-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>.