\page selection_filter_library_page Selection filter library
-\n Selection filter library is a powerful tool enabling to create
-filters to be used on meshes. You can access to it from the Main Menu
-via <b>Tools / Selection filter library</b>.
+\n Selection filter library allows creating and storing in files
+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
filter. By default it is prefixed with the corresponding entity type.
\anchor filtering_elements
+<h2>Filter Dialog</h2>
-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
-menu for setting filters looks as shown below.
+dialog for setting filters looks as shown below.
+
+\image html a-filteronfaces.png
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. For each criterion you should specify the
-<b>Threshold Value</b> and for numerical criteria whether we search
-for the elements that should be \b More, \b Less or \b Equal to this
+filters have common syntax. The <b>Threshold Value</b> should be specified
+for most criteria. For numerical criteria it is necessary to indicate if
+the found elements should be \b More, \b Less or \b Equal to this
\b Value. You can also reverse the sense of a criterion using \b Unary
operator \a Not and you should specify logical relations between
criteria using \b Binary operators \a Or and \a And.
\n Some criteria have the additional parameter of \b Tolerance.<br>
-Switching on <b>Insert filter in viewer</b> checkbox limits
+Switching on <b>Insert filter in viewer</b> check-box limits
selection of elements in the Viewer to the current filter.
<br>
In the \b Source field you choose if the filter will be applied to
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.
-\image html a-filteronfaces.png
-
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 <b>Threshold Value</b>.
+defined by the <b>Threshold Value</b>.
</li><li>
<b>Range of IDs</b> allows selection of entities with the specified
IDs.
</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")
types depends on the current entity type.
</li><li>
<b>Entity type</b> allows selection of elements by their type defined
-as combination of geometry type + number of nodes.
+as a combination of geometry type and the number of nodes.
</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>.
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
+one element (face or volume) 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.
\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 consisting of edges belonging to
-one element of mesh only. 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.
</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
