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Commit fd75ef71 authored by Christophe Geuzaine's avatar Christophe Geuzaine
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.\" $Id: gmsh.1,v 1.46 2003-03-06 23:01:17 geuzaine Exp $
.TH Gmsh 1 "12 November 2001" "Gmsh > 1.30" "Gmsh Manual Pages"
.\" $Id: gmsh.1,v 1.47 2003-06-14 17:44:36 geuzaine Exp $
.TH Gmsh 1 "14 June 2003" "Gmsh 1.45" "Gmsh Manual Pages"
.UC 4
.\" ********************************************************************
.SH NAME
......@@ -11,85 +11,18 @@ with built-in pre- and post-processing facilities
.\" ********************************************************************
.SH DESCRIPTION
\fIGmsh\fR is an automatic three-dimensional finite element mesh
generator, primarily Delaunay, with built-in pre- and post-processing
generator (primarily Delaunay) with build-in CAD and post-processing
facilities. Its primal design goal is to provide a simple meshing tool
for academic test cases with parametric input and up to date
visualization capabilities. One of the strengths of \fIGmsh\fR is its
ability to respect a characteristic length field for the generation of
adapted meshes on lines, surfaces and volumes. These adapted meshes
can be mixed with simple structured (transfinite, elliptic, etc.)
meshes in order to augment the flexibility.
.SS Geometrical entity definition
Parameterized geometries are created by successively defining points,
oriented curves (segments, circles, ellipsis, splines, etc.), oriented
surfaces (plane surfaces, ruled surfaces, etc.) and volumes. Compound
groups of geometrical entities can be defined, based on these elementary
parameterized and scriptable geometric entities.
.SS Mesh generation
A finite element mesh is a tessellation of a given subset of R^3 by
elementary geometrical elements of various shapes (in this case lines,
triangles, quadrangles, tetrahedra, prisms and hexahedra), arranged in
such a way that two of them intersect, if they do, along a common
face, edge or node, and never otherwise. All the finite element meshes
produced by \fIGmsh\fR as unstructured, even if they were generated in
a structured way. This implies that the elementary geometrical
elements are defined only by an ordered list of their vertices (which
allows the orientation of all their lower order geometrical entities)
but no predefined relation is assumed between any two elementary
elements.
visualization capabilities. One of its strengths is the ability to
respect a characteristic length field for the generation of adapted
meshes on lines, surfaces and volumes, and to mix these meshes with
simple structured grids.
.PP
The procedure follows the same order as for the geometry creation:
curves are discretized first; the mesh of the curves is then used to
mesh the surfaces; then the mesh of the surfaces is used to mesh the
volumes. This automatically assures the continuity of the mesh when,
for example, two surfaces share a common curve. Every meshing step is
constrained by the characteristic length field, which can be uniform,
specified by characteristic length associated to elementary
geometrical entities, or associated to another mesh (the background
mesh).
.PP
For each meshing step (i.e. the discretization of lines, surfaces and
volumes), all structured mesh directives are executed first, and serve
as additional constraints for the unstructured parts. The implemented
Delaunay algorithm is subdivided in the following five steps for
surface/volume discretization:
.TP 4
.B 1.
trivial meshing of a box including the convex polygon/polyhedron
defined by the boundary nodes resulting from the discretization of the
curves/surfaces;
.TP 4
.B 2.
creation of the initial mesh by insertion of all the nodes on the
curves/surfaces thanks to the Bowyer algorithm;
.TP 4
.B 3.
boundary restoration to force all the edges/faces of the
curves/surfaces to be present in the initial mesh;
.TP 4
.B 4.
suppression of all the unwanted triangles/tetrahedra (in
particular those containing the nodes of the initial box);
.TP 4
.B 5.
insertion of new nodes by the Bowyer algorithm until the
characteristic size of each simplex is lower or equal to the
characteristic length field evaluated at the center of its
circumscribed circle/sphere.
.SS External solver interface
External solvers can be interfaced with Gmsh through a socket
mechanism, which permits to easily launch computations either locally
or on remote computers, and to collect and exploit the simulation
results within Gmsh.
.SS Scalar, vector and tensor field visualization
Multiple post-processing scalar or vector maps can be loaded and
manipulated (globally or individually) along with the geometry and the
mesh. Scalar fields are represented by iso-value curves or color maps
and vector fields by three-dimensional arrows or displacement
maps. Post-processor functions include offsets, elevation, interactive
color map modification, range clamping, interactive animation, vector
postscript output, etc. All post-processing options can be accessed
either interactively or through the input ascii files.
\fIGmsh\fR is built around four modules: geometry, mesh, solver and
post-processing. The specification of any input to these modules is
done either interactively using the graphical user interface or in
ASCII text files using \fIGmsh\fR's own scripting language.
.\" ********************************************************************
.SH GEOMETRY OPTIONS
.TP 4
......@@ -124,9 +57,9 @@ select the two-dimensional mesh algorithm (default: iso).
.TP 4
.B \-smooth int
set the number of smoothing steps (default value is 0).
.\" .TP 4
.\" .B \-degree int
.\" set the degree of the generated elements (default value is 1).
.TP 4
.B \-order int
set the order of the generated elements (default value is 1).
.TP 4
.B \-scale float
apply a global scaling factor to the model (default value is 1.0).
......@@ -151,15 +84,15 @@ model.
.B \-histogram
print mesh quality histogram.
.TP 4
.B \-interactive
display the 2D mesh construction interactively if the anisotropic mesh
algorithm is selected.
.TP 4
.B \-extrude
use the old extrusion mesh generator.
.TP 4
.B \-recombine
recombine meshes from the old extrusion mesh generator.
.TP 4
.B \-interactive
display the 2D mesh construction interactively if the anisotropic mesh
algorithm is selected.
.\" ********************************************************************
.SH POST-PROCESSING OPTIONS
.TP 4
......@@ -184,13 +117,19 @@ convert an ascii view into a binary one.
suppress the double buffer. Use this options if you use \fIGmsh\fR on
a remote host without GLX.
.TP 4
.B \-fontsize int
specify the font size for the GUI (default: 12)
.TP 4
.B \-scheme string
specify FLTK scheme
.TP 4
.B \-alpha
enable alpha blending.
.TP 4
.B \-notrack
don't use trackball mode for rotations.
.TP 4
.B \-display disp
.B \-display string
specify display.
.TP 4
.B \-perspective
......@@ -202,15 +141,15 @@ use perspective instead of orthographic projection.
start in automatic, geometry, mesh, solver or post-processing mode
(default: automatic).
.TP 4
.B \-string string
.B \-v int
set verbosity level (default: 2).
.TP 4
.B \-string "string"
parse string before project file.
.TP 4
.B \-option file
parse option file before GUI creation.
.TP 4
.B \-v int
set verbosity level (default: 2).
.TP 4
.B \-version
show version number.
.TP 4
......@@ -230,3 +169,14 @@ Remacle (Remacle@scorec.rpi.edu).
Gmsh examples (\fI/usr/doc/gmsh-*/\fR),
.br
Gmsh homepage (\fIhttp://www.geuz.org/gmsh/\fR).
.PP
The full documentation for Gmsh is maintained as a Texinfo manual. If
the
.B info
and
.B gmsh
programs are properly installed at your site, the command
.IP
.B info gmsh
.PP
should give you access to the complete manual.
......@@ -26,7 +26,7 @@ generator with built-in pre- and post-processing facilities</h1>
<p>
<h3 align="center">Christophe Geuzaine and Jean-François Remacle</h3>
<p>
<h3 align=center>Version <a href="doc/VERSIONS">1.45</a>, 12 June 2003</h3>
<h3 align=center>Version <a href="doc/VERSIONS">1.45</a>, 15 June 2003</h3>
<p>
<center>
<a href="#Description">Description</a> |
......
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