msh2geo: Convert gmsh mesh in geo format

SYNOPSIS

  msh2geo [-zr|-rz] input[.msh] > output.geo

DESCRIPTION

Convert a gmsh `.msh' into `.geo' one. The output goes to standart output. See the gmsh documentation for a detailed description of the `.mshcad' input file for gmsh.

EXAMPLES

  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

COORDINATE SYSTEM OPTION

Most of rheolef codes are coordinate-system independant. The coordinate system is specified in the geometry file `.geo'.

-zr
-rz: the 2d mesh is axisymmetric: zr (resp. rz) stands when the symmetry is related to the first (resp. second) coordinate.

NOTES

Pk triangle, when k>=5, may have internal nodes renumbered: from the

GMSH DOCUMENTATION

  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.

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, msh2geo fix the corresponding internal nodes numbering during the conversion.

Pk tetrahedrons and hexaedrons in gmsh and rheolef has not the same edge-node order nd orientation. E.g. for tetrahedrons, edges 13 and 23 should be swaped and reoriented as 32 and 31. Thus, msh2geo fix the corresponding internal nodes numbering.

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 visualisation with gnuplot face fill.

See also hexa edges orient and faces numbers and orient.

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.

Support for high order >= 6 element ? not documented in gmsh, but gmsh supports it at run

msh2geo (1rheolef)