Node quality controls:
<ul>
<li>\subpage free_nodes_page "Free nodes"</li>
+<li>\subpage double_nodes_control_page "Double nodes"</li>
</ul>
Edge quality controls:
<li>\subpage free_borders_page "Free borders"</li>
<li>\subpage length_page "Length"</li>
<li>\subpage borders_at_multi_connection_page "Borders at multi-connection"</li>
+<li>\subpage double_elements_page "Double edges"</li>
</ul>
Face quality controls:
<li>\subpage warping_page "Warping"</li>
<li>\subpage skew_page "Skew"</li>
<li>\subpage max_element_length_2d_page "Element Diameter 2D"</li>
+<li>\subpage double_elements_page "Double faces"</li>
</ul>
Volume quality controls:
<li>\subpage max_element_length_3d_page "Element Diameter 3D"</li>
<li>\subpage bare_border_volumes_page "Bare border volumes"</li>
<li>\subpage over_constrained_volumes_page "Over-constrained volumes"</li>
+<li>\subpage double_elements_page "Double volumes"</li>
</ul>
To manage the quality controls call pop-up in the VTK viewer and select "Controls" sub-menu
--- /dev/null
+/*!
+
+\page double_elements_page Double edge, Double faces and Double volumes
+
+These mesh quality controls highlight the mesh elements basing on the same set of nodes.
+
+\image html double_faces.png
+
+In this picture some faces are coincident after copying all elements
+with translation with subsequent Merge of nodes.
+
+\sa A sample TUI Script of a \ref filter_double_elements "Filters of Double Elements".
+
+*/
--- /dev/null
+/*!
+
+\page double_nodes_control_page Double nodes
+
+This mesh quality control highlights the nodes which are coincident with other nodes (within a given tolerance).
+
+\image html double_nodes.png
+
+In this picture some nodes are coincident after copying all elements with translation.
+
+\sa A sample TUI Script of a \ref tui_double_nodes_control "Double Nodes" filter.
+
+*/
</li>
</ul>
+Additional criteria to select mesh <b>Nodes</b> are the following:
+<ul><li>
+<b>Free nodes</b> selects nodes belonging to none mesh element.
+</li><li>
+<b>Double nodes</b> selects node coincident with other nodes
+(within a given <b>Tolerance</b>).
+See also \ref tui_double_nodes_control "Double Nodes quality control".
+</li>
+</ul>
+
Additional criteria to select mesh <b>Edges</b> are the following:
<ul><li>
<b>Free Borders</b> selects free 1D mesh elements, i.e. edges belonging to
one face only. See also a
\ref free_borders_page "Free Borders quality control".
</li><li>
+<b>Double edges</b> selects 1D mesh elements basing on the same set of nodes.
+See also \ref filter_double_elements "Double Elements quality control".
+</li><li>
<b>Borders at Multi-Connections</b> selects edges belonging to several faces.
The number of faces should be more, less or equal (within a given <b>Tolerance</b>)
to the predefined <b>Threshold Value</b>. See also a
</li><li>
<b>Free faces</b> selects 2D mesh elements wich belong to less than two volumes.
</li><li>
+<b>Double faces</b> selects 2D mesh elements basing on the same set of nodes.
+See also \ref filter_double_elements "Double Elements quality control".
+</li><li>
<b>Faces with bare border</b> selects 2D mesh elements having a free border without an edge on it.
See also \ref bare_border_faces_page "Bare border faces quality control".
</li><li>
(within a given <b>Tolerance</b>) to the predefined <b>Threshold Value</b>. See also a
\ref max_element_length_3d_page "Element Diameter 3D quality control".
</li><li>
+<b>Double volumes</b> selects 3D mesh elements basing on the same set of nodes.
+See also \ref filter_double_elements "Double Elements quality control".
+</li><li>
<b>Bad oriented volume</b> selects mesh volumes, which are incorrectly oriented from
the point of view of MED convention.
</li><li>
\sa \ref tui_over_constrained_faces
+\section filter_double_elements Double edges, Double faces, Double volumes
+
+filter mesh elements basing on the same set of nodes:
+- element type is either \a smesh.EGDE, \a smesh.FACE or \a smesh.VOLUME
+- functor type is either \a smesh.FT_EqualEdges, \a
+ smesh.FT_EqualFaces or \a smesh.FT_EqualVolumes,
+- threshold value is not required
+
+\code
+from smesh import *
+# make a mesh on a box
+box = geompy.MakeBoxDXDYDZ(100,100,100)
+mesh = Mesh( box, "Box" )
+mesh.Segment().NumberOfSegments(10)
+mesh.Quadrangle()
+mesh.Hexahedron()
+mesh.Compute()
+# copy all elements with translation and Merge nodes
+mesh.TranslateObject( mesh, MakeDirStruct( 10,0,0), Copy=True )
+mesh.MergeNodes( mesh.FindCoincidentNodes(1e-7) )
+# create filters to find equal elements
+equalEdgesFilter = GetFilter(SMESH.EDGE, FT_EqualEdges)
+equalFacesFilter = GetFilter(SMESH.FACE, FT_EqualFaces)
+equalVolumesFilter = GetFilter(SMESH.VOLUME, FT_EqualVolumes)
+# get equal elements
+print "Number of equal edges:", len( mesh.GetIdsFromFilter( equalEdgesFilter ))
+print "Number of equal faces:", len( mesh.GetIdsFromFilter( equalFacesFilter ))
+print "Number of equal volumes:", len( mesh.GetIdsFromFilter( equalVolumesFilter ))
+\endcode
+
+
+\section tui_double_nodes_control Double nodes
+
+filters mesh nodes which are coincident with other nodes (within a given tolerance):
+- element type is \a smesh.NODE
+- functor type is \a smesh.FT_EqualNodes
+- threshold value is not required
+- default tolerance is 1.0e-7
+
+\code
+from smesh import *
+# make a mesh on a box
+box = geompy.MakeBoxDXDYDZ(100,100,100)
+mesh = Mesh( box, "Box" )
+mesh.Segment().NumberOfSegments(10)
+mesh.Quadrangle()
+mesh.Hexahedron()
+mesh.Compute()
+# copy all elements with translation
+mesh.TranslateObject( mesh, MakeDirStruct( 10,0,0), Copy=True )
+# create filters to find nodes equal within tolerance of 1e-5
+filter = GetFilter(SMESH.NODE, FT_EqualNodes, Tolerance=1e-5)
+# get equal nodes
+print "Number of equal nodes:", len( mesh.GetIdsFromFilter( filter ))
+\endcode
+
+
\section filter_borders_multiconnection Borders at multi-connection
Filter border 1D mesh elements (edges) according to the specified number of
