FileMeshGenerator

Supported File Formats

The FileMeshGenerator is the default type for MOOSE and as the name suggests it reads the mesh from an external file. MOOSE supports reading and writing a large number of formats and could be extended to read more.

Reading with the FileMeshGenerator. These capabilities are inherited from the libmesh file IO readers.

Writing (using the Outputs block). We list these formats here for convenience if you are considering using MOOSE as a mesh file converter.

These formats (for writing meshes) are supported by libmesh and could easily be added to MOOSE if needed:

Unsupported File Formats

These file formats are unsupported, however, using other tools they can be converted to supported formats. In general, the mesh must respect the limitations of the target format for a successful conversion.

Tools offering conversion capabilities:

• Paraview

• meshio, can also be installed with mamba/conda

• em2ex

The conversion capabilities to be able to read those files are summarized here for convenience:

Extra element integer

When reading a mesh file in Sandia's ExodusII format, users can use parameter exodus_extra_element_integers to load elemental variables for setting extra element integers of the mesh. The names of the extra element integers will be the same as the names of the element variables in the mesh file.

Exodus restart

This generator can also be used for restarting variables from the Exodus file format. In order to indicate that the mesh file can be used to restart variables, simply set the parameter use_for_exodus_restart = true. The initial_from_file_var parameter must also be set in the variables sub-block as described in Restart in order to perform variable restart.

Additional documentation about restarting from Exodus may be found in the restart-recovery page.

Loading a split mesh

Mesh splits usually do not require a FileMeshGenerator, they can be performed and loaded from the command line. The only use case for loading a split mesh using a FileMeshGenerator is to perform additional mesh generation on the split. For example, a 2D split mesh can be pre-split before extrusion to avoid ever having to load the full 3D mesh in serial.

To load a split mesh using the FileMeshGenerator, split your mesh as usual using the command line:

- mpirun -n 4 <executable> -i <input_file> --split-mesh 16 --split-file mesh_splitted

then load it with the FileMeshGenerator input parameter by using distributed meshes with the command line option:

- mpirun -n 4 <executable> -i <input_file> --distributed-mesh

Input file:

[fmg]
  type = FileMeshGenerator
  file = 'mesh_splitted.cpr'
[]

Input Parameters