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

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

Structured documentation, where all methods and classes are grouped by their functionality.
Linear documentation grouped only by classes, declared in the smeshBuilder and 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 Modifing Mesh Python scripts from SALOME 6 and before.

Class 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 Mesh documentation.

Class 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 smeshBuilder:

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

Create a mesh object:

      mesh = smesh.Mesh( geometry )

Create and assign algorithms by calling corresponding methods of the mesh. If a sub-shape is provided as an argument, a sub-mesh is implicitly created on this sub-shape:

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

Create and assign hypotheses by calling corresponding methods of algorithms:

      segLen10 = regular1D.LocalLength( 10. )
      maxArea  = mefisto.MaxElementArea( 100. )
      netgen.SetMaxSize( 20. )
      netgen.SetFineness( smeshBuilder.VeryCoarse )

Compute the mesh (generate mesh nodes and elements):
```
      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 Create a 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 of 3d mesh generation:

 # 3d mesh generation and mesh exploration
 
 import salome
 salome.salome_init()
 from salome.geom import geomBuilder
 geompy = geomBuilder.New(salome.myStudy)
 
 import SMESH
 from salome.smesh import smeshBuilder
 smesh =  smeshBuilder.New(salome.myStudy)
 
 ###
 # Geometry: an assembly of a box, a cylinder and a truncated cone
 # to be meshed with tetrahedra
 ###
 
 # Define values
 name = "ex21_lamp" 
 cote = 60 
 section = 20 
 size = 200 
 radius_1 = 80 
 radius_2 = 40 
 height = 100 
 
 # Build a box
 box = geompy.MakeBox(-cote, -cote, -cote, +cote, +cote, +cote) 
 
 # Build a cylinder
 pt1 = geompy.MakeVertex(0, 0, cote/3) 
 di1 = geompy.MakeVectorDXDYDZ(0, 0, 1) 
 cyl = geompy.MakeCylinder(pt1, di1, section, size) 
 
 # Build a truncated cone
 pt2 = geompy.MakeVertex(0, 0, size) 
 cone = geompy.MakeCone(pt2, di1, radius_1, radius_2, height) 
 
 # Fuse
 box_cyl = geompy.MakeFuse(box, cyl) 
 piece = geompy.MakeFuse(box_cyl, cone) 
 
 # Add to the study
 geompy.addToStudy(piece, name) 
 
 # Create a group of faces
 faces_group = geompy.CreateGroup(piece, geompy.ShapeType["FACE"]) 
 group_name = name + "_grp" 
 geompy.addToStudy(faces_group, group_name) 
 faces_group.SetName(group_name) 
 
 # Add faces to the group
 faces = geompy.SubShapeAllIDs(piece, geompy.ShapeType["FACE"]) 
 geompy.UnionIDs(faces_group, faces) 
 
 ###
 # Create a mesh
 ###
 
 # Define a mesh on a geometry
 tetra = smesh.Mesh(piece, name) 
 
 # Define 1D algorithm and hypothesis
 algo1d = tetra.Segment() 
 algo1d.LocalLength(10) 
 
 # Define 2D algorithm and hypothesis
 algo2d = tetra.Triangle() 
 algo2d.LengthFromEdges() 
 
 # Define 3D algorithm and hypothesis
 algo3d = tetra.Tetrahedron()
 algo3d.MaxElementVolume(100) 
 
 # Compute the mesh
 tetra.Compute() 
 
 # Create a mesh group of all triangles generated on geom faces present in faces_group
 group = tetra.Group(faces_group)
 
 ###
 # Explore the mesh
 ###
 
 # Retrieve coordinates of nodes
 coordStr = ""
 for node in tetra.GetNodesId():
     x,y,z = tetra.GetNodeXYZ( node )
     coordStr += "%s (%s, %s, %s) " % ( node, x,y,z )
     pass
 
 # Retrieve nodal connectivity of triangles
 triaStr = ""
 for tria in tetra.GetElementsByType( SMESH.FACE ):
     nodes = tetra.GetElemNodes( tria )
     triaStr += "%s (%s, %s, %s) " % ( tria, nodes[0], nodes[1], nodes[2] )
 
 # Retrieve group contents
 groupStr = ""
 for group in tetra.GetGroups():
     ids   = group.GetIDs()
     name  = group.GetName()
     eType = group.GetType()
     groupStr += "'%s' %s: %s \n" % ( name, eType, ids )
 

Download this script

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