.TH "msh2geo" 1rheolef "Sat Mar 13 2021" "Version 7.1" "rheolef" \" -*- nroff -*-
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.SH NAME
msh2geo \- convert gmsh mesh in geo format (rheolef-7\&.1)
.PP
     
.SH "SYNOPSIS"
.PP
.nf
msh2geo [-zr|-rz] < file[.msh] > output.geo
msh2geo [-zr|-rz]   file[.msh] > output.geo
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.PP
 
.SH "DESCRIPTION"
Convert a \fC\&.msh\fP file, as generated by the \fCgmsh\fP mesh generator, into a \fC\&.geo\fP one for Rheolef\&. The output goes to standard output\&. The input comes either from standard input or from a file\&.
.SH "EXAMPLES"
.PP
.nf
    gmsh -2 toto.mshcad -o toto.msh
    msh2geo < toto.msh > toto.geo

    gmsh -2 -order 2 toto.mshcad -o toto2.msh
    msh2geo < toto2.msh > toto2.geo
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.PP
 See the \fCgmsh\fP documentation for a detailed description of the \fC\&.mshcad\fP input file for \fCgmsh\fP\&.
.SH "OPTIONS"
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\fC-cartesian\fP 
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\fC-rz\fP 
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\fC-zr\fP 
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.RS 4
Specifies the coordinate system\&. The default is \fCcartesian\fP while \fC-rz\fP and \fC-zr\fP denotes some axisymmetric coordinate systems\&. Recall that most of Rheolef codes are coordinate-system independent and the coordinate system is specified in the geometry file \fC\&.geo\fP\&. 
.RE
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.SH "IMPLEMENTATION NOTES"
There is an issue for curved boundaries, using high order Pk polynomial elements\&. Pk triangle, when k>=5, may have internal nodes renumbered\&. From the gmsh documentation: 
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The nodes of a curved element are numbered in the following order:

  the element principal vertices;
  the internal nodes for each edge;
  the internal nodes for each face;
  the volume internal nodes. 

The numbering for face and volume internal nodes is recursive,
i.e., the numbering follows that of the nodes of an embedded face/volume.
The higher order nodes are assumed to be equispaced on the element. 

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.PP
 In Rheolef, internal triangle nodes are numbered from left to right and then from bottom to top\&. The numbering differ for triangle when k >= 5\&. Thus, \fCmsh2geo\fP fixes the corresponding internal nodes numbering during the conversion\&.
.PP
Pk tetrahedrons and hexahedrons in gmsh and Rheolef has not the same edge-node order and orientation\&. E\&.g\&. for tetrahedrons, edges 13 and 23 should be swapped and reoriented as 32 and 31\&. Thus, \fCmsh2geo\fP also fix the corresponding internal nodes numbering\&.
.SH "TODO"
Fix for P3-tetra: swap edges orientations for 3,4,5 and swap faces 1 and 2\&. Check P4(T) for face orientation\&. Perform face visualization with gnuplot face fill\&.
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See also hexa edges orient and faces numbers and orient\&.
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Check that node are numbered by vertex-node, then edge-node, then face(tri,qua)-node and then volume(T,P,H)-node\&. Otherwise, renumber all nodes\&.
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Support for high order >= 6 element is not documented in gmsh, but gmsh supports it at run
.SH "IMPLEMENTATION"
This documentation has been generated from file main/sbin/msh2geo\&.cc 
.SH AUTHOR
Pierre  Saramito  <Pierre.Saramito@imag.fr>
.SH COPYRIGHT
Copyright   (C)  2000-2018  Pierre  Saramito  <Pierre.Saramito@imag.fr>
GPLv3+: GNU GPL version 3 or later  <http://gnu.org/licenses/gpl.html>.
This  is  free  software:  you  are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.