Reading and writing files#

The FileIO class is used for all file-based data exchanges.

Native PMDAT format#

PMDAT is the native file format for PyPrimeMesh. It contains all data associated with the active model.

This includes geometry, mesh, topology, controls, labels, and zones.

The model data can be read from and written to the PMDAT format using the FileIO.read_pmdat() and FileIO.write_pmdat() methods with parameters defined in the FileReadParams and FileWriteParams classes respectively.

from ansys.meshing import prime

# Start Ansys Prime Server and get the model
prime_client = prime.launch_prime()
model = prime_client.model

# Download and read an example PMDAT file
mixing_elbow = prime.examples.download_elbow_pmdat()
params = prime.FileReadParams(model=model)
prime.FileIO(model).read_pmdat(file_name=mixing_elbow, file_read_params=params)

Tip

Files can be read or imported based on file extension using the Mesh.read() method in the Lucid API. The method supports PyPrimeMesh’s native format, various CAD formats, and solver mesh files.

Import CAD files#

The FileIO.import_cad() method allows you to import CAD files and set parameters for importing files using the ImportCadParams class.

CAD reader routes#

You can specify the import route for CAD files using the CadReaderRoute class.

params = prime.ImportCadParams(
    model=model, cad_reader_route=prime.CadReaderRoute.SPACECLAIM
)
prime.FileIO(model).import_cad(file_name=mixing_elbow, params=params)

Alternatively, you can use the Mesh class in the Lucid API:

mesh_util = prime.lucid.Mesh(model=model)
mesh_util.read(file_name=mixing_elbow, cad_reader_route=prime.CadReaderRoute.SPACECLAIM)

Four CAD import routes are available in PyPrimeMesh:

  • Program Controlled: Automatically chooses the best route based on the CAD format. This route uses the Native route if available, the SpaceClaim route for SCDOC file formats, and the Workbench route for all other file formats.

  • Native: Imports selected natively supported file formats like FMD (*.fmd), ACIS (*.sat, *.sab), Parasolid (*.x_t, *.x_b), JTOpen (*.jt, *.plmxml), and STL (*.stl).

  • SpaceClaim: Uses SCDM to import supported CAD files from the SpaceClaim reader. Only the Windows platform supports importing SpaceClaim files.

  • Workbench: Uses Workbench to import supported CAD files from the Workbench reader.

Note

Program Controlled and SpaceClaim route imports JT files containing only faceted data. Workbench and Native does not support importing JT files containing only faceted data.

To view the CAD supported for the Workbench route on different platforms, see CAD Support on the Ansys website.

Note

When deploying scripts using SpaceClaim or Workbench CAD readers, ensure that the CAD configuration and in-app defaults are consistent in the deployed environment.

Note

You must install and configure Workbench CAD readers or plug-ins (Ansys Geometry Interfaces) while installing Ansys Workbench.

Append CAD files#

The ImportCadParams.append parameter allows you to append a CAD file to the model:

params = prime.ImportCadParams(model=model, append=True)
prime.FileIO(model).import_cad(file_name="cad_to_append.scdoc", params=params)

Alternatively, you can use the Mesh class in the Lucid API:

mesh_util = prime.lucid.Mesh(model=model)
mesh_util.read("cad_to_append.scdoc", append=True)

Parametric CAD update#

Parametric CAD update can be used while importing CAD files that have parameters defined that can be accessed by Workbench CAD readers.

This code gets existing CAD parameters while importing:

params = prime.ImportCadParams(model=model)
params.cad_reader_route = prime.CadReaderRoute.WORKBENCH
result = prime.FileIO(model).import_cad(file_name="parametric_cad.scdoc", params=params)

>>> print(result.cad_parameters)

{'my_param': 1}

This code sets the parameters that are used for the import:

params = prime.ImportCadParams(model=model)
params.cad_reader_route = prime.CadReaderRoute.WORKBENCH
params.cad_update_parameters = {"my_param": 2}
result = prime.FileIO(model).import_cad(file_name="parametric_cad.scdoc", params=params)

>>> print(result.cad_parameters)

{'my_param': 2}

Part management and creation#

PyPrimeMesh has options for part management within the product structure while importing a CAD (Computer Aided Design) model. The CAD model is the top in product hierarchy. A CAD model can have one or more CAD assemblies. The CAD assembly or subassembly has different CAD parts. The CAD part has bodies or other geometric entities. Here is a typical CAD product structure from SpaceClaim:

../_images/cad_structure%282%29.png

Example CAD structure from SpaceClaim#

The PartCreationType class decides whether to create a part per:

  • Model

  • Assembly

  • Part

  • Body

Model#

When you import a CAD model and specify the PartCreationType parameter as MODEL, a single part is created that inherits its name from the CAD model name. The number of zones within the part is identical to the number of bodies within the CAD model.

../_images/creation_model%282%29.png

Part creation by model (from SpaceClaim to PyPrimeMesh part structure)#

Assembly#

When you import a CAD model and specify the PartCreationType parameter as ASSEMBLY, a part per CAD assembly is created where the part name is inherited from the CAD assembly name. The number of zones within each part is identical to the number of bodies within the CAD assembly.

../_images/creation_assembly%282%29.png

Part creation by assembly (from SpaceClaim to PyPrimeMesh part structure)#

Part#

When you import a CAD model and specify the PartCreationType parameter as PART, a part per CAD part is created that inherits the part name from the CAD part name. The number of zones within a part is identical to the number of bodies within the CAD part.

../_images/creation_part%282%29.png

Part creation by part (from SpaceClaim to PyPrimeMesh part structure)#

Body#

When you import a CAD model and specify the PartCreationType parameter as BODY, a part per CAD body is created that inherits the part name from the CAD body name. The number of parts is identical to the number of bodies.

../_images/creation_body%282%29.png

Part creation by body (from SpaceClaim to PyPrimeMesh part structure)#

Import and export solver mesh files#

Tip

File extensions such as CAS (*.cas), MSH (*.msh, *.msh.gz), and CDB (*.cdb) can be imported using the Mesh.read() method and exported using the Mesh.write() method in the Lucid API.

Import solver mesh files#

Note

All import methods have the optional parameter to append imported files to an existing model.

Export solver mesh files#

Read and write size field files#

Native PSF format#

Fluent Meshing format#

The FileIO.import_fluent_meshing_size_field() method allows you to import Fluent Meshing’s size field (*.sf, *.sf.gz) file.