.. _ref_index_mesh_diagnostics:
****************
Mesh diagnostics
****************
===========================
Mesh statistics and quality
===========================
You can use a set of quality metrics to measure the mesh quality. The :class:`SurfaceSearch <ansys.meshing.prime.SurfaceSearch>`
and :class:`VolumeSearch <ansys.meshing.prime.VolumeSearch>` classes allow you to verify surface and volume mesh quality, respectively.
-------------------
Connectivity checks
-------------------
Surface diagnostics are important prior to generating a volume mesh. You can get a surface diagnostic summary by using
the :func:`SurfaceSearch.get_surface_diagnostic_summary() <ansys.meshing.prime.SurfaceSearch.get_surface_diagnostic_summary>`
method. The :class:`SurfaceDiagnosticSummaryParams <ansys.meshing.prime.SurfaceDiagnosticSummaryParams>` class provides for
diagnosing surface connectivity for the given scope and controls:
* Duplicate faces
* Free face edges
* Multi face edges
* Self intersections
This code determines if a wrap surface is closed:
.. code-block:: python
# Check if wrap surface is closed
scope = prime.ScopeDefinition(model=model, part_expression="wrap")
diag = prime.SurfaceSearch(model)
diag_params = prime.SurfaceDiagnosticSummaryParams(
model,
scope=scope,
compute_duplicate_faces=True,
compute_free_edges=True,
compute_multi_edges=True,
compute_self_intersections=True,
)
diag_res = diag.get_surface_diagnostic_summary(diag_params)
This code prints the results of the surface diagnostic summary:
.. code-block:: pycon
>>> print("Number of duplicate faces : ", diag_res.n_duplicate_faces)
>>> print("Number of free edges : ", diag_res.n_free_edges)
>>> print("Number of multi edges : ", diag_res.n_multi_edges)
>>> print("Number of self intersections : ", diag_res.n_self_intersections)
Number of duplicate faces : 0
Number of free edges : 0
Number of multi edges : 0
Number of self intersections : 0
------------
Face metrics
------------
The :class:`FaceQualityMeasure <ansys.meshing.prime.FaceQualityMeasure>` class offers various types
of measures to verify face quality metrics.
* The :attr:`SKEWNESS <ansys.meshing.prime.FaceQualityMeasure.SKEWNESS>` metric ranges between 0 (ideal) and 1 (worst).
* The :attr:`ASPECTRATIO <ansys.meshing.prime.FaceQualityMeasure.ASPECTRATIO>` metric is greater than 1. The smaller
the aspect ratio, the higher the quality of an element.
* The :attr:`ELEMENTQUALITY <ansys.meshing.prime.FaceQualityMeasure.ELEMENTQUALITY>` metric ranges between
0 (worst) and 1 (ideal).
This code gets face quality measures:
.. code-block:: python
face_quality_measures = prime.FaceQualityMeasure.SKEWNESS
quality = prime.SurfaceSearch(model)
quality_params = prime.SurfaceQualitySummaryParams(
model=model,
scope=prime.ScopeDefinition(model=model, part_expression="wrap"),
face_quality_measures=[face_quality_measures],
quality_limit=[0.9],
)
qual_summary_res = quality.get_surface_quality_summary(quality_params)
This code prints face quality summary results:
.. code-block:: pycon
>>> print("Maximum surface skewness : ", qual_summary_res.quality_results[0].max_quality)
>>> print("Number of faces above limit : ", qual_summary_res.quality_results[0].n_found)
Maximum surface skewness : 0.862375
Number of faces above limit : 0
------------
Cell metrics
------------
The :class:`CellQualityMeasure <ansys.meshing.prime.CellQualityMeasure>` class offers various types
of measures to verify cell quality metrics.
* The :attr:`SKEWNESS <ansys.meshing.prime.CellQualityMeasure.SKEWNESS>` metric ranges between
0 (ideal) and 1 (worst).
* The :attr:`ASPECTRATIO <ansys.meshing.prime.CellQualityMeasure.ASPECTRATIO>` metric
is greater than 1. The smaller the aspect ratio, the higher the quality of an element.
* The :attr:`FLUENTASPECTRATIO <ansys.meshing.prime.CellQualityMeasure.FLUENTASPECTRATIO>` metric
is greater than 1. The smaller the Fluent aspect ratio, the higher the quality of an element.
* The :attr:`ELEMENTQUALITY <ansys.meshing.prime.CellQualityMeasure.ELEMENTQUALITY>` metric ranges
between 0 (worst) and 1 (ideal).
This code gets cell quality measures:
.. code-block:: python
cell_quality_measures = prime.CellQualityMeasure.SKEWNESS
quality = prime.VolumeSearch(model)
quality_params = prime.VolumeQualitySummaryParams(
model=model,
scope=prime.ScopeDefinition(model=model, part_expression="wrap"),
cell_quality_measures=[cell_quality_measures],
quality_limit=[0.95],
)
qual_summary_res = quality.get_volume_quality_summary(quality_params)
This code prints cell quality summary results:
.. code-block:: pycon
>>> print("Maximum skewness : ", qual_summary_res.quality_results_part[0].max_quality)
>>> print(
... "Number of cells above limit : ", qual_summary_res.quality_results_part[0].n_found
... )
Maximum skewness : 0.948388
Number of cells above limit : 0
-----------
Mesh counts
-----------
The :func:`Part.get_summary() <ansys.meshing.prime.Part.get_summary>` method provides the
number of nodes, faces, or cells after meshing with the given parameters.
This code gets mesh counts:
.. code-block:: python
part_summary_res = part.get_summary(
prime.PartSummaryParams(model=model, print_id=False, print_mesh=True)
)
This code prints mesh counts:
.. code-block:: pycon
>>> print("Number of tri faces : ", part_summary_res.n_tri_faces)
>>> print("Number of tet cells : ", part_summary_res.n_tet_cells)
>>> print("Number of poly cells : ", part_summary_res.n_poly_cells)
>>> print("Total number of cells : ", part_summary_res.n_cells)
Number of tri faces : 49430
Number of tet cells : 254669
Number of poly cells : 82760
Total number of cells : 337429
================
Mesh improvement
================
When the metrics show that the mesh quality is low, the :class:`VolumeMeshTool <ansys.meshing.prime.VolumeMeshTool>`
class provides various volume mesh improvement algorithms for improving the mesh.
--------------
Auto node move
--------------
You can improve volume mesh by auto node move using the
:func:`VolumeMeshTool.improve_by_auto_node_move() <ansys.meshing.prime.VolumeMeshTool.improve_by_auto_node_move>`
method with given parameters. In addition, you can verify the mesh using the
:func:`VolumeMeshTool.check_mesh() <ansys.meshing.prime.VolumeMeshTool.check_mesh>` method.
This code improves and checks the volume mesh:
.. code-block:: python
# Auto node move
perform_anm = prime.VolumeMeshTool(model=model)
anm_params = prime.AutoNodeMoveParams(
model=model,
quality_measure=prime.CellQualityMeasure.SKEWNESS,
target_quality=0.95,
dihedral_angle=90,
n_iterations_per_node=50,
restrict_boundary_nodes_along_surface=True,
n_attempts=10,
)
perform_anm.improve_by_auto_node_move(
part_id=part.id,
cell_zonelets=part.get_cell_zonelets(),
boundary_zonelets=part.get_face_zonelets(),
params=anm_params,
)
# Mesh checking
vtool = prime.VolumeMeshTool(model=model)
res = vtool.check_mesh(part_id=part.id, params=prime.CheckMeshParams(model=model))
This code prints the results of checking mesh operation:
.. code-block:: pycon
>>> print("Non positive volumes:", result.has_non_positive_volumes)
>>> print("Non positive areas:", result.has_non_positive_areas)
>>> print("Invalid shape:", result.has_invalid_shape)
>>> print("Left handed faces:", result.has_left_handed_faces)
Non positive volumes : False
Non positive areas : False
Invalid shape : False
Left handed faces : False