X-Git-Url: http://git.salome-platform.org/gitweb/?p=modules%2Fsmesh.git;a=blobdiff_plain;f=doc%2Fsalome%2Fgui%2FSMESH%2Finput%2F2d_meshing_hypo.doc;h=234ffd11b51fa1958685f97e9b05c65e4df7a8fd;hp=c5095b1bff90c30808e0738feedceedef6fb0964;hb=2a6e16b7faacf40cf3b91605690ce04f14141f1b;hpb=f0faaf2c4f45703ffeb686b0e5f1af2783ba74f1

diff --git a/doc/salome/gui/SMESH/input/2d_meshing_hypo.doc b/doc/salome/gui/SMESH/input/2d_meshing_hypo.doc
index c5095b1bf..234ffd11b 100644
--- a/doc/salome/gui/SMESH/input/2d_meshing_hypo.doc
+++ b/doc/salome/gui/SMESH/input/2d_meshing_hypo.doc
@@ -2,20 +2,16 @@
 
 \page a2d_meshing_hypo_page 2D Meshing Hypotheses
 
-<br>
-<ul>
-<li>\ref max_element_area_anchor "Max Element Area"</li>
-<li>\ref length_from_edges_anchor "Length from Edges"</li>
-<li>\ref hypo_quad_params_anchor "Quadrangle parameters"</li>
-</ul>
+- \ref max_element_area_anchor "Max Element Area"
+- \ref length_from_edges_anchor "Length from Edges"
+- \ref hypo_quad_params_anchor "Quadrangle parameters"
 
-<br>
 \anchor max_element_area_anchor
 <h2>Max Element Area</h2>
 
 <b>Max Element Area</b> hypothesis is applied for meshing of faces
 composing your geometrical object. Definition of this hypothesis
-consists of setting the <b>maximum area</b> of mesh elements,
+consists of setting the <b>maximum area</b> of mesh faces,
 which will compose the mesh of these faces.
 
 \image html a-maxelarea.png
@@ -25,32 +21,66 @@ which will compose the mesh of these faces.
 \image html max_el_area.png "In this example, Max. element area is very small compared to the 1D hypothesis"
 
 <b>See Also</b> a sample TUI Script of a 
-\ref tui_max_element_area "Maximum Element Area" hypothesis
-operation. 
+\ref tui_max_element_area "Maximum Element Area" hypothesis operation. 
 
-<br>
 \anchor length_from_edges_anchor
 <h2>Length from Edges</h2>
 
-<b>Length from edges</b> hypothesis builds 2D mesh elements having a
-maximum linear size calculated as an average segment length for a wire
-of a given face.
+<b>Length from edges</b> hypothesis defines maximum linear size of
+mesh faces as an average length of mesh edges approximating a boundary
+of a face being meshed.
 
 <b>See Also</b> a sample TUI Script of a 
 \ref tui_length_from_edges "Length from Edges" hypothesis operation.
 
-<br>
 \anchor hypo_quad_params_anchor
 <h2>Quadrangle parameters</h2>
 
-\image html hypo_quad_params_dialog.png "Quadrangle parameters creation/edition dialog"
+\image html hypo_quad_params_dialog.png "Quadrangle parameters: Transition"
+
+<b>Quadrangle parameters</b> is a hypothesis for Quadrangle (Mapping) algorithm.
+
+<b>Transition</b> tab is used to define the algorithm of transition
+between opposite sides of the face with a different number of
+segments on them. The following types of transition
+algorithms are available:
+
+- <b>Standard</b> is the default case, when both triangles and quadrangles
+  are possible in the transition area along the finer meshed sides.
+- <b>Triangle preference</b> forces building only triangles in the
+  transition area along the finer meshed sides.
+  \note This type corresponds to <b>Triangle Preference</b> additional hypothesis,
+  which is obsolete now.
+- <b>Quadrangle preference</b> forces building only quadrangles in the
+  transition area along the finer meshed sides. This hypothesis has a
+  restriction: the total quantity of segments on all
+  four face sides must be even (divisible by 2).
+  \note This type corresponds to <b>Quadrangle Preference</b> additional hypothesis,
+  which is obsolete now.
+- <b>Quadrangle preference (reversed)</b> works in the same way and
+  with the same restriction as <b>Quadrangle preference</b>, but
+  the transition area is located along the coarser meshed sides.
+- <b>Reduced</b> type forces building only quadrangles and the transition
+  between the sides is made gradually, layer by layer. This type has
+  a limitation on the number of segments: one pair of opposite sides must have
+  the same number of segments, the other pair must have an even total
+  number of segments. In addition, the number of rows
+  between sides with different discretization
+  should be enough for the transition. Following the fastest transition
+  pattern, three segments become one (see the image below), hence
+  the least number of face rows needed to reduce from Nmax segments
+  to Nmin segments is log<sub>3</sub>( Nmax / Nmin ). The number of
+  face rows is equal to the number of segments on each of equally
+  discretized sides.
 
-<b>Quadrangle parameters</b> is a hypothesis for Quadrangle (Mapping).
+\image html reduce_three_to_one.png "The fastest transition pattern: 3 to 1"
 
-<b>Base vertex</b> parameter allows using Quadrangle (Mapping)
+<b>Base vertex</b> tab allows using Quadrangle (Mapping)
 algorithm for meshing of trilateral faces. In this case it is
-necessary to select the vertex, which will be used as the fourth edge
-(degenerated).
+necessary to select the vertex, which will be used as the forth
+degenerated side of quadrangle.
+
+\image html hypo_quad_params_dialog_vert.png "Quadrangle parameters: Base Vertex"
 
 \image html hypo_quad_params_1.png "A face built from 3 edges"
 
@@ -68,41 +98,46 @@ shows the good (left) and the bad (right) results of meshing.
 
 \image html hypo_quad_params_res_2.png "The resulting meshes"
 
-<b>Type</b> parameter is used on faces with a different number of
-segments on opposite sides to define the algorithm of transition
-between them. The following types are available:
+\image html hypo_quad_params_dialog_enf.png "Quadrangle parameters: Enforced nodes"
 
+<b>Enforced nodes</b> tab allows defining points, where the
+algorithm should create nodes. There are two ways to define positions
+of the enforced nodes.
 <ul>
-<li><b>Standard</b> is the default case, when both triangles and quadrangles
-    are possible in the transition area along the finer meshed sides.</li>
-<li><b>Triangle preference</b> forces building only triangles in the
-    transition area along the finer meshed sides.
-    <i>This type corresponds to <b>Triangle Preference</b> additional
-    hypothesis, which is obsolete now.</i></li>
-<li><b>Quadrangle preference</b> forces building only quadrangles in the
-    transition area along the finer meshed sides. This hypothesis has a
-    restriction: the total quantity of segments on all
-    four sides of the face must be even (divisible by 2).</li>
-    <i>This type corresponds to <b>Quadrangle Preference</b>
-    additional hypothesis, which is obsolete now.</i></li>
-<li><b>Quadrangle preference (reversed)</b> works in the same way and
-  with the same restriction as <b>Quadrangle preference</b>, but
-  the transition area is located along the coarser meshed sides.</li>
-<li><b>Reduced</b> type forces building only quadrangles and the transition
-    between the sides is made gradually, layer by layer. This type has
-    a limitation on the number of segments: one pair of opposite sides must have
-    the same number of segments, the other pair must have an even difference
-    between the numbers of segments on the sides. In addition, number
-    of rows of faces between sides with different discretization
-    should be enough for the transition. At the fastest transition
-    pattern, three segments become one (see the image below), hence
-    the least number of face rows needed to reduce from Nmax segments
-    to Nmin segments is log<sub>3</sub>( Nmax / Nmin ). The number of
-    face rows is equal to number of segments on each of equally
-    discretized sides.
-\image html reduce_three_to_one.png "The fastest transition pattern: 3 to 1"
-</li>
+  <li>\b Vertices group allows to set up shapes whose vertices will
+    define positions of the enforced nodes. Only vertices successfully
+    projected to the meshed face and located close enough to the
+    meshed face will be used to create the enforced nodes.</li>
+  <li> \b Points group allows to explicitly define coordinates of
+    points used to create the enforced nodes. Only points successfully
+    projected to the meshed face and located close enough to the
+    meshed face will be used to create the enforced nodes.</li>
+</ul>
+\note <b>Enforced nodes</b> can't be created at \b Reduced transition type.
+
+Let us see how the algorithm works:
+<ul>
+  <li> Initially positions of nodes are computed without taking into
+  account the enforced vertex (yellow point).</li> 
+\image html hypo_quad_params_enfnodes_algo1.png "Initial mesh"
+
+  <li> Then the node closest to the enforced vertex is
+    detected. Extreme nodes of the row and column of the detected node
+    are used to create virtual edges (yellow lines) ending at the
+    enforced vertex. </li>
+\image html hypo_quad_params_enfnodes_algo2.png "Creation of virtual edges"
+	
+  <li> Consequently, the meshed face is divided by the virtual
+    edges into four quadrilateral sub-domains each of which is meshed
+    as usually: the nodes of the row and column of the detected node are
+    moved to the virtual edges and the quadrilateral elements are
+    constructed. 
+	
+\image html hypo_quad_params_enfnodes_algo3.png "Final mesh"	
+
 </ul>
+If there are several enforced vertices, the algorithm is applied
+recursively to the formed sub-domains.
 
 <b>See Also</b> a sample TUI Script of a 
 \ref tui_quadrangle_parameters "Quadrangle Parameters" hypothesis.