</li>
</ul>
-Additional criteria to select mesh <b>Edges</b> are the following:
+The following criteria allow selecting mesh <b>Nodes</b>:
+<ul><li>
+<b>Free nodes</b> selects nodes not belonging to any mesh element.
+</li><li>
+<b>Double nodes</b> selects a node coincident with other nodes
+(within a given <b>Tolerance</b>).
+See also \ref tui_double_nodes_control "Double Nodes quality control".
+</li>
+</ul>
+
+The following criteria allow selecting mesh <b>Edges</b>:
<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>
</ul>
-Additional criteria to select mesh <b>Faces</b> are the following:
+The following criteria allow selecting mesh <b>Faces</b>:
<ul><li>
<b>Aspect ratio</b> selects 2D mesh elements with an aspect ratio (see also an
\ref aspect_ratio_page "Aspect Ratio quality control"), which is more, less or equal
</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>
angular tolerance (defined in degrees). Selection continues among all neighbor faces of already
selected ones.<br>
</li><li>
-<b>Element Diameter 2D</b> selects triangles and quadrangles combining of the edges and
+<b>Element Diameter 2D</b> selects triangles and quadrangles composed of the edges and
diagonals with a value of length, which is more, less or equal
(within a given <b>Tolerance</b>) to the predefined <b>Threshold Value</b>. See also a
\ref max_element_length_2d_page "Element Diameter 2D quality control".
</li>
</ul>
-Additional criteria to select mesh <b>Volumes</b> are the following:
+The following criteria allow selecting mesh <b>Volumes</b>:
<ul><li>
<b>Aspect ratio 3D</b> selects 3D mesh elements with an aspect ratio (see also an
\ref aspect_ratio_3d_page "Aspect Ratio 3D quality control"), which is more, less or equal
\ref volume_page "Volume quality control"), which is more, less or equal (within a given
<b>Tolerance</b>) to the predefined <b>Threshold Value</b>.
</li><li>
-<b>Element Diameter 3D</b> selects 3D mesh elements combining of the edges and
+<b>Element Diameter 3D</b> selects 3D mesh elements composed of the edges and
diagonals with a value of length, which is more, less or equal
(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>