smesh/doc/salome/gui/SMESH/input/adding_quadratic_elements.doc

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\page adding_quadratic_elements_page Adding Quadratic Elements

\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.

<em>To add a quadratic element to your mesh:</em>
<ol>
<li>Select your mesh in the Object Browser or in the 3D viewer.</li>

<li>From the \b Modification menu choose the \b Add item and select
one of the following:

\image html image152.png

\note All dialogs for adding quadratic element to the mesh
provide a possibility to add new element
automatically to the specified group or to create it anew using
<b>Add to group</b> box, that allows to choose an existing group for
the created node or element or to give the name to a new group. By
default, the <b>Add to group</b> check box is switched off. If user
swiches this check box on, the combo box listing all currently
existing groups of the corresponding type becomes available. By
default, no any group is selected. In such a case, when user presses
<b>Apply</b> or <b>Apply & Close</b> button, the warning message box
informing the user about the necessity to input new group name is
shown. The combo box lists both \ref standalone_group "standalone groups"
and \ref group_on_geom "groups on geometry". If the user has 
chosen the group on geometry, he is warned and proposed to
\ref convert_to_standalone "convert this group to the standalone".
If user refuses converting operation, an operation is cancelled and
new node/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
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.
</li>
</ol>



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