[SNAPPY] Enable only selected shapes of UniformRefinement (#1846)

Co-authored-by: Ben <106089368+benflexcompute@users.noreply.github.com>
Co-authored-by: benflexcompute <ben@flexcompute.com>

Author: piotrkluba

flow360/component/simulation/meshing_param/meshing_validators.py

@@ -0,0 +1,30 @@
+"""Shared validation helpers for meshing parameters."""
+
+import flow360.component.simulation.units as u
+from flow360.component.simulation.meshing_param.volume_params import UniformRefinement
+from flow360.component.simulation.primitives import Box, Cylinder
+
+
+def validate_snappy_uniform_refinement_entities(refinement: UniformRefinement):
+    """Validate that a UniformRefinement's entities are compatible with snappyHexMesh.
+
+    Raises ValueError if any Box has a non-axis-aligned rotation or any Cylinder is hollow.
+    """
+    # pylint: disable=no-member
+    for entity in refinement.entities.stored_entities:
+        if (
+            isinstance(entity, Box)
+            and entity.angle_of_rotation.to("deg") % (360 * u.deg) != 0 * u.deg
+        ):
+            raise ValueError(
+                "UniformRefinement for snappy accepts only Boxes with axes aligned"
+                + " with the global coordinate system (angle_of_rotation=0)."
+            )
+        if (
+            isinstance(entity, Cylinder)
+            and entity.inner_radius is not None
+            and entity.inner_radius.to("m") != 0 * u.m
+        ):
+            raise ValueError(
+                "UniformRefinement for snappy accepts only full cylinders (where inner_radius = 0)."
+            )

flow360/component/simulation/meshing_param/params.py

@@ -22,6 +22,9 @@
     MeshingDefaults,
     VolumeMeshingDefaults,
 )
+from flow360.component.simulation.meshing_param.meshing_validators import (
+    validate_snappy_uniform_refinement_entities,
+)
 from flow360.component.simulation.meshing_param.volume_params import (
     AutomatedFarfield,
     AxisymmetricRefinement,
@@ -589,6 +592,19 @@ def _check_sizing_against_octree_series(self, param_info: ParamsValidationInfo):
 
         return self
 
+    @contextual_model_validator(mode="after")
+    def _check_snappy_uniform_refinement_entities(self, param_info: ParamsValidationInfo):
+        """Validate projected UniformRefinement entities are compatible with snappyHexMesh."""
+        if not param_info.use_snappy:
+            return self
+        for refinement in self.refinements:  # pylint: disable=not-an-iterable
+            if (
+                isinstance(refinement, UniformRefinement)
+                and refinement.project_to_surface is not False
+            ):
+                validate_snappy_uniform_refinement_entities(refinement)
+        return self
+
 
 SurfaceMeshingParams = Annotated[
     Union[snappy.SurfaceMeshingParams], pd.Field(discriminator="type_name")

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

@@ -4,9 +4,11 @@
 
 import pydantic as pd
 
-import flow360.component.simulation.units as u
 from flow360.component.simulation.framework.base_model import Flow360BaseModel
 from flow360.component.simulation.meshing_param.meshing_specs import OctreeSpacing
+from flow360.component.simulation.meshing_param.meshing_validators import (
+    validate_snappy_uniform_refinement_entities,
+)
 from flow360.component.simulation.meshing_param.snappy.snappy_mesh_refinements import (
     BodyRefinement,
     RegionRefinement,
@@ -22,7 +24,6 @@
     SurfaceMeshingDefaults,
 )
 from flow360.component.simulation.meshing_param.volume_params import UniformRefinement
-from flow360.component.simulation.primitives import Box, Cylinder
 from flow360.component.simulation.unit_system import LengthType
 from flow360.component.simulation.validation.validation_context import (
     ParamsValidationInfo,
@@ -124,20 +125,7 @@ def _check_uniform_refinement_entities(self):
             return self
         for refinement in self.refinements:
             if isinstance(refinement, UniformRefinement):
-                # No expansion needed since we only allow Draft entities here.
-                for entity in refinement.entities.stored_entities:
-                    if (
-                        isinstance(entity, Box)
-                        and entity.angle_of_rotation.to("deg") % (360 * u.deg) != 0 * u.deg
-                    ):
-                        raise ValueError(
-                            "UniformRefinement for snappy accepts only Boxes with axes aligned"
-                            + " with the global coordinate system (angle_of_rotation=0)."
-                        )
-                    if isinstance(entity, Cylinder) and entity.inner_radius.to("m") != 0 * u.m:
-                        raise ValueError(
-                            "UniformRefinement for snappy accepts only full cylinders (where inner_radius = 0)."
-                        )
+                validate_snappy_uniform_refinement_entities(refinement)
 
         return self
 

flow360/component/simulation/meshing_param/volume_params.py

@@ -103,6 +103,26 @@ def check_entities_used_with_beta_mesher(cls, values, param_info: ParamsValidati
 
         return values
 
+    @contextual_field_validator("entities", mode="after")
+    @classmethod
+    def check_entities_used_with_snappy(cls, values, param_info: ParamsValidationInfo):
+        """Check that only Box, Cylinder, and Sphere entities are used with snappyHexMesh."""
+
+        if values is None:
+            return values
+        if not param_info.use_snappy:
+            return values
+
+        expanded = param_info.expand_entity_list(values)
+        for entity in expanded:
+            if not isinstance(entity, (Box, Cylinder, Sphere)):
+                raise ValueError(
+                    f"`{type(entity).__name__}` entity for `UniformRefinement` is not supported "
+                    "with snappyHexMesh. Only `Box`, `Cylinder`, and `Sphere` are allowed."
+                )
+
+        return values
+
     @contextual_model_validator(mode="after")
     def check_project_to_surface_with_snappy(self, param_info: ParamsValidationInfo):
         """Check that project_to_surface is used only with snappy."""

tests/simulation/params/meshing_validation/test_meshing_param_validation.py

@@ -69,6 +69,10 @@
 beta_mesher_context.is_beta_mesher = True
 beta_mesher_context.project_length_unit = "mm"
 
+snappy_context = ParamsValidationInfo({}, [])
+snappy_context.use_snappy = True
+snappy_context.is_beta_mesher = True
+
 
 def test_structured_box_only_in_beta_mesher():
     # raises when beta mesher is off
@@ -870,7 +874,20 @@ def test_sphere_in_uniform_refinement():
                 ],
             )
 
-    # raises without beta mesher
+    # also allowed with snappy
+    with ValidationContext(VOLUME_MESH, snappy_context):
+        with CGS_unit_system:
+            sphere = Sphere(
+                name="s_snappy",
+                center=(0, 0, 0),
+                radius=1.0,
+            )
+            UniformRefinement(
+                entities=[sphere],
+                spacing=0.1,
+            )
+
+    # raises without beta mesher or snappy
     with pytest.raises(
         pd.ValidationError,
         match=r"`Sphere` entity for `UniformRefinement` is supported only with beta mesher",
@@ -888,6 +905,45 @@ def test_sphere_in_uniform_refinement():
                 )
 
 
+def test_uniform_refinement_snappy_entity_restrictions():
+    """With snappy, UniformRefinement only accepts Box, Cylinder, and Sphere entities."""
+    # Box, Cylinder, Sphere all allowed
+    with ValidationContext(VOLUME_MESH, snappy_context):
+        with CGS_unit_system:
+            UniformRefinement(
+                entities=[
+                    Box(center=(0, 0, 0), size=(1, 1, 1), name="box"),
+                    Cylinder(
+                        name="cyl",
+                        axis=(0, 0, 1),
+                        center=(0, 0, 0),
+                        height=1.0,
+                        outer_radius=0.5,
+                    ),
+                    Sphere(name="sph", center=(0, 0, 0), radius=1.0),
+                ],
+                spacing=0.1,
+            )
+
+    # AxisymmetricBody rejected with snappy
+    with pytest.raises(
+        pd.ValidationError,
+        match=r"`AxisymmetricBody` entity for `UniformRefinement` is not supported with snappyHexMesh",
+    ):
+        with ValidationContext(VOLUME_MESH, snappy_context):
+            with CGS_unit_system:
+                axisymmetric_body = AxisymmetricBody(
+                    name="axisymm",
+                    axis=(0, 0, 1),
+                    center=(0, 0, 0),
+                    profile_curve=[(-1, 0), (-1, 1), (1, 1), (1, 0)],
+                )
+                UniformRefinement(
+                    entities=[axisymmetric_body],
+                    spacing=0.1,
+                )
+
+
 def test_require_mesh_zones():
     with SI_unit_system:
         ModularMeshingWorkflow(