OpenFOAM-12/tutorials/mesh/foamyHexMesh/blob/system/topoSetDict

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  dev
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      topoSetDict;
}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

actions
(
    {
        name    z;
        type    cellSet;
        action  new;
        source  boxToCell;
        sourceInfo
        {
            box (-100 -100 -0.2)(100 100 100);
        }
    }

    {
        name    zf;
        type    faceSet;
        action  new;
        source  cellToFace;
        sourceInfo
        {
            set    z;
            option all;
        }
    }

    {
        name    z;
        type    cellSet;
        action  invert;
    }

    {
        name    zf;
        type    faceSet;
        action  subset;
        source  cellToFace;
        sourceInfo
        {
            set    z;
            option all;
        }
    }

    // ~~~~~~~~~~~~~~~~ //

    {
        name    x;
        type    cellSet;
        action  new;
        source  boxToCell;
        sourceInfo
        {
            box (-0.32 -100 -100)(100 100 100);
        }
    }

    {
        name    xf;
        type    faceSet;
        action  new;
        source  cellToFace;
        sourceInfo
        {
            set    x;
            option all;
        }
    }

    {
        name    x;
        type    cellSet;
        action  invert;
    }

    {
        name    xf;
        type    faceSet;
        action  subset;
        source  cellToFace;
        sourceInfo
        {
            set    x;
            option all;
        }
    }

    // ~~~~~~~~~~~~~~~~ //

    {
        name    sp;
        type    cellSet;
        action  new;
        source  sphereToCell;
        sourceInfo
        {
            centre (-0.3 -0.3 -0.3);
            radius 0.4;
        }
    }

    {
        name    spf;
        type    faceSet;
        action  new;
        source  cellToFace;
        sourceInfo
        {
            set    sp;
            option all;
        }
    }

    {
        name    sp;
        type    cellSet;
        action  invert;
    }

    {
        name    spf;
        type    faceSet;
        action  subset;
        source  cellToFace;
        sourceInfo
        {
            set    sp;
            option all;
        }
    }
);

// ************************************************************************* //