1. Python Package Usage, CAD to CSG conversion#

The main class is CadToCsg() which converts CAD geometry to Constructive Solid Geometry (CSG). There are many arguments that can be passed into the CadToCsg() class which are documented in the Python API reference section of the documentation.

If you have install GEOUNED and FreeCAD into your system Python then you can simply run a .py script with Python. The most minimal use case below shows GEOUNED being imported and the CadToCsg being used to convert a STEP CAD file called ‘cuboid.stp’ into a vanity of CSG format. The example makes use of default attributes.

import geouned
geo = geouned.CadToCsg()
geo.load_step_file(filename='cuboid.stp')
geo.start()
geo.export_csg()

Users can change geouned.Options(), geouned.Settings(), geouned.Tolerances() and geouned.NumericFormat() to suit the conversion desired. The following example shows a usage with every attributes specified.

import geouned

my_options = geouned.Options(
    forceCylinder=False,
    newSplitPlane=True,
    delLastNumber=False,
    enlargeBox=2,
    nPlaneReverse=0,
    splitTolerance=0,
    scaleUp=True,
    quadricPY=False,
    Facets=False,
    prnt3PPlane=False,
    forceNoOverlap=False,
)

my_settings = geouned.Settings(
    matFile="",
    voidGen=True,
    debug=False,
    compSolids=True,
    simplify="no",
    exportSolids="",
    minVoidSize=200.0,
    maxSurf=50,
    maxBracket=30,
    voidMat=[],
    voidExclude=[],
    startCell=1,
    startSurf=1,
    sort_enclosure=False,
)

my_tolerances = geouned.Tolerances(
    relativeTol=False,
    relativePrecision=0.000001,
    value=0.000001,
    distance=0.0001,
    angle=0.0001,
    pln_distance=0.0001,
    pln_angle=0.0001,
    cyl_distance=0.0001,
    cyl_angle=0.0001,
    sph_distance=0.0001,
    kne_distance=0.0001,
    kne_angle=0.0001,
    tor_distance=0.0001,
    tor_angle=0.0001,
    min_area=0.01,
)
my_numeric_format = geouned.NumericFormat(
    P_abc="14.7e",
    P_d="14.7e",
    P_xyz="14.7e",
    S_r="14.7e",
    S_xyz="14.7e",
    C_r="12f",
    C_xyz="12f",
    K_xyz="13.6e",
    K_tan2="12f",
    T_r="14.7e",
    T_xyz="14.7e",
    GQ_1to6="18.15f",
    GQ_7to9="18.15f",
    GQ_10="18.15f",
)

geo = geouned.CadToCsg(
    options=my_options,
    settings=my_settings,
    tolerances=my_tolerances,
    numeric_format=my_numeric_format,
)

geo.load_step_file(
    filename="cuboid.stp",
    skip_solids=[],
)

geo.start()

geo.export_csg(
    title="Converted with GEOUNED",
    geometryName="csg",
    outFormat=(
        "openmc_xml",
        "openmc_py",
        "serpent",
        "phits",
        "mcnp",
    ),
    volSDEF=True,
    volCARD=False,
    UCARD=None,
    dummyMat=True,
    cellCommentFile=False,
    cellSummaryFile=False,
)

You can also load up JSON configuration files from the API. The JSON file format is also usable with the Geouned Command Line Interface and there are more complete examples of JSON files on that section of the documentation. For this example we assume you have a JSON file called ‘config.json’ in the same directory as the script.

import geouned

geo = geouned.CadToCsg.from_json("config.json")
geo.start()
geo.export_csg()
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