smesh/doc/salome/gui/SMESH/input/basic_meshing_algos.doc

/*!

\page basic_meshing_algos_page Basic meshing algorithms

\n The MESH module contains a set of meshing algorithms, which are
used for meshing entities (1D, 2D, 3D sub-shapes) composing
geometrical objects.

An algorithm represents either an implementation of a certain meshing
technique or an interface to the whole meshing program generating elements
of several dimensions.

<ul>
<li>For meshing of 1D entities (<b>edges</b>):</li>
\anchor a1d_algos_anchor
<ul>
<li><em>Wire Discretization</em> meshing algorithm - splits an edge into a
number of mesh segments following an 1D hypothesis.
</li>
<li><em>Composite Side Discretization</em> algorithm - allows to apply a 1D
  hypothesis to a whole side of a geometrical face even if it is
  composed of several edges provided that they form C1 curve in all
  faces of the main shape.</li>
</ul>

<li>For meshing of 2D entities (<b>faces</b>):</li>

<ul>
<li><em>Triangle (Mefisto)</em> meshing algorithm - splits faces
  into triangular elements.</li>
<li>\subpage quad_ijk_algo_page "Quadrangle (Mapping)" meshing
  algorithm - splits faces into quadrangular elements.</li>
</ul>

\image html image123.gif "Example of a triangular 2D mesh"

\image html image124.gif "Example of a quadrangular 2D mesh"

<li>For meshing of 3D entities (<b>solid objects</b>):</li>

<ul>
<li><em>Hexahedron (i,j,k)</em> meshing algorithm - solids are
  split into hexahedral elements thus forming a structured 3D
  mesh. The algorithm requires that 2D mesh generated on a solid could
  be considered as a mesh of a box, i.e. there should be six nodes shared
  by three quadrangles and the rest nodes should be shared by four
  quadrangles.
\image html hexa_ijk_mesh.png "Structured mesh generated by Hexahedron (i,j,k) on a solid bound by 16 faces"
</li>

<li>\subpage cartesian_algo_page "Body Fitting" meshing
  algorithm - solids are split into hexahedral elements forming
  a Cartesian grid; polyhedra and other types of elements are generated
  where the geometrical boundary intersects Cartesian cells.</li>
</ul>

\image html image125.gif "Example of a tetrahedral 3D mesh"

\image html image126.gif "Example of a hexahedral 3D mesh"
</ul>

Some 3D meshing algorithms, such as Hexahedron(i,j,k) and some
commercial ones, also can generate 3D meshes from 2D meshes, working
without geometrical objects.

There is also a number of more specific algorithms:
<ul>
<li>\subpage prism_3d_algo_page "for meshing prismatic 3D shapes"</li>
<li>\subpage quad_from_ma_algo_page "for meshing faces with sinuous borders"</li>
<li> <em>Polygon per Face</em> meshing algorithm - generates one mesh
  face (either a triangle, a quadrangle or a polygon) per a geometrical
  face using all nodes from the face boundary.</li>
<li>\subpage projection_algos_page "for meshing by projection of another mesh"</li>
<li>\subpage import_algos_page "for meshing by importing elements from another mesh"</li>
<li>\subpage radial_prism_algo_page "for meshing geometrical objects with cavities"</li>
<li>\subpage radial_quadrangle_1D2D_algo_page "for meshing special faces (circles and parts of circles)"</li>
<li>\subpage use_existing_page "Use Edges to be Created Manually" and 
\ref use_existing_page "Use Faces to be Created Manually" algorithms can be
used to create a 1D or a 2D mesh in a python script.</li>
<li>\subpage segments_around_vertex_algo_page "for defining the local size of elements around a certain node"</li>
</ul>

\ref constructing_meshes_page "Constructing meshes" page describes in
detail how to apply meshing algorithms.

<br><b>See Also</b> a sample TUI Script of a 
\ref tui_defining_meshing_algos "Define Meshing Algorithm" operation.  

*/