It allows Quadrangle (Mapping) to build quadrangular meshes even if the number
of nodes at the opposite edges of a meshed face is not equal,
-otherwise this mesh will contain some triangular elements.
+otherwise this mesh will contain some triangular elements. <i>This use
+case is obsolete now. Use <b>Quadrangle Parameters</b> hypothesis with
+type <b>Quadrangle Preference</b> set instead.</i>
<br>
This hypothesis has one restriction on its work: the total quantity of
segments on all four sides of the face must be even (divisible by 2).
-<h2>Triangle Preference</h2>
+<h2>Triangle Preference <i>(obsolete)</i></h2>
This additional hypothesis can be used only together with Quadrangle (Mapping)
algorithm. It allows to build triangular mesh faces in the refinement
area if the number of nodes at the opposite edges of a meshed face is not equal,
otherwise refinement area will contain some quadrangular elements.
-
+<i>This hypothesis is obsolete now. Use <b>Quadrangle Parameters</b>
+hypothesis with type <b>Triangle Preference</b> set instead.</i>
+
+\anchor viscous_layers_anchor
+<h2>Viscous Layers</h2>
+
+<b>Viscous Layers</b> additional hypotheses can be used together with
+several 3D algorithms: NETGEN 3D, GHS3D and Hexahedron(i,j,k). This
+hypothesis allows creation of layers of highly stretched prisms near
+mesh boundary, which is beneficial for high quality viscous
+computations. The prisms constructed on the quadrangular mesh faces are
+actually the hexahedrons.
+
+
+\image html viscous_layers_hyp.png
+
+<ul>
+<li><b>Name</b> - allows to define the name of the hypothesis.</li>
+<li><b>Total thicknes</b> - gives total thickness of layers of prisms.</li>
+<li><b>Number of layers</b> - defines number of layers of prisms.</li>
+<li><b>Stretch factor</b> - defines factor of growth of height of
+prisms from the mesh boundary towards inside of mesh.</li>
+<li><b>Faces without layers</b> - defines geometrical faces on which
+layers of prisms should not be constructed. By default the layers of
+prisms are not constructed on geometrical faces shared by solids.</li>
+</ul>
+
+\image html viscous_layers_mesh.png A group containing viscous layer prisms.
+
+<br><b>See also</b> a sample TUI script of a \ref tui_viscous_layers
+"Viscous layers construction".
+
*/
