[Hotfix Main]: [SNAPPY] Custom logic to calculate min_vol quality metric

flow360/component/simulation/meshing_param/snappy/snappy_specs.py

@@ -54,11 +54,12 @@ class QualityMetrics(Flow360BaseModel):
         alias="max_concave",
         description="Maximum cell concavity. Set to False to disable this metric.",
     )
-    min_pyramid_cell_volume: Union[float, Literal[False]] = pd.Field(
-        default=1e-15,
+    min_pyramid_cell_volume: Optional[Union[float, Literal[False]]] = pd.Field(
+        default=None,
         alias="min_vol",
         description="Minimum cell pyramid volume [mesh_unit³]. "
-        + "Set to False to disable this metric (uses -1e30 internally).",
+        + "Set to False to disable this metric (uses -1e30 internally). "
+        + "Defaults to (effective_min_spacing³) * 1e-10 when not specified.",
     )
     min_tetrahedron_quality: Union[float, Literal[False]] = pd.Field(
         default=1e-9,

flow360/component/simulation/translator/surface_meshing_translator.py

@@ -287,6 +287,55 @@ def apply_UniformRefinement_w_snappy(
         translated["geometry"]["refinementVolumes"].append(volume_body)
 
 
+def _none_tolerant_min(current, candidate):
+    """Return the smaller of two spacing quantities, comparing by raw value."""
+    if candidate is not None and candidate < current:
+        return candidate
+    return current
+
+
+def _get_effective_min_spacing(input_params, spacing_system: OctreeSpacing):
+    """
+    Get the effective minimum spacing across all refinements,
+    taking proximity_spacing (gap spacing reduction), edge spacings, and
+    projected volume refinements into account.
+    The result is cast to the nearest lower spacing in the octree series.
+    """
+    surface_meshing_params = input_params.meshing.surface_meshing
+    min_spacing = surface_meshing_params.defaults.min_spacing
+
+    for refinement in surface_meshing_params.refinements or []:
+        if isinstance(refinement, (snappy.BodyRefinement, snappy.RegionRefinement)):
+            min_spacing = _none_tolerant_min(min_spacing, refinement.min_spacing)
+            min_spacing = _none_tolerant_min(min_spacing, refinement.proximity_spacing)
+        elif (
+            isinstance(refinement, snappy.SurfaceEdgeRefinement) and refinement.spacing is not None
+        ):
+            edge_spacing = (
+                refinement.spacing[0]
+                if isinstance(refinement.spacing, unyt_array)
+                and isinstance(refinement.distances, unyt_array)
+                and len(refinement.spacing) > 0
+                else refinement.spacing
+            )
+            min_spacing = _none_tolerant_min(min_spacing, edge_spacing)
+        elif isinstance(refinement, UniformRefinement):
+            min_spacing = _none_tolerant_min(min_spacing, refinement.spacing)
+
+    # Also consider projected volume meshing refinements
+    if input_params.meshing.volume_meshing is not None:
+        for refinement in input_params.meshing.volume_meshing.refinements:
+            if isinstance(refinement, UniformRefinement) and refinement.project_to_surface in [
+                True,
+                None,
+            ]:
+                min_spacing = _none_tolerant_min(min_spacing, refinement.spacing)
+
+    # Cast to the nearest lower spacing in the octree series
+    level = spacing_system.to_level(min_spacing)[0]
+    return spacing_system[level].value.item()
+
+
 # pylint: disable=too-many-branches,too-many-statements,too-many-locals
 def snappy_mesher_json(input_params: SimulationParams):
     """
@@ -412,9 +461,13 @@ def snappy_mesher_json(input_params: SimulationParams):
                 else 180
             ),
             "minVol": (
-                quality_settings.min_pyramid_cell_volume
-                if quality_settings.min_pyramid_cell_volume
-                else -1e30
+                -1e30
+                if quality_settings.min_pyramid_cell_volume is False
+                else (
+                    quality_settings.min_pyramid_cell_volume
+                    if quality_settings.min_pyramid_cell_volume is not None
+                    else (1e-10 * (_get_effective_min_spacing(input_params, spacing_system) ** 3))
+                )
             ),
             "minTetQuality": (
                 quality_settings.min_tetrahedron_quality

tests/simulation/translator/ref/surface_meshing/default_snappy.json

@@ -86,7 +86,7 @@
             "maxBoundarySkewness": 20,
             "maxInternalSkewness": 50,
             "maxConcave": 50,
-            "minVol": 1e-15,
+            "minVol": 8e-10,
             "minTetQuality": 1e-9,
             "minArea": 1e-12,
             "minTwist": -2,

tests/simulation/translator/ref/surface_meshing/snappy_basic_refinements.json

@@ -179,7 +179,7 @@
             "maxBoundarySkewness": 20,
             "maxInternalSkewness": 50,
             "maxConcave": 50,
-            "minVol": 1e-15,
+            "minVol": 1.308441162109375e-13,
             "minTetQuality": 1e-9,
             "minArea": 1e-12,
             "minTwist": -2,

tests/simulation/translator/ref/surface_meshing/snappy_coupled_refinements.json

@@ -103,7 +103,7 @@
             "maxBoundarySkewness": 20,
             "maxInternalSkewness": 50,
             "maxConcave": 50,
-            "minVol": 1e-15,
+            "minVol": 1.953125e-10,
             "minTetQuality": 1e-9,
             "minArea": 1e-12,
             "minTwist": -2,

tests/simulation/translator/ref/surface_meshing/snappy_no_regions.json

@@ -59,7 +59,7 @@
             "maxBoundarySkewness": 20,
             "maxInternalSkewness": 50,
             "maxConcave": 50,
-            "minVol": 1e-15,
+            "minVol": 1.953125e-13,
             "minTetQuality": 1e-9,
             "minArea": 1e-12,
             "minTwist": -2,

tests/simulation/translator/ref/surface_meshing/snappy_refinements_multiple_regions.json

@@ -129,7 +129,7 @@
             "maxBoundarySkewness": 20,
             "maxInternalSkewness": 50,
             "maxConcave": 50,
-            "minVol": 1e-15,
+            "minVol": 2.7e-09,
             "minTetQuality": 1e-9,
             "minArea": 1e-12,
             "minTwist": -2,

tests/simulation/translator/test_surface_meshing_translator.py

@@ -1046,7 +1046,7 @@ def test_rotor_surface_mesh(get_rotor_geometry, rotor_surface_mesh):
 
 def test_snappy_default(get_snappy_geometry, snappy_all_defaults):
     _translate_and_compare(
-        snappy_all_defaults, get_snappy_geometry.mesh_unit, "default_snappy.json"
+        snappy_all_defaults, get_snappy_geometry.mesh_unit, "default_snappy.json", atol=1e-6
     )
 
 
@@ -1073,11 +1073,14 @@ def test_snappy_multiple_regions(get_snappy_geometry, snappy_refinements_multipl
         snappy_refinements_multiple_regions,
         get_snappy_geometry.mesh_unit,
         "snappy_refinements_multiple_regions.json",
+        atol=1e-6,
     )
 
 
 def test_snappy_settings(get_snappy_geometry, snappy_settings):
-    _translate_and_compare(snappy_settings, get_snappy_geometry.mesh_unit, "snappy_settings.json")
+    _translate_and_compare(
+        snappy_settings, get_snappy_geometry.mesh_unit, "snappy_settings.json", atol=1e-6
+    )
 
 
 def test_snappy_settings_off_position(get_snappy_geometry, snappy_settings_off_position):
@@ -1088,7 +1091,10 @@ def test_snappy_settings_off_position(get_snappy_geometry, snappy_settings_off_p
 
 def test_snappy_no_refinements(get_snappy_geometry, snappy_refinements_no_regions):
     _translate_and_compare(
-        snappy_refinements_no_regions, get_snappy_geometry.mesh_unit, "snappy_no_regions.json"
+        snappy_refinements_no_regions,
+        get_snappy_geometry.mesh_unit,
+        "snappy_no_regions.json",
+        atol=1e-6,
     )