/*!

\page creating_groups_page Creating groups

\n In MESH you can create groups of elements of different types. To
create a group of elements in the \b Mesh menu select <b>Create
Group</b>.
\n To create any group you should define the following:
<ul>
<li><b>Mesh</b> - the name of the mesh whose elements will form your
group. You can select your mesh in the Objet Browser or in the 3D
viewer.</li>
<li><b>Elements Type</b> - set of radio buttons allows to select the type of
elements which will form your group:</li>
<ul>
<li><b>Nodes</b></li>
<li><b>Edges</b></li>
<li><b>Faces</b></li>
<li><b>Volumes</b></li>
</ul>
<li><b>Name</b> field allows to enter the name of your new group.</li>
</ul>
SALOME Platform distinguishes between the two Group types:
<b>Standalone Group</b> and <b>Group on Geometry</b>.

\anchor standalone_group <br><h2>"Standalone Group"</h2>

<b>Standalone Group</b> consists of mesh elements, which you can define in
the following ways:
<ul>
<li>Choosing them manually with the mouse in the 3D Viewer. You can
click on an element in the 3D viewer and it will be highlighted. After
that click the \b Add button and the ID of this element will be added to
the list.</li>
<li>Applying Filters. The <b>Set filter</b> button allows to apply a
definite filter to selection of the elements of your group. See more
about filters on the
\ref selection_filter_library_page "Selection filter library" page.</li>
<li>By adding all existing entities of the chosen type to the
group. For this turn on the <b>Select All</b> check box. In this
mode all controls, which allow selecting the entities manually or by filters, are disabled.</li>
</ul>
To remove a selected element or elements from the list click the
\b Remove button. The <b>Sort List</b> button allows to sort the list of IDs of
mesh elements.
\n <b>Select from</b> set of fields allows to choose a submesh or an existing
group whose elements of the previously defined type will be added to
the list of elements which will form the new group.
\n <b>Color</b> - allows to assign to the group a certain color, for
example, defining boundary conditions. This feature introduces a
useful element of preprocessing in Mesh module. Note that <b>Color</b> attribute defines
the colors used for the display of the elements of the group. 
\n <b>Warning</b> The Med Color group interface may change in future versions of Salome.

\image html creategroup.png

For example, to create a new group containing all entities of the
existing group and some other faces selected in the viewer:
<ul>
<li> select the "Face" type of entities and input the name of the new group.</li>
<li> checks "Group" checkbox in "Select From" group.</li>
<li> select the existing group in the object browser or in the viewer.</li>
<li> click "Add" in "Content" group. "Id Elements" list will be filled
with IDs of faces belonging to the exising group.</li>
<li> select other faces in the viewer.</li>
<li> click "Apply" button to create the new group.</li>
</ul>

Please note that the new group does not have references to the source
group. It contains only the list of face IDs. So if the old group will
be changed, the new one will not be modified.


\image html image130.gif
<center>In this picture the brown cells belong to a group defined manually.</center>

\image html image131.gif
<center>In this picture the brown cells belong to the group defined by the criterion 
<b>Taper > 0</b>.</center>

<b>See Also</b> a sample TUI Script of a 
\ref tui_create_standalone_group "Create a Standalone Group"
operation.  

\anchor group_on_geom <br><h2>"Group on Geometry"</h2>

To create a group on geometry check <b>Group on geometry</b> in the \b Group
\b type field. <b>Group on geometry</b> contains the elements of a certain type
belonging to the selected geometrical object. To define a group select
in the Objet Browser or in the 3D viewer a geometrical object from
which the elements will be taken. After confirmation of the operation
a new group of mesh elements will be created.

\image html a-creategroup.png

\image html image132.gif
<center>In this picture the cells which belong to a certain face are
selected in green.</center>

<b>See Also</b> a sample TUI Script of a 
\ref tui_create_group_on_geometry "Create a Group on Geometry"
operation.

*/