Tetrahedralize¶

Description¶

Subdivide 3D mesh cells into tetrahedra, or 2D mesh cells into triangles.

When the base contains polygons or polyhedra, VTK must be installed.

Parameters¶

base: Base
The input base to be tetrahedralized.

coordinates: list(str)
The variable names that define the set of coordinates. If no value is given, the default coordinate system of the base is used. Only useful if the base contains polyhedra or polygons.

Preconditions¶

The input base may be structured or unstructured. It remains unchanged during treatment. If it is structured, then it is first deepcopied, and the copy is made unstructured. So, the memory footprint will be roughly three times the initial one.

When the base contains polyhedra, the cells must be convex and the faces planar. Generally, these conditions are not fulfilled because of numerical issues, but it is often not a problem.

Postconditions¶

A new unstructured base is returned.

Warning

The extensive variables that are at cell centers in the input base are interpolated to order 0. It is likely that they are not coherent with the mesh of the output base. (e.g. volume, surface, and normal vector)

Example¶

import antares
myt = antares.Treatment('tetrahedralize')
myt['base'] = base
tetra_base = myt.execute()

** References**

How to subdivide pyramids, prisms and hexaedra into tetrahedra, J. Dompierre, P. Labbe, M-G. Vallet, R. Camarero, Rapport CERCA R99-78, 24 august 1999 Conference paper from the 8th International Meshing Roundtable, Lake Tahoe, Cal., 10-13/10/1999

Main functions¶

class antares.treatment.TreatmentTetrahedralize.TreatmentTetrahedralize¶

Treatment used to build a tetrahedralization of a mesh.

Principle: a quadrilateral face is subdivided into two triangular faces by the diagonal issued from the from the smallest vertices of the face.

execute()¶

Build the tetrahedralization of a mesh.

Returns:: a base with tetrahedral elements.
Return type:: Base

Example¶

"""
This example shows how to transform all elements of a base in tetrahedra.
"""
import os

from antares import Reader, Treatment, Writer

# ------------------
# Reading the files
# ------------------
r = Reader('hdf_avbp')
r['filename'] = os.path.join('..', 'data', 'SECTOR', 'hybrid_sector.mesh.h5')
r['shared'] = True
base = r.read()
r = Reader('hdf_avbp')
r['base'] = base
r['filename'] = os.path.join('..', 'data', 'SECTOR', 'hybrid_sector.sol.h5')
r.read()

treatment = Treatment('tetrahedralize')
treatment['base'] = base
result = treatment.execute()

result.show()
# ------------------
# Reading the files
# ------------------
reader = Reader('bin_tp')
reader['filename'] = os.path.join('..', 'data', 'ROTOR37', 'GENERIC', 'flow_<zone>_ite<instant>.dat')
base = reader.read()

treatment = Treatment('tetrahedralize')
treatment['base'] = base
result = treatment.execute()

result.show()

r = Reader('bin_tp')
r['filename'] = os.path.join('..', 'data', 'ROTOR37', 'ELSA_CASE', 'MESH', 'mesh_<zone>.dat')
r['zone_prefix'] = 'Block'
r['topology_file'] = os.path.join('..', 'data', 'ROTOR37', 'ELSA_CASE', 'script_topo.py')
r['shared'] = True
base = r.read()

r = Reader('bin_tp')
r['base'] = base
r['filename'] = os.path.join('..', 'data', 'ROTOR37', 'ELSA_CASE', 'FLOW', 'flow_<zone>.dat')
r['zone_prefix'] = 'Block'
r['location'] = 'cell'
base = r.read()

treatment = Treatment('tetrahedralize')
treatment['base'] = base
result = treatment.execute()

result.show()

—

Utilitary class and methods¶

class antares.treatment.TreatmentTetrahedralize.Tetrahedralizer(dim, connectivity)¶

Build the tetrahedralisation of a mesh.

interpolate(value, location)¶

Returns:: interpolated value for the tetrahedral mesh.

interpolate_cell(value)¶

Returns:: interpolated cells values (order 0)

interpolate_node(value)¶

Returns:: node values

property connectivity¶

Returns:: tetrahedral connectivity.
Return type:: CustomDict

property src_cell¶

Returns:: mapping between new cells and parent cells.

antares.utils.geomcut.tetrahedralizer.tri2tri(tri_conn)¶: Return a dummy subdivision for triangles.

antares.utils.geomcut.tetrahedralizer.qua2tri(qua_conn)¶

Subdivide quadrilateral cells into triangles.

Parameters:

qua_conn – a quadrilateral cell-based connectivity

Returns:

out_conn, src_cell

out_conn: the resulting triangular connectivity.
src_cell: the cell from which the new cell was generated.

antares.utils.geomcut.tetrahedralizer.tet2tet(tet_conn)¶: Return a dummy subdivision for tetrahedra.

antares.utils.geomcut.tetrahedralizer.pyr2tet(pyr_conn)¶

Subdivide pyramidal cells into tetrahedra.

Parameters:

pyr_conn – a pyramidal cell-based connectivity.

Returns:

out_conn, src_cell

out_conn: the resulting tetrahedral connectivity.
src_cell: the cell from which the new cell was generated.

antares.utils.geomcut.tetrahedralizer.pri2tet(pri_conn)¶

Subdivide prismatic cells into tetrahedra.

Parameters:

pri_conn – a prismatic cell-based connectivity.

Returns:

out_conn, src_cell

out_conn: the resulting tetrahedral connectivity.
src_cell: the cell from which the new cell was generated.

antares.utils.geomcut.tetrahedralizer.hex2tet(hex_conn)¶

Subdivide hexahedral cells into tetrahedra.

Parameters:

hex_conn – a hexahedral cell-based connectivity.

Returns:

out_conn, src_cell

out_conn: the resulting tetrahedral connectivity.
src_cell: the cell from which the new cell was generated.