0022107: EDF 2502 SMESH: Publish the result of show bad mesh in a group

[modules/smesh.git] / doc / salome / gui / SMESH / input / prism_3d_algo.doc

diff --git a/doc/salome/gui/SMESH/input/prism_3d_algo.doc b/doc/salome/gui/SMESH/input/prism_3d_algo.doc
index 5589ba3a761c8199ea4716deab69ce9cacb9ad88..d377b549fba48f3514c584d8c461a661ece47d78 100644 (file)
--- a/doc/salome/gui/SMESH/input/prism_3d_algo.doc
+++ b/doc/salome/gui/SMESH/input/prism_3d_algo.doc
@@ -2,23 +2,70 @@
 
 \page prism_3d_algo_page 3D extrusion meshing algorithm
 
 
 \page prism_3d_algo_page 3D extrusion meshing algorithm
 

-3D extrusion algorithm can be used for meshing prisms, i.e. <b>3D Shapes</b>
+3D extrusion algorithm can be used for meshing prisms, i.e. 3D shapes

 defined by two opposing faces having the same number of vertices and
 defined by two opposing faces having the same number of vertices and

-edges and meshed using, for example,  the \ref projection_algos_page
-"2D Projection" algorithm. These two faces should be connected by
-quadrangle "side" faces.
+edges. These two faces should be connected by quadrangle "side" faces.

 
 

-The opposing faces can be meshed with either quadrangles or triangles,
-while the side faces should be meshed with quadrangles only.
+The prism is allowed to have sides composed of several faces. (A prism
+side is a row of faces (or one face) connecting the corresponding edges of
+the top and base faces). However, a prism 
+side can be split only vertically as indicated in the
+picture below. 

 
 

-\image html image157.gif "Prism with 3D extrusion meshing".
+\image html prism_ok_ko.png "A suitable and an unsuitable prism"
+In this picture, the left prism is suitable for meshing with 3D
+extrusion algorithm: it has six sides, two of which are split
+vertically. The right prism cannot be meshed with this
+algorithm because one of the prism sides is split horizontally (the
+splitting edge is highlighted).

 
 

-As you can see, the <b>3D extrusion</b> algorithm permits to build and to
-have in the same 3D mesh such elements as hexahedrons, prisms and
-polyhedrons.
+The algorithm can propagate 2D mesh not only between horizontal
+(i.e. base and top) faces of one prism but also between faces of prisms
+organized in a stack and between stacks sharing prism sides.

 
 

-\note This algorithm works correctly only if the opposing faces have
-the same (or similar) meshing topography. Otherwise, 3D extrusion
-algorithm can fail to build mesh volumes.
+\image html prism_stack.png "Prism stacks"
+This picture shows four neighboring prism stacks, each comprising two prisms.
+The shown sub-mesh is used by the algorithm to mesh
+all eight prisms in the stacks.
+
+To use <em>3D extrusion</em> algorithm you need to assign algorithms
+and hypotheses of lower dimensions as follows.
+(A sample picture below shows algorithms and hypotheses used to
+mesh a cylinder with prismatic volumes).
+
+\image html prism_needs_hyps.png 
+
+The \b Global algorithms and hypotheses to be chosen at 
+\ref create_mesh_anchor "Creation of a mesh object" are:
+<ul>
+<li> 1D algorithm and hypothesis that will be applied for meshing
+  (logically) vertical edges of the prism (which connect the top and the
+  base faces of the prism). In the sample picture above these are
+  "Regular_1D" algorithm and "Nb. Segments_1" hypothesis.</li>
+</ul>
+
+The \b Local algorithms and hypotheses to be chosen at 
+\ref constructing_submeshes_page "Construction of sub-meshes" are:
+<ul>
+  <li> 1D and 2D algorithms and hypotheses that will be applied for
+    meshing the top and the base prism faces. These faces can be meshed
+    with any type of 2D elements: quadrangles, triangles, polygons or
+    their mix. It is enough to define a sub-mesh on either the top or the base
+    face. In the sample picture above, "BLSURF" algorithm meshes
+    "Face_1" base surface with triangles. (1D algorithm is not
+    assigned as "BLSURF" does not require divided edges to create a 2D mesh.)
+  </li>
+  <li> Optionally you can define a 1D sub-mesh on some vertical edges
+    of stacked prisms, which will override the global 1D hypothesis mentioned
+    above. In the <b>Prism stacks</b> picture, the
+    vertical division is not equidistant on the whole length because 
+    a "Number Of Segments" hypothesis with Scale Factor=3 is assigned to
+    the highlighted edge. 
+</li></ul>
+
+\image html image157.gif "Prism with 3D extrusion meshing. Vertical division is different on neighbor edges because several local 1D hypotheses are assigned."
+
+\sa a sample TUI Script of
+\ref tui_prism_3d_algo "Use 3D extrusion meshing algorithm".

 
 */
 
 */