0021893: EDF 2133 SMESH : Improvement of 3D extrusion algorithm

doc/salome/gui/SMESH/input/prism_3d_algo.doc

@@ -30,35 +30,43 @@ all the eight prisms in the stacks.
 
 To use <em>3D extrusion</em> algorithm you need to assign algorithms
 and hypotheses of lower dimension as follows.
+(A sample picture below shows algorithms and hypotheses used to
+mesh a cylinder with prismatic volumes).
+
+\image html prism_needs_hyps.png
 
 \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 (these edges connect the top and
-base faces of prism).</li>
+  (logically) vertical edges of the prism (these edges connect the top and
+  base faces of prism). In the sample picture above these are
+  "Regular_1D" algorithm and "Nb. Segments_1" hypothesis.</li>
 </ul>
 
 \b Local algorithms and hypotheses to be chosen at 
 \ref constructing_submeshes_page "Constructing sub-meshes" are:
 <ul>
-<li> 1D and 2D algorithms and hypotheses that will be applied for
-meshing the top and base prism faces. These faces can be meshed
-with any type of 2D elements: quadrangles, triangles, polygons or
-their mix. It's enough to define a sub-mesh on either top or base face
-only.</li>
-<li> Optionally you can define an 1D sub-mesh on some vertical edges
-of stacked prisms, which will override the global 1D hypothesis mentioned
-above. In the above picture, the vertical division is not equidistant
-on all the length because of a "Number Of Segments" hypothesis with
-Scale Factor=3 assigned to one of edges between the shifted stacks. 
+  <li> 1D and 2D algorithms and hypotheses that will be applied for
+    meshing the top and base prism faces. These faces can be meshed
+    with any type of 2D elements: quadrangles, triangles, polygons or
+    their mix. It's enough to define a sub-mesh on either top or 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 2D mesh.)
+  </li>
+  <li> Optionally you can define an 1D sub-mesh on some vertical edges
+    of stacked prisms, which will override the global 1D hypothesis mentioned
+    above. In the picture above the picture of Object Browser, the
+    vertical division is not equidistant on all the length because of
+    a "Number Of Segments" hypothesis with Scale Factor=3 assigned to
+    the highlighted edge. 
 </li></ul>
 
-\image html image157.gif "Prism with 3D extrusion meshing"
+\image html image157.gif 
 
-As you can see, the <em>3D extrusion</em> algorithm permits to build
-in the same 3D mesh such elements as hexahedrons, prisms and
-polyhedrons.
+Prism with 3D extrusion meshing. "Vertical" division is different on
+neighbor edges due to local 1D hypotheses assigned.
 
 \sa a sample TUI Script of
 \ref tui_prism_3d_algo "Use 3D extrusion meshing algorithm".

doc/salome/gui/SMESH/input/tui_prism_3d_algo.doc

@@ -54,25 +54,30 @@ bigQuad   = geompy.GetFaceNearPoint( prisms, geompy.MakeVertex( 15,15,0 ), "bigQ
 
 mesh = smesh.Mesh( prisms )
 
-# vertical division
+# assign Global hypotheses
+
+# 1D algorithm and hypothesis for vertical division
 mesh.Segment().NumberOfSegments(15)
 
 # Extrusion 3D algo
 mesh.Prism()
 
-# mesh smallQuad with quadrilaterals
+# assign Local hypotheses
+
+# 1D and 2D algos and hyps to mesh smallQuad with quadrilaterals
 mesh.Segment(smallQuad).LocalLength( 3 )
 mesh.Quadrangle(smallQuad)
 
-# mesh bigQuad with triangles
+# 1D and 2D algos and hyps to mesh bigQuad with triangles
 mesh.Segment(bigQuad).LocalLength( 3 )
 mesh.Triangle(bigQuad)
 
+# compute the mesh
 mesh.Compute()
 
 \endcode
 
-The result mesh is shown below
+The result geometry and mesh is shown below
 \image html prism_tui_sample.png
 
 */