tidy3d.MeshOverrideStructure

class MeshOverrideStructure

Bases: AbstractStructure

Defines an object that is only used in the process of generating the mesh.

Parameters:

• geometry (Union[Box, Transformed, ClipOperation, GeometryGroup, GeometryArray, Sphere, Cylinder, PolySlab, ComplexPolySlabBase, TriangleMesh]) – Defines geometric properties of the structure.

• name (Optional[str] = None) – Optional name for the structure.

• background_permittivity (Optional[float] = None) – DEPRECATED: Use Structure.background_medium. Relative permittivity used for the background of this structure when performing shape optimization with autograd.

• background_medium (Optional[Union[MultiPhysicsMedium, Medium, AnisotropicMedium, PECMedium, PMCMedium, PoleResidue, Sellmeier, Lorentz, Debye, Drude, FullyAnisotropicMedium, CustomMedium, CustomPoleResidue, CustomSellmeier, CustomLorentz, CustomDebye, CustomDrude, CustomAnisotropicMedium, PerturbationMedium, PerturbationPoleResidue, LossyMetalMedium, Medium2D, AnisotropicMediumFromMedium2D, FluidSpec, SolidSpec, SolidMedium, FluidMedium, ChargeConductorMedium, ChargeInsulatorMedium, SemiconductorMedium]] = None) – Medium used for the background of this structure when performing shape optimization with autograd. This is required when the structure is embedded in another structure as autograd will use the permittivity of the Simulation by default to compute the shape derivatives.

• priority (int = 0) – Priority of the structure applied in mesh override structure overlapping region. The priority of internal override structures is -1.

• dl (tuple[Optional[PositiveFloat], Optional[PositiveFloat], Optional[PositiveFloat]]) – [units = um]. Grid size along x, y, z directions.

• enforce (bool = False) – If True, enforce the grid size setup inside the structure even if the structure is inside a structure of smaller grid size. In the intersection region of multiple structures of enforce=True, grid size is decided by the last added structure of enforce=True.

• shadow (bool = True) – In structure intersection region, grid size is decided by the latter added structure in the structure list when shadow=True; or the structure of smaller grid size when shadow=False. If shadow=False, and the structure doesn’t refine the mesh, grid snapping to the bounding box of the structure is disabled.

• drop_outside_sim (bool = True) – If True, structure outside the simulation domain is dropped; if False, structure takes effect along the dimensions where the projections of the structure and that of the simulation domain overlap.

Notes

A MeshOverrideStructure is a combination of geometry Geometry, grid size along x, y, z directions, and a boolean on whether the override will be enforced.

Example

>>> from tidy3d import Box
>>> box = Box(center=(0,0,1), size=(2, 2, 2))
>>> struct_override = MeshOverrideStructure(geometry=box, dl=(0.1,0.2,0.3), name='override_box')

Attributes

dl
priority
enforce
shadow
drop_outside_sim
geometry
name
background_permittivity
background_medium

dl

priority

enforce

shadow

drop_outside_sim