mirror of
https://git.salome-platform.org/gitpub/modules/smesh.git
synced 2024-09-23 11:12:51 +05:00
0921263864
Fix a leak of PropagationMgrData + Do not use volumes for preview of Extrusion + Fix a regression: empty groups are not removed with contents + avoid too long waiting at creation of hypotheses due to use of GEOMUtils::PreciseBoundingBox() in SMESH_Mesh::GetShapeDiagonalSize()
110 lines
4.9 KiB
Plaintext
110 lines
4.9 KiB
Plaintext
/*!
|
|
|
|
\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".
|
|
|
|
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
|
|
- <em>meshing parameters</em> (\ref
|
|
basic_meshing_algos_page "meshing algorithms" and
|
|
characteristics (e.g. element size) of a
|
|
required mesh encapsulated in \ref about_hypo_page "hypothesis"
|
|
objects).
|
|
|
|
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>
|
|
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
|
|
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
|
|
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.
|
|
</li>
|
|
<li>The mesh can be \ref 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>
|
|
<li>Several meshes can be \subpage building_compounds_page "combined"
|
|
into a new mesh.
|
|
</li>
|
|
<li>The whole mesh or its part (sub-mesh or group) can be
|
|
\subpage copy_mesh_page "copied" into a new mesh.
|
|
</li>
|
|
<li>A new mesh can be created from a transformed, e.g. \ref
|
|
translation_page "translated", part of the mesh.</li>
|
|
</ul>
|
|
|
|
Meshes can be edited using the MESH functions destined for
|
|
\ref modifying_meshes_page "modification" of meshes.
|
|
|
|
Attractive meshing capabilities include:
|
|
- 3D and 2D \ref viscous_layers_anchor "Viscous Layers" (boundary
|
|
layers of highly stretched elements beneficial for high quality
|
|
viscous computations);
|
|
- automatic conformal transition between tetrahedral and hexahedral
|
|
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
|
|
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.
|
|
|
|
\anchor mesh_entities
|
|
The mesh can include the following entities:
|
|
<ul>
|
|
<li>\b Node — an entity of a mesh 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
|
|
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
|
|
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
|
|
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.
|
|
|
|
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:
|
|
- 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.
|
|
|
|
*/
|