\n MESH module allows you to work with <b>Quadratic Elements</b>.
-Quadratic Edge is not a straight but a broken line and can be defined
-by three points: first, middle and last. All more complex \b Quadratic
-\b Elements differ from ordinary ones in that they consist of Quadratic
-Edges.
+Quadratic elements are defined by the same corner nodes as the
+corresponding linear ones, but in addition they have \a midside nodes
+located between the corner nodes on element sides.
+
+If a quadratic 2D element has an additional node at the
+element center, it is a bi-quadratic element (both TRIA7 and
+QUAD9 elements are supported). If a quadratic hexahedral element has 7
+additional nodes: at the element center and at the center of each
+side, it is a tri-quadratic element (or HEXA27).
+
+The convention of nodal connectivity of elements used in SALOME is
+the MED library convention. You can consult the description of nodal
+connectivity of elements in the documentation on MED library or
+\ref connectivity_page "here".
+
+There are several ways to create quadratic elements in your mesh:
+- manually (this way is described below);
+- use \ref quadratic_mesh_anchor "Quadratic Mesh" hypothesis to
+generate a quadratic mesh on your geometry;
+- convert an existing linear mesh to a quadratic one
+(see \ref convert_to_from_quadratic_mesh_page).
<em>To add a quadratic element to your mesh:</em>
<ol>
\image html image152.png
-\note All dialogs for quadratic element adding to the mesh
+\note All dialogs for adding quadratic element to the mesh
provide the possibility to automatically add an element
to the specified group or to create the group anew using
<b>Add to group</b> box, that allows choosing an existing group for
the created node or element or giving the name to a new group. By
default, the <b>Add to group</b> check box is switched off. If the user
-swiches this check box on, the combo box listing all currently
+switches this check box on, the combo box listing all currently
existing groups of the corresponding type becomes available. By
default, no group is selected. In this case, when the user presses
<b>Apply</b> or <b>Apply & Close</b> button, the warning message box
informs the user about the necessity to input a new group name. The
-combo box lists both \ref standalone_group "standalone groups"
-and \ref group_on_geom "groups on geometry". If the user chooses a
-group on geometry, he is warned and proposed to
-\ref convert_to_standalone "convert this group to standalone".
+combo box lists groups of all the
+\ref grouping_elements_page "three types": both
+\ref standalone_group "standalone groups",
+\ref group_on_filter "groups on filter", and
+\ref group_on_geom "groups on geometry". If the user chooses a
+group on geometry or on filter, he is warned and proposed to
+convert this group to standalone.
If the user rejects conversion operation, it is cancelled and
a new quadratic element is not created.
-To create any <b>Quadratic Element</b> specify the nodes which will form your
-triangle by selecting them in the 3D viewer with pressed Shift
-button. Their numbers will appear in the dialog box as <b>Corner Nodes</b>
-(alternatively you can just input numbers in this field without
-selection).The edges formed by the corner nodes will appear in the
-table. To define the middle nodes for each edge double-click on the
-respective field and input the number of the node. All edges and the
-object formed by them will be displayed in the Object browser. When
-all edges are defined you will be able to click \b Apply or <b>Apply and Close</b> button to
+To create any <b>Quadratic Element</b> specify the nodes which will
+form your element by selecting them in the 3D viewer with pressed
+Shift button and click \a Selection button to the right of
+<b>Corner Nodes</b> label. Their numbers will appear in the dialog box
+as <b>Corner Nodes</b> (alternatively you can just input numbers in
+this field without selection; note that to use this way the mesh
+should be selected before invoking this operation). The edges formed
+by the corner nodes will appear in the table. To define the middle
+nodes for each edge, double-click on the respective field and input
+the number of the node (or pick the node in the viewer). For
+bi-quadratic and tri-quadratic elements, your also need to specify
+central nodes.
+As soon as all needed nodes are specified, a preview of a new
+quadratic element will be displayed in the 3D viewer. Then
+you will be able to click \b Apply or <b>Apply and Close</b> button to
add the element to the mesh.
\image html aqt.png
-\b Reverse button for Quadratic Edges switches the first and the last
-nodes. For all other elements it reverses the element.
+\b Reverse button reverses the element.
</li>
</ol>
