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# Mesh diagnostics
Last update: 02.04.2026
## Mesh statistics and quality
You can use a set of quality metrics to measure the mesh quality. The [`SurfaceSearch`](../api/_autosummary/ansys.meshing.prime.SurfaceSearch.md#ansys.meshing.prime.SurfaceSearch)and [`VolumeSearch`](../api/_autosummary/ansys.meshing.prime.VolumeSearch.md#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 [`SurfaceSearch.get_surface_diagnostic_summary()`](../api/_autosummary/ansys.meshing.prime.SurfaceSearch.get_surface_diagnostic_summary.md#ansys.meshing.prime.SurfaceSearch.get_surface_diagnostic_summary)method. The [`SurfaceDiagnosticSummaryParams`](../api/_autosummary/ansys.meshing.prime.SurfaceDiagnosticSummaryParams.md#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:
```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:
```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 [`FaceQualityMeasure`](../api/_autosummary/ansys.meshing.prime.FaceQualityMeasure.md#ansys.meshing.prime.FaceQualityMeasure) class offers various types of measures to verify face quality metrics.
- The [`SKEWNESS`](../api/_autosummary/ansys.meshing.prime.FaceQualityMeasure.SKEWNESS.md#ansys.meshing.prime.FaceQualityMeasure.SKEWNESS) metric ranges between 0 (ideal) and 1 (worst).
- The [`ASPECTRATIO`](../api/_autosummary/ansys.meshing.prime.FaceQualityMeasure.ASPECTRATIO.md#ansys.meshing.prime.FaceQualityMeasure.ASPECTRATIO) metric is greater than 1. The smaller the aspect ratio, the higher the quality of an element.
- The [`ELEMENTQUALITY`](../api/_autosummary/ansys.meshing.prime.FaceQualityMeasure.ELEMENTQUALITY.md#ansys.meshing.prime.FaceQualityMeasure.ELEMENTQUALITY) metric ranges between 0 (worst) and 1 (ideal).
This code gets face quality measures:
```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:
```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 [`CellQualityMeasure`](../api/_autosummary/ansys.meshing.prime.CellQualityMeasure.md#ansys.meshing.prime.CellQualityMeasure) class offers various types of measures to verify cell quality metrics.
- The [`SKEWNESS`](../api/_autosummary/ansys.meshing.prime.CellQualityMeasure.SKEWNESS.md#ansys.meshing.prime.CellQualityMeasure.SKEWNESS) metric ranges between 0 (ideal) and 1 (worst).
- The [`ASPECTRATIO`](../api/_autosummary/ansys.meshing.prime.CellQualityMeasure.ASPECTRATIO.md#ansys.meshing.prime.CellQualityMeasure.ASPECTRATIO) metric is greater than 1. The smaller the aspect ratio, the higher the quality of an element.
- The [`FLUENTASPECTRATIO`](../api/_autosummary/ansys.meshing.prime.CellQualityMeasure.FLUENTASPECTRATIO.md#ansys.meshing.prime.CellQualityMeasure.FLUENTASPECTRATIO) metric is greater than 1. The smaller the Fluent aspect ratio, the higher the quality of an element.
- The [`ELEMENTQUALITY`](../api/_autosummary/ansys.meshing.prime.CellQualityMeasure.ELEMENTQUALITY.md#ansys.meshing.prime.CellQualityMeasure.ELEMENTQUALITY) metric ranges between 0 (worst) and 1 (ideal).
This code gets cell quality measures:
```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:
```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 [`Part.get_summary()`](../api/_autosummary/ansys.meshing.prime.Part.get_summary.md#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:
```python
part_summary_res = part.get_summary(
prime.PartSummaryParams(model=model, print_id=False, print_mesh=True)
)
```
This code prints mesh counts:
```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 [`VolumeMeshTool`](../api/_autosummary/ansys.meshing.prime.VolumeMeshTool.md#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 [`VolumeMeshTool.improve_by_auto_node_move()`](../api/_autosummary/ansys.meshing.prime.VolumeMeshTool.improve_by_auto_node_move.md#ansys.meshing.prime.VolumeMeshTool.improve_by_auto_node_move)method with given parameters. In addition, you can verify the mesh using the [`VolumeMeshTool.check_mesh()`](../api/_autosummary/ansys.meshing.prime.VolumeMeshTool.check_mesh.md#ansys.meshing.prime.VolumeMeshTool.check_mesh) method.
This code improves and checks the volume mesh:
```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:
```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
```