Meshes generated with Gmsh can be converted to OGS meshes, in particular to VTU
Currently, the only supported Gmsh format is 2.1, which can be specified for
example with the command line flag
-format msh2 when executing
Gmsh writes all elements (unless specified otherwise) including the lower
dimensional elements, usually model boundaries.
Whereas for OGS we separate the so called “bulk” mesh and the boundary (or
whether the line elements are removed or written in separate files.
A 2D-mesh with two physical groups (MaterialIDs) was generated with Gmsh. It also includes the outer boundary and inner boundary line elements.
All files are stored in Tests/Data/MeshLib/:
A2.vtu, and the boundary meshes
GMSH2OGS creates different meshes from the same input depending on the
-b flags; the results are shown (z-translated) in the figure below.
GMSH2OGS -i A2-gmsh.msh -o A2.vtu
-eflag results in a single VTU file, now without the line elements.
-bflag gives a single VTU file as in the first case and additional eight files, each containing a line-element mesh corresponding to the physical groups; these are the white lines in the figure, shown again z-translated.
-b) produces a single VTU file without the line elements and additional eight boundary (subdomain) files.