feat(invdes): FXC-4605 added priority attribute to TopologyDesignRegion

Author: mahlau-flex

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Added
+- Added priority attribute to `TopologyDesignRegion` to enable manual control of overlapping structures.
 
 ### Changed
 

tests/test_plugins/test_invdes.py

@@ -156,6 +156,19 @@ def test_region_inf_size():
     _ = region.to_structure(params_0_inf)
 
 
+def test_region_priority():
+    region = make_design_region()
+
+    # Test default priority (None)
+    structure_default = region.to_structure(region.params_zeros)
+    assert structure_default.priority is None
+
+    # Test explicit priority value
+    region = region.updated_copy(priority=1)
+    structure = region.to_structure(region.params_zeros)
+    assert structure.priority == 1
+
+
 def post_process_fn(sim_data: td.SimulationData, **kwargs) -> float:
     """Define a post-processing function with extra kwargs (recommended)."""
     intensity = sim_data.get_intensity(MNT_NAME1)

tidy3d/plugins/invdes/region.py

@@ -179,6 +179,16 @@ class TopologyDesignRegion(DesignRegion):
         "Supplying ``False`` will completely leave out the override structure.",
     )
 
+    priority: int = pd.Field(
+        None,
+        title="Priority",
+        description="Priority of the structure applied in structure overlapping region. "
+        "The material property in the overlapping region is dictated by the structure "
+        "of higher priority. For structures of equal priority, "
+        "the structure added later to the structure list takes precedence. When `priority` is None, "
+        "the value is automatically assigned based on `structure_priority_mode` in the `Simulation`.",
+    )
+
     def _validate_eps_values(self) -> None:
         """Validate the epsilon values by evaluating the transformations."""
         try:
@@ -329,7 +339,7 @@ def to_structure(self, params: anp.ndarray) -> td.Structure:
         eps_values = self.eps_values(params)
         eps_data_array = td.SpatialDataArray(eps_values, coords=coords)
         medium = td.CustomMedium(permittivity=eps_data_array)
-        return td.Structure(geometry=self.geometry, medium=medium)
+        return td.Structure(geometry=self.geometry, medium=medium, priority=self.priority)
 
     @property
     def _override_structure_dl(self) -> float: