-/*!
-
-\page smoothing_page Smoothing
-
-\n Smoothing is used to improve quality of 2D mesh by adjusting the
-locations of element corners (nodes).
-
-\note Depending on the chosen method and mesh geometry
-the smoothing can actually decrease the quality of elements and even
-make some elements inverted.
-
-<em>To apply smoothing to the elements of your mesh:</em>
-<ol>
-
-<li>In the \b Modification menu select the \b Smoothing item or click
-<em>"Smoothing"</em> button in the toolbar.
-
-\image html image84.png
-<center><em>"Smoothing" button</em></center>
-
-The following dialog will appear:
-
-\image html smoothing.png
-</li>
-<li>In this dialog:
-
-<ul>
-<li>specify the IDs of the elements which will be smoothed:
-<ul>
-<li><b>Select the whole mesh, sub-mesh or group</b> activating this
- check-box; or</li>
-<li>choose mesh elements with the mouse in the 3D Viewer. It is
- possible to select a whole area with a mouse frame; or</li>
-<li>input the element IDs directly in <b>ID Elements</b> field. The
- selected elements will be highlighted in the viewer; or</li>
-<li>apply Filters. <b>Set filters</b> button allows to apply a filter
- to the selection of elements. See more about filters in the
- \ref filtering_elements "Selection filter library" page.</li>
-</ul>
-</li>
-
-<li>define the <b>Fixed nodes ids</b> that should remain at their
- location during smoothing. If a mesh is built on a shape, the nodes
- built on its geometric edges are always fixed. If the smoothing is
- applied to a part of the mesh (a set of element), the nodes on
- boundary of the element set are also fixed. It is possible to
- additionally fix any other nodes. The fixed nodes can be selected
- manually or by filters, just as the smoothed elements.</li>
-<li>choose the <b>Smoothing Method:</b>
-<ul>
-<li>\b Laplacian smoothing pulls a node toward the center of
-surrounding nodes directly connected to that node along an element
-edge.
-<li>\b Centroidal smoothing pulls a node toward the
-element-area-weighted centroid of the surrounding elements. </li>
-
-Laplacian method will produce the mesh with the least element
-edge length. It is also the fastest method. Centroidal smoothing
-produces a mesh with more uniform element sizes.</li>
-</ul>
-
-\image html image83.gif
-
-</li>
-<li>specify the <b>Iteration limit</b>. Both smoothing methods iterate
- through a number of steps to produce the resulting smoothed mesh. At
- each new step the smoothing is reevaluated with the updated nodal
- locations. This process continues till the limit of iterations has
- been exceeded, or till the aspect ratio of all element is less than
- or equal to the specified one.</li>
-<li>specify the <b>Max. aspect ratio</b> - the target mesh quality at
- which the smoothing algorithm should stop the iterations.</li>
-<li>activate <b>in parametric space</b> check-box if it is necessary to
- improve the shape of faces in the parametric space of geometrical
- surfaces on which they are generated, else the shape of faces in the
- 3D space is improved that is suitable for <b>planar meshes only</b>. </li>
-</ul>
-</li>
-<li>Click \b Apply or <b> Apply and Close</b> button to confirm the operation.</li>
-</ol>
-
-\image html smoothing1.png "The initial mesh"
-
-\image html smoothing2.png "The smoothed mesh"
-
-<br><b>See Also</b> a sample TUI Script of a
-\ref tui_smoothing "Smoothing" operation.
-
-*/