smesh/doc/salome/gui/SMESH/input/smeshpy_interface.rst

.. _smeshpy_interface_page:

****************
Python interface
****************

Python API of SALOME Mesh module defines several classes that can
be used for easy mesh creation and edition.

Documentation of SALOME %Mesh module Python API is available in two forms:

- `Structured documentation <smeshpy_doc/modules.html>`_, where all methods and classes are grouped by their functionality.

- `Linear documentation <smeshpy_doc/namespaces.html>`_ grouped only by classes, declared in the :ref:`smeshBuilder` and :ref:`StdMeshersBuilder` Python packages.

With SALOME 7.2, the Python interface for Mesh has been slightly modified to offer new functionality.

You may have to modify your scripts generated with SALOME 6 or older versions.

Please see :ref:`smesh_migration_page`.

Class :ref:`smeshBuilder.smeshBuilder` provides an interface to create and handle
meshes. It can be used to create an empty mesh or to import mesh from the data file.

As soon as a mesh is created, it is possible to manage it via its own
methods, described in class :ref:`smeshBuilder.Mesh` documentation.

Class :ref:`smeshstudytools.SMeshStudyTools` provides several methods to manipulate mesh objects in Salome study. 

A usual workflow to generate a mesh on geometry is following:

#. Create an instance of :ref:`smeshBuilder.smeshBuilder`:
	.. code-block:: python
		:linenos:

		from salome.smesh import smeshBuilder
		smesh = smeshBuilder.New( salome.myStudy )

#. Create a :ref:`smeshBuilder.Mesh` object:

	.. code-block:: python
		:linenos:

		mesh = :ref:`smeshBuilder.smeshBuilder.Mesh`smesh.Mesh( geometry )

#. Create and assign :ref:`basic_meshing_algos_page` by calling corresponding methods of the mesh. If a sub-shape is provided as an argument, a :ref:`constructing_submeshes_page` is implicitly created on this sub-shape:
	.. code-block:: python
		:linenos:

		regular1D = :ref:`smeshBuilder.Mesh.Segment` 
		mefisto   = :ref:`smeshBuilder.Mesh.Triangle` ( smeshBuilder.MEFISTO )
		# use other triangle algorithm on a face -- a sub-mesh appears in the mesh
		netgen    = :ref:`smeshBuilder.Mesh.Triangle` ( smeshBuilder.NETGEN_1D2D, face )

#. Create and assign :ref:`about_hypo_page` by calling corresponding methods of algorithms:
	.. code-block:: python
		:linenos:

		segLen10 = :ref:`StdMeshersBuilder.StdMeshersBuilder_Segment.LocalLength`( 10. )
		maxArea  = :ref:`StdMeshersBuilder.StdMeshersBuilder_Segment.LocalLength`( 100. )
		netgen.SetMaxSize( 20. )
		netgen.SetFineness( smeshBuilder.VeryCoarse )
  
#. :ref:`compute_anchor` the mesh (generate mesh nodes and elements):
	.. code-block:: python
		:linenos:

		:ref:`Mesh.Compute`()

An easiest way to start with Python scripting is to do something in
GUI and then to get a corresponding Python script via 
**File > Dump Study** menu item. Don't forget that you can get
all methods of any object in hand (e.g. a mesh group or a hypothesis)
by calling *dir()* Python built-in function.

All methods of the Mesh Group can be found in :ref:`tui_create_standalone_group` sample script.

An example below demonstrates usage of the Python API for 3d mesh
generation and for retrieving information on mesh nodes and elements.

.. _example_3d_mesh:

Example of 3d mesh generation:
##############################

.. _3dmesh.py:

``3dmesh.py`` 


.. literalinclude:: ../../../examples/3dmesh.py
    :linenos:
    :language: python

:download:`../../../examples/3dmesh.py`

Examples of Python scripts for Mesh operations are available by
the following links:

- :ref:`tui_creating_meshes_page`
- :ref:`tui_defining_hypotheses_page`
- :ref:`tui_grouping_elements_page`
- :ref:`tui_filters_page`
- :ref:`tui_modifying_meshes_page`
- :ref:`tui_transforming_meshes_page`
- :ref:`tui_viewing_meshes_page`
- :ref:`tui_quality_controls_page`
- :ref:`tui_measurements_page`
- :ref:`tui_work_on_objects_from_gui`
- :ref:`tui_notebook_smesh_page`
- :ref:`tui_cartesian_algo`
- :ref:`tui_use_existing_faces`
- :ref:`tui_prism_3d_algo`
- :ref:`tui_generate_flat_elements_page`



.. toctree::
	:maxdepth: 2

	smesh_migration.rst