Fix corner filtering in LayerRefinementSpec

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 ### Fixed
+- Bug in `LayerRefinementSpec` that refines grids in the region outside the layer when one in-plane dimension has size infinity.
 
 ## [2.8.0] - 2025-03-04
 

tests/test_components/test_layerrefinement.py

@@ -101,18 +101,19 @@ def test_layerrefinement():
         assert layer.size[axis] == 1
         assert layer.size[(axis + 1) % 3] == td.inf
         assert layer.size[(axis + 2) % 3] == td.inf
-        assert layer._is_inplane_unbounded
+        assert not layer._is_inplane_bounded
 
     layer = LayerRefinementSpec.from_bounds(axis=axis, rmin=(0, 0, 0), rmax=(1, 2, 3))
     layer = LayerRefinementSpec.from_bounds(rmin=(0, 0, 0), rmax=(1, 2, 3))
     assert layer.axis == 0
     assert np.isclose(layer.length_axis, 1)
     assert np.isclose(layer.center_axis, 0.5)
-    assert not layer._is_inplane_unbounded
+    assert layer._is_inplane_bounded
 
     # from structures
     structures = [td.Structure(geometry=td.Box(size=(td.inf, 2, 3)), medium=td.Medium())]
     layer = LayerRefinementSpec.from_structures(structures)
+    assert layer._is_inplane_bounded
     assert layer.axis == 1
 
     with pytest.raises(pydantic.ValidationError):
@@ -134,6 +135,7 @@ def test_layerrefinement():
 def test_layerrefinement_inplane_inside():
     # inplane inside
     layer = LayerRefinementSpec.from_layer_bounds(axis=2, bounds=(0, 1))
+    assert not layer._is_inplane_bounded
     assert layer._inplane_inside([3e3, 4e4])
     layer = LayerRefinementSpec(axis=1, size=(1, 0, 1))
     assert layer._inplane_inside([0, 0])

tidy3d/components/grid/grid_spec.py

@@ -1226,9 +1226,11 @@ def center_axis(self) -> float:
         return self.center[self.axis]
 
     @cached_property
-    def _is_inplane_unbounded(self) -> bool:
-        """Whether the layer is unbounded in any of the inplane dimensions."""
-        return np.isinf(self.size[(self.axis + 1) % 3]) or np.isinf(self.size[(self.axis + 2) % 3])
+    def _is_inplane_bounded(self) -> bool:
+        """Whether the layer is bounded in at least one of the inplane dimensions."""
+        return np.isfinite(self.size[(self.axis + 1) % 3]) or np.isfinite(
+            self.size[(self.axis + 2) % 3]
+        )
 
     def _unpop_axis(self, ax_coord: float, plane_coord: Any) -> CoordinateOptional:
         """Combine coordinate along axis with identical coordinates on the plane tangential to the axis.
@@ -1321,14 +1323,14 @@ def _corners(self, structure_list: List[Structure]) -> List[CoordinateOptional]:
 
         # filter structures outside the layer
         structures_intersect = structure_list
-        if not self._is_inplane_unbounded:
+        if self._is_inplane_bounded:
             structures_intersect = [s for s in structure_list if self.intersects(s.geometry)]
         inplane_points = self.corner_finder.corners(
             self.axis, self.center_axis, structures_intersect
         )
 
         # filter corners outside the inplane bounds
-        if not self._is_inplane_unbounded:
+        if self._is_inplane_bounded:
             inplane_points = [point for point in inplane_points if self._inplane_inside(point)]
 
         # convert 2d points to 3d