\page about_meshes_page About meshes
\n \b MESH represents a discrete approximation of a subset of the
-three-dimensional space by \ref mesh_entities "elementary geometrical elements".
+three-dimensional space by \ref mesh_entities "elementary geometrical
+elements".
+
+A SALOME study can contain multiple meshes, but they do not
+implicitly compose one super-mesh, and finally each of them
+can be used (e.g. exported) only individually.
Mesh module provides several ways to create the mesh:
<ul>
<li>The main way is to \subpage constructing_meshes_page "construct the mesh"
on the basis of the geometrical shape produced in the Geometry
module. This way implies selection of
- - a geometrical object (<em> main shape</em>) and
+ - a geometrical object (<em>main shape</em>) and
- <em>meshing parameters</em> (\ref
basic_meshing_algos_page "meshing algorithms" and
characteristics (e.g. element size) of a
Construction of \subpage constructing_submeshes_page "sub-meshes"
allows to discretize some sub-shapes of the main shape, for example a face,
- using different meshing parameters than other sub-shapes.<br>
+ using the meshing parameters that differ from those used for other sub-shapes.<br>
Meshing parameters of meshes and sub-meshes can be
\subpage editing_meshes_page "edited". (Upon edition only mesh entities
generated using changed meshing parameters are removed and will be
re-computed).<br>
- \note Algorithms and hypotheses used at mesh level are referred as
- \a global ones and those used at sub-mesh level are referred as \a
+ \note Algorithms and hypotheses used at mesh level are referred to as
+ \a global ones and those used at sub-mesh level are referred to as \a
local ones.
</li>
<li>Bottom-up way, using \ref modifying_meshes_page "mesh modification"
operations, especially \ref extrusion_page "extrusion" and \ref
- revolution_page "revolution". To create an empty mesh not based on
+ revolution_page "revolution". To create an empty mesh not based on a
geometry, use the same dialog as to \ref constructing_meshes_page
- "construct the mesh on geometry" but do not specify any geometry
- nor meshing algorithm.
+ "construct the mesh on geometry" but specify neither the geometry
+ nor meshing algorithms.
</li>
- <li>The mesh can be \ref importing_exporting_meshes_page "imported" from
+ <li>The mesh can be \subpage importing_exporting_meshes_page "imported" from
(and exported to) the file in MED, UNV, STL, CGNS, DAT, GMF and
SAUVE formats.
</li>
- <li>The 3D mesh can be generated from the 2D mesh, \ref
- importing_exporting_meshes_page "imported" or manually created. To
- setup the meshing parameters of a mesh not based on geometry, just
- invoke \ref editing_meshes_page "Edit mesh / sub-mesh" command on
- your 3D mesh.
+ <li>The 3D mesh can be generated from the 2D mesh not based on the geometry,
+ which was either \ref importing_exporting_meshes_page "imported" or created in
+ other way. To setup the meshing parameters of a mesh not based on a geometry,
+ just invoke \ref editing_meshes_page "Edit mesh / sub-mesh" command on
+ your 2D mesh.
</li>
<li>Several meshes can be \subpage building_compounds_page "combined"
into a new mesh.
sub-meshes.
The \b structure of a SALOME mesh is described by nodes and elements based on
-these nodes. Geometry of the element is defined by the sequence of
+these nodes. The geometry of an element is defined by the sequence of
nodes constituting it and
the <a href="http://www.code-aster.org/outils/med/html/connectivites.html">
connectivity convention </a> (adopted from MED library). Definition of
-the element basing on elements of lower dimension is NOT supported.
+the element basing on the elements of a lower dimension is NOT supported.
\anchor mesh_entities
The mesh can include the following entities:
<ul>
-<li>\b Node — an entity of a mesh defining a position in 3D
+<li>\b Node — a mesh entity defining a position in 3D
space with coordinates (x, y, z).</li>
-<li>\b Edge (or segment) — 1D element of a mesh linking two nodes.</li>
-<li>\b Face — 2D element of a mesh representing a part of
+<li>\b Edge (or segment) — 1D mesh element linking two nodes.</li>
+<li>\b Face — 2D mesh element representing a part of
surface bound by links between face nodes. A face can be a
triangle, quadrangle or polygon.</li>
-<li>\b Volume — 3D element of a mesh representing a part of 3D
+<li>\b Volume — 3D mesh element representing a part of 3D
space bound by volume facets. Nodes of a volume describing each
facet are defined by
the <a href="http://www.code-aster.org/outils/med/html/connectivites.html">
MED connectivity convention.</a> A volume can be a tetrahedron, hexahedron,
pentahedron, pyramid, hexagonal prism or polyhedron.</li>
-<li>\b 0D element — element of a mesh defined by one node.</li>
-<li>\b Ball element — discrete element of a mesh defined by a
+<li>\b 0D element — mesh element defined by one node.</li>
+<li>\b Ball element — discrete mesh element defined by a
node and a diameter.</li>
</ul>
Every mesh entity has an attribute associating it to a sub-shape it is
generated on (if any). The node generated on the geometrical edge or
surface in addition stores its position in parametric space of the
-associated geometrical entity.
+associated geometrical entity. This attribute is set up by meshing
+algorithms generating elements and nodes.
+
+Mesh entities are identified by integer IDs starting from 1.
+Nodes and elements are counted separately, i.e. there can be a node
+and element with the same ID.
-SALOME supports elements of second order, without central node
-(quadratic triangle, quadrangle, tetrahedron, hexahedron, pentahedron
-and pyramid) and with central nodes (bi-quadratic triangle and
-quadrangle and tri-quadratic hexahedron).<br>
-Quadratic mesh can be obtained in two ways:
+SALOME supports elements of second order, without a central node
+(quadratic triangle, quadrangle, polygon, tetrahedron, hexahedron,
+pentahedron and pyramid) and with central nodes (bi-quadratic triangle
+and quadrangle and tri-quadratic hexahedron).<br>
+Quadratic mesh can be obtained in three ways:
- Using a global \ref quadratic_mesh_anchor "Quadratic Mesh"
hypothesis. (Elements with the central node are not generated in this way).
- Using \ref convert_to_from_quadratic_mesh_page operation.
-
+- Using an appropriate option of some meshing algorithms, which
+generate elements of several dimensions starting from mesh segments.
*/
