\page additional_hypo_page Additional Hypotheses
-\n <b>Additional Hypotheses</b> can be applied as a supplement to the
-main hypotheses, introducing additional concepts to mesh creation.
+\n <b>Additional Hypotheses</b> can be applied as a supplement to
+introducing additional concepts to mesh creation.
Following additional hypotheses can be used together with NETGEN algoritm:
<ul>
-<li><b>Quadrangle Preference</b> - This additional hypothesis can be used together with Netgen 2D algorithm.
-It allows Netgen 2D to build quadrangular meshes.</li>
-<br>
-This hypothesis has one restriction on its work: the total quantity of
-segments on all four sides of the face must be even (divisible by 2).
-
-
<li><b>Viscous Layers</b> additional hypothesis can be used together with NETGEN 3D.
This hypothesis allows creation of layers of highly stretched prisms near
mesh boundary, which is beneficial for high quality viscous
actually the hexahedrons.</li>
</ul>
+<li><b>Quadrangle Preference</b> - This additional hypothesis can be
+ used together with Netgen 2D algorithm.
+It allows Netgen 2D to build quad-dominant meshes.</li>
+<br>
+
For more detailed description of the described above hypothesis please refer SALOME Mesh User's Guide.
*/
\b NETGENPLUGIN plugin is destined for:
- Meshing 1D, 2D and 3D geometric entities.
- - Faces are split into triangular elements.
- - Volumes are split into tetrahedral (pyramidal) elements.
+ - Faces are split into triangular elements. Quad-dominant mesh is
+ also possible.
+ - Solids are split into tetrahedral elements. Pyramids are
+ constructed as a transition from quadrangles to tetrahedra.
- Generating 3D meshes from 2D meshes, working without geometrical objects.
-To manage parameters of the NETGENPLUGIN use \subpage netgen_2d_3d_hypo_page and \subpage additional_hypo_page.
+To manage parameters of the NETGENPLUGIN use \subpage
+netgen_2d_3d_hypo_page and \subpage additional_hypo_page.
+
+Native Netgen mesher usually prints a lot of trace output to the terminal
+window. This output is redirected to some log file by the Plugin. It
+is possible to switch off this redirection by setting up
+KEEP_NETGEN_OUTPUT environment variable.
Also all NETGENPLUGIN functionalities are accessible via
\subpage netgenplugin_python_interface_page "NETGENPLUGIN Python interface".
\image html netgen2d3d.png
<center><em>Hypothesis dialog boxes of <b>Netgen 1D-2D</b> and <b>Netgen
-1D-2D-3D</b> algorithms are same</em></center>
+ 1D-2D-3D</b> algorithms are same</em></center>
<br>
\image html netgen2d3d_only.png
<center><em>Dialog boxes of <b>Netgen 2D</b> and <b>Netgen 3D</b>
-algorithms </em></center>
+ algorithms </em></center>
- <b>Name</b> - allows to define the name for the algorithm (Netgen
2D (or 3D) Parameters by default).
ignored if it is more than <b>Max Size</b>.
- <b>Second Order</b> - if this box is checked in, the algorithm will
create second order mesh.
-- <b>Fineness</b> - ranging from <em>Very Coarse</em> to <em>Very Fine</em>
+- <b>Fineness</b> - ranging from <em>Very Coarse</em> to <em>Very Fine</em>
allows to set the level of meshing detalization using the three
parameters below. You can select \a Custom to define them manually.
- <b>Growth rate</b> - allows to define how much the linear dimensions of
-two adjacent cells can differ (i.e. 0.3 means 30%).
+two adjacent cells can differ (e.g. 0.3 means 30%).
- <b>Nb. Segs per Edge</b> - allows to define the minimum number of
mesh segments in which edges will be split. This parameter is used
only if <b>Limit Size by Surface Curvature</b> is checked.
- <b>Nb Segs per Radius</b> - allows to define the size of
mesh segments and mesh faces in which curved edges and surfaces will
-be split. This parameter is used only if <b>Limit Size by Surface
-Curvature</b> is checked.
-- <b>Limit Size by Surface Curvature</b> - if this box is checked in,
+be split. This value divided by a radius of curvature gives an element
+size at a given point. This parameter is used only if <b>Limit Size by
+ Surface Curvature</b> is checked.
+- <b>Limit Size by Surface Curvature</b> - if this box is checked in,
then size of mesh segments and mesh faces on curved edges and surfaces
is defined using value of <b>Nb Segs per Radius</b> parameter, and
number of segments on straight edges is defined by values of
\b 1D group allows defining the size of 1D elements in either of two ways:
- <b>Number of Segments</b> allows specifying number of segments, that
will split each edge, with equidistant distribution.
-- <b>Local Length</b> can be applied for meshing of edges
-composing geometrical object. Definition of this hypothesis
-consists of setting required \b length of segments.
+- <b>Local Length</b> defines length of segments.
\b 2D group allows defining the size of 2D elements
-- <b>Length from edges</b> if checked in, hypothesis forces building of
-2D mesh elements having a length calculated as an average edge length
+- <b>Length from edges</b> if checked in, size of
+2D mesh elements is defined as an average mesh segment length
for a given wire, else
- <b>Max. Element Area</b> specifies expected maximum element area for
each 2d element.
- <b>Length from faces</b> if checked in, the area of sides of
volumic elements will be equal to an average area of 2D elements, else
- <b>Max. Element Volume</b> specifies expected maximum element volume
-of each 3d element.
+of 3d elements.
\note Netgen algorithm does not strictly follow the input
parameters. The actual mesh can be more or less dense than
required. There are several factors in it:
-- NETGEN does not actually use "NbOfSegments" parameter for discretization of
-edge. This parameter is used only to define the local element size
-(size at the given point), so local sizes of adjacent edges influence
-each other.
+- NETGEN does not actually use <b>Number of Segments</b> parameter for
+discretization of edge. This parameter is used only to define the
+local element size (size at the given point), so local sizes of
+close edges influence each other.
- NETGEN additionally restricts the element size according to edge curvature.
- The local size of segments influences the size of close triangles.
- The order of elements and their size in the 1D mesh generated by
