>"Create Sub-mesh" button</em></center>
+<center>
+ \image html image33.gif
+ <em>"Create Sub-mesh" button</em>
+</center>
\par
The following dialog box will appear:
+\par
\image html createmesh-inv2.png
\par
It allows to define the \b Name, the parent \b Mesh and the \b
Geometry (e.g. a face if the parent mesh has been built on box) of the
-sub-mesh. You can define algorithms and hypotheses in the same way as
-in \ref constructing_meshes_page "Create mesh" menu.
+sub-mesh. You can define meshing algorithms and hypotheses in the same way as
+in \ref constructing_meshes_page "Create mesh" dialog.
+
+\par
+\anchor subshape_by_mesh_elem
+If the parent mesh is already computed, then you can define the
+\b Geometry by picking mesh elements computed on a sub-shape of interest
+in the 3D Viewer, i.e. you do not have to extract this sub-shape
+in Geometry module beforehand. To start element selection, press \a
+Selection button to the right of \b Geometry label. If this button is
+already down, then click it to release and then click it again. The
+following pop-up menu allowing to choose a way of geometry definition will
+appear.
+
+\par
+\image html choose_geom_selection_way.png
+
+\par
+<b>Direct geometry selection</b> enables selecting the sub-shape in the Object
+Browser.
+<b>Find geometry by mesh element selection</b> activates the following dialog.
+
+\par
+\image html find_geom_by_mesh_elem.png
+
+\par
+In this dialog, <b> Element Type </b> defines a kind of element to pick in the
+Viewer.
+Instead of picking an element in the Viewer, you can type its
+ID in <b> Element ID</b> field.
+<b> Geometry name </b> field allows defining a name of the sub-shape,
+with which the sub-shape will appear in the Object Browser (if not yet
+there).
\par
In the Object Browser the structure of the new sub-mesh will be
\par
It contains:
<ul>
-<li>a reference to the geometrical object on the basis of which the sub-mesh has been constructed;</li>
+<li>a sub-mesh name (\a SubMeshFace1)
+<li>a reference to the geometrical object on the basis of which the
+ sub-mesh has been constructed (<em>Cylindrical Face_1</em>);</li>
<li><b>Applied hypotheses</b> folder containing the references to the
-hypotheses applied to the construction of the sub-mesh;</li>
+hypotheses selected at the construction of the sub-mesh;</li>
<li><b>Applied algorithms</b> folder containing the references to the
-algorithms applied to the construction of the sub-mesh.</li>
+algorithms selected at the construction of the sub-mesh.</li>
</ul>
<br><b>See Also</b> a sample TUI Script of a
