/*!

\page viewing_meshes_overview_page Viewing meshes

By default a just \ref compute_anchor "computed" mesh will be
automatically displayed in the <b>VTK 3D Viewer</b>. (You can switch
off \ref automatic_update_pref "Automatic Update" preference parameter
to prevent this.)
Click <b>Display only</b> to hide all other objects at the same time.

<b>VTK 3D Viewer</b> is described in detail in the documentation on <b>GUI module</b>.

Use the following \ref mesh_preferences_page "preference parameters"
to adjust how the mesh is displayed by default:
- \ref automatic_update_pref "Automatic Update"
- \ref display_mode_pref "Default display mode"
- \ref quadratic_2d_mode_pref "Representation of the 2D quadratic elements"
- All parameters of \ref mesh_tab_preferences "Mesh" tab page of the
Preferences dialog.

After the mesh has appeared in the Viewer, you can select it with
left mouse click and  get information about it, change its
presentation parameters and access to other useful options by
right-clicking on the selected mesh.

\image html dialog.png

<ul>
<li><b>Rename</b> - allows to rename the object in the Object browser.</li>
<li><b>Hide all</b> - allows to hide all objects in the viewer.</li>
<li><b>Update</b> - refreshes the presentation of your mesh in the
  Object Browser, applying all recent changes. </li>
<li>\subpage mesh_infos_page "Mesh Information" -  provides
  information about the mesh.</li>
<li>\subpage find_element_by_point_page "Find Element by Point" -
  allows to find all mesh elements, to which belongs a point with the
given coordinates.</li>
<li><b>Auto Color</b> - switch on / off auto-assigning colors for the
  groups. If switched on, a default color of a new group in 
  \ref creating_groups_page "Create Group" dialog is chosen
  randomly. </li>
<li>\subpage numbering_page "Numbering" - allows to display the ID
  numbers of all meshing elements or nodes composing your mesh in the
  viewer.</li>
<li>\subpage display_mode_page "Display Mode" - allows to select between
  Wireframe, Shading and Nodes presentation.</li>
<li>\subpage display_entity_page "Display Entity" - allows to display
  entities by types (Faces, Edges, Volumes etc.).</li>
\anchor quadratic_2d_mode
<li><b>2D Quadratic</b> - allows to select between the representation
  of quadratic edges as broken \b lines or as \b arcs. A default
  representation can be set in \ref quadratic_2d_mode_pref "Preferences".
  Arc representation applies to 1D and 2D elements only.
</li>
<li><b>Orientation of faces</b> - shows vectors of orientation of
  faces of the selected mesh. The orientation vector is shown for each
  2D mesh element and for each free facet of a 3D mesh element. The
  vector direction is calculated by the first three nodes of the face
  produced by vectors n1-n2 and n1-n3.</li>
<li>\subpage colors_size_page "Properties" - allows to define several
  visual properties, including color of elements, shrink size, ...</li>
<li>\subpage transparency_page "Transparency" - allows to change the
  transparency of mesh elements.</li>
<li>\ref quality_page "Controls" - graphically presents various
  information about the mesh.</li> 
<li><b>Hide</b> - allows to hide the selected mesh from the viewer.</li>
<li><b>Show Only</b> - allows to display only the selected mesh,
  hiding all others from the viewer.</li>
<li>\subpage clipping_page "Clipping" - allows to create
  cross-sections of the displayed objects.</li>
<li><b>Dump view</b> - exports an object from the viewer in bmp, png
  or jpeg image format.</li>
<li><b>Change background</b> - allows to redefine the background
  color. By default it is black.</li>
<li><b>View Operations</b> - allows to show/hide the
  visualization toolbar in the Viewer window.</li>
<li><b>Recording Operations</b> - allows to show/hide the recording
  toolbar in the Viewer window.</li>
</ul>

*/