\page selection_filter_library_page Selection filter library
+\tableofcontents
+
+\section selection_filter_library Filter library
+
\n Selection filter library allows creating and storing in files
-filters that can be later reused for operations on meshes. You can
-access to it from the Main Menu via <b>Tools / Selection filter library</b>.
-It is also possible to save any filter by invoking the filter library
-from \a Filter dialog launched from any mesh operation.
+the filters that can be later reused for operations on meshes. You can
+access it from the Main Menu via <b>Tools / Selection filter library</b>.
+It is also possible to save/load a filter by invoking the filter library
+from \ref filtering_elements "Filter dialog" launched from any mesh operation.
\image html selectionfilterlibrary.png
\n In <b>Filter name</b> box you can specify the name for your
filter. By default it is prefixed with the corresponding entity type.
-\anchor filtering_elements
+\section filtering_elements Filter Dialog
-When we use filters during a group creation or another operation (by
+When we use filters during group creation or another operation (by
clicking <b>Set Filter</b> button in the corresponding dialog), the
dialog for setting filters looks as shown below.
The \b Add button creates a new criterion at the end of the list of
criteria. The \b Insert button creates a new criterion before the
selected criterion. The \b Remove button deletes the selected
-criterion. The \b Clear button deletes all criteria.
+criterion. The \b Clear button deletes all criteria.\n
+If there is a choice of <b>Entity type</b> in the dialog, only
+criteria of currently selected type are used to create or change a
+filter, and criteria of hidden types (if were specified) are ignored.
\n Each <b>Entity type</b> has its specific list of criteria, however all
filters have common syntax. The <b>Threshold Value</b> should be specified
for most criteria. For numerical criteria it is necessary to indicate if
is no selected mesh in the Object Browser and the filter can not be
created. You have to select the mesh and the button will be enabled.
+\section filtering_criteria Filtering Criteria
+
Some criteria are applicable to all <b>Entity types</b>:
<ul><li>
<b>Belong to Geom</b> selects entities whose all nodes lie on the
-shape defined by <b>Threshold Value</b>. If the threshold shape is a
-sub-shape of the main shape of the mesh the algorithm works faster, if
-this is any other shape the algorithm works slower.
+shape defined by <b>Threshold Value</b>.
+If the threshold shape is a sub-shape of the main shape of the mesh,
+the filtering algorithm works faster because node-to-shape association
+is used instead of measuring distance between nodes and the shape, and
+\b Tolerance is not used. If the threshold shape is any other shape,
+the algorithm works slower because distance between nodes and the
+shape is measured and is compared with \b Tolerance. The latter
+approach (distance measurement) is also used if an element is not
+associated to any shape.
</li><li>
<b>Lying on Geom</b> selects entities whose at least one node
lies on the shape defined by the <b>Threshold Value</b>.
-If the threshold shape is a sub-shape of the main shape of the mesh the
-algorithm works faster, if this is any other
-shape, the algorithm works slower.
+If the threshold shape is a sub-shape of the main shape of the mesh,
+the filtering algorithm works faster because node-to-shape association
+is used instead of measuring distance between nodes and the shape, and
+\b Tolerance is not used. If the threshold shape is any other shape,
+the algorithm works slower because distance between nodes and the
+shape is measured and is compared with \b Tolerance. The latter
+approach (distance measurement) is also used if an element is not
+associated to any shape.
</li><li>
<b>Belong to Mesh Group</b> selects entities included into the mesh group
defined by the <b>Threshold Value</b>.
</li>
</ul>
-Some criteria are applicable to all <b>Entity types</b> of dimension
+Some criteria are applicable to entities of dimension
more than zero, i.e. to \b Edges, \b Faces and \b Volumes:
<ul><li>
<b>Linear</b> allows selection of Linear or Quadratic elements (if Unary is set to "Not")
</li>
</ul>
-The following criteria are applicable to all <b>Entity types</b>
-except for <b>Volumes</b>:
+The following criteria are applicable to Entities of \b all types
+except for \a Volumes:
<ul><li>
<b>Belong to Plane</b> selects entities whose all nodes belong to a
specified plane within a given <b>Tolerance</b>.
<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><li>
+<b>Connectivity number</b> selects nodes with a number of connected
+elements, which is more, less or equal to the predefined <b>Threshold
+ Value</b>. Elements of the highest dimension are countered only.
</li>
</ul>
\ref area_page "Area quality control"), which is more, less or equal (within a given
<b>Tolerance</b>) to the predefined <b>Threshold Value</b>.
</li><li>
-<b>Free edges</b> selects 2D mesh elements having at least one of its
-edges not shared with other faces. See also a
+<b>Free edges</b> selects 2D mesh elements having at least one
+edge, which is not shared with other faces. See also a
\ref free_edges_page "Free Edges quality control".
</li><li>
<b>Free faces</b> selects 2D mesh elements, which belong to less than two volumes.
angular tolerance (defined in degrees). Selection continues among all neighbor faces of already
selected ones.<br>
</li><li>
+<b>Deflection 2D</b> selects 2D mesh elements having distance between their gravity
+centers and underlying surfaces, which is more, less or equal (within a given <b>Tolerance</b>) to the predefined <b>Threshold Value</b>. See also a
+\ref deflection_2d_page "Deflection 2D quality control".
+</li><li>
<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
</li>
</ul>
-The following criteria allow selecting mesh <b>Volumes</b>:
+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
