A Python package that converts Brep CAD geometry files to h5m geometry files compatible with DAGMC simulations.

The method uses gmsh to create a conformal mesh of the geometry. The mesh is then converted into a h5m file using either the vertices-to-h5m (default) or stl-to-h5m package.

Create a new enviroment and activate the enviroment.

conda create --name my_env
conda activate my_env

Then install this package

conda install -c fusion-energy -c conda-forge brep_to_h5m

The above command should also install moab and gmsh

Create a new enviroment and activate the enviroment.

conda create --name my_env
conda activate my_env

Install dependancies that are not installed with pip (MOAB and GMSH)

conda install -c conda-forge moab
conda install -c conda-forge gmsh
conda install -c conda-forge python-gmsh

Then install this package

pip install brep_to_h5m

See the examples folder for a complete workflow from geometry creation to conversion to h5m and then use in and OpenMC simulation.

To make a Brep file with merged surfaces consider using the Paramak as it has a export_brep method that merges the shared surfaces for Brep files.

Starting with a Brep file that has shared surfaces the following command should produce a DAGMC compatible h5m file.

from brep_to_h5m import brep_to_h5m

brep_to_h5m(
    brep_filename='my_brep_file_with_merged_surfaces.brep',
    material_tags=[
        'material_for_volume_1',
        'material_for_volume_2',
        'material_for_volume_3',
        'material_for_volume_4',
        'material_for_volume_5',
        'material_for_volume_6',
        'material_for_volume_7',
        'material_for_volume_8',
    ],
    h5m_filename='dagmc.h5m',
    min_mesh_size= 30,
    max_mesh_size = 50,
    mesh_algorithm = 1,
)

The resulting dagmc.h5m file can now be used in neutronics simulation with DAGMC enabled transport codes.

Many thanks to @makeclean for suggesting gmsh for meshing and Brep for the CAD file format. Also for showing the way forwards by starting gmsh2dagmc.