v2.12.0.dev0

What's Changed

Added

• Added CornerFinderSpec.corner_rounding_collapse_extent so LayerRefinementSpec can recover sharp corners that pass the legacy angle threshold from small rounded or chamfered imported geometry.
• Added ImpedanceSpec to support complex-valued LumpedPort impedance. The impedance field now accepts either a plain real number (e.g. 50) or an ImpedanceSpec(impedance=..., frequency=...) for complex-valued loads. A complex impedance Z = R + jX is mapped to a series RL or RC load at the given measurement frequency, enabling reactive terminations in S-parameter simulations. Purely reactive loads (Re(Z) = 0) are not supported; Re(Z) must be strictly positive to ensure a stable FDTD pole.
• Added a dedicated PyTorch wrapper plugin documentation page under api/plugins/pytorch.
• Added autograd support for ClipOperation geometry derivatives, including union, difference, intersection, and symmetric_difference.
• Added the tidy3d mcp command for running the Tidy3D MCP server from the active Tidy3D environment.
• Added Palik_NoLoss material-fitter refits for the low-loss Palik ranges of GaAs, Ge, SiO2, and cSi, and Palik_LowLoss variants for the previous Palik fits of GaAs, Ge, InP, SiO2, and cSi.
• Added per-interface physical residual diagnostics for EME: incident-normalized squared tangential E/H field residuals, corresponding non-PML-aperture residuals, and the flux-weighted power conservation defect, stored on EMESimulationData.diagnostics when EMESimulation.eme_diagnostics=True.
• Added a progress keyword (default True) to EMESimulation.compute_overlaps, EMESimulation.propagate_from_overlaps, and EMESimulation.propagate that shows a per-phase rich progress bar on the logging console; pass progress=False to silence it.
• Accelerated charge solver support for the Masetti mobility model.
• DeviceCharacteristics.dc_convergence (new SteadyConvergenceData) flags per-bias Newton convergence and exposes the per-iteration residual trace, so callers can mask the I-V/C-V curves by the converged biases and inspect at which iteration each bias crossed the tolerance.
• Added support for explicit payment type, priority, and vGPU allocation settings when submitting component modeler batch tasks.

Changed

• WavePort and TerminalWavePort mesh refinement now interprets num_grid_cells as the cell count along the largest transverse dimension (the smaller dimension is aspect-ratio-scaled), with the default raised from 5 to 12. Two grid-snapping points are also emitted at opposite corners of the port plane.
• Changed the default autograd minimum_spacing_fraction from 0.01 to 0.001; set it back to 0.01 in your config to keep previous spacing behavior.
• UniformUnstructuredGrid.min_edges_per_circumference and min_edges_per_side now accept 0, which skips the corresponding local mesh-size contribution. A deprecation warning is emitted when either field is left at its default: the default will change to 0 in the next release. Set the fields explicitly to preserve the current behavior.
• Changed grid validation to raise a units error when UniformGrid.dl or generated AutoGrid / QuasiUniformGrid cell sizes are below 1e-6 um.
• Improved memory usage and runtime for autograd local far-field projections in the 3D paired approximate path used by Cartesian and k-space monitors with far_field_approx=True.
• Reduced peak memory usage when differentiating exact local field projections (far_field_approx=False).
• Increased default ChargeToleranceSpec.max_iters from 30 to 120; set it explicitly to keep the previous behavior.
• HeatChargeSimulation.use_accelerated_solver=False (selecting the CPU charge solver) is now validated at construction and raises a ValidationError on use_accelerated_solver for configurations the CPU solver cannot run: heat and conduction simulations (which always run on the GPU accelerated solver) and charge simulations using GPU-accelerated-only features such as MasettiMobility or SSAC at_voltages bias-point selection. The flag now defaults to True (was Optional defaulting to None) and continues to use the GPU accelerated charge solver.

Fixed

• Suppressed the Simulation structure-at-boundary warning for structures touching Periodic or BlochBoundary edges, while keeping the warning for other boundary types unless structure extrusion is enabled.
• Improved auto-generated API documentation for classes with computed default values (e.g. NedeljkovicSorefMashanovich), eliminating malformed Parameters sections and a long tail of other documentation build issues.
• Raise a validation error when an automatically added PEC frame (around a mode source with PECFrame or an internal absorber) overlaps the absorbing-boundary extrusion clipping region on any boundary with extrude_structures=True. To opt out on a side that legitimately needs the source / absorber to reach the boundary (e.g. a wave-port source that spans the lateral domain via symmetry), pass extrude_structures=False to the boundary — either through Boundary.pml / Boundary.stable_pml / Boundary.absorber (now exposed there) or by constructing Boundary(plus=td.PML(extrude_structures=False), minus=td.PML(extrude_structures=False)) explicitly.
• TerminalComponentModeler.ports and ModalComponentModeler.ports now use a discriminated union on the type field, so validation errors for a port dict are attributed to the correct port class instead of being scattered across every union branch.
• Fixed PolySlabSet to preserve its internal ring order across safe_update() and other vertex-space updates while still exporting area-sorted structures.
• Fixed mode solver picking the wrong sqrt root for lossless evanescent modes; direction is now resolved from time-averaged power flow with a passivity fallback.
• Fixed device characteristic DataArrays to expose value units and voltage coordinate units when simulation data is loaded.
• Fixed EMESimulation.plot_3d() to clip infinite structures to the simulation bounds.
• EME interface matching now uses the full solved modal basis as test rows, except modes with numerically unusable self-overlap, so high mode counts no longer slowly degrade S-matrix accuracy. Only the propagation trial basis is capped by EMEModeSweep.num_modes or EMEModeSpec.sort_spec.keep_modes; modes flagged increasing (Im(n_eff) < -EMEModeSpec.increasing_mode_tolerance) remain available as test rows. The default increasing-mode tolerance now ignores roundoff-level negative imaginary effective indices in lossless cases. The per-cell EMEModeSpec.num_modes cap is raised from 100 to 1000 for convergence studies; practical mode counts remain limited by interface memory and dense interface/stacking runtime.
• Fixed edge singularity correction for geometry groups and difference boolean operations in conformal meshing.
• Fixed RF/modeler diverged runs to report a clear task status error instead of trying to download missing aggregate data.

Removed

• Removed deprecated Scene.plot_heat_conductivity(), Scene.plot_structures_heat_conductivity(), and Scene.heat_conductivity_bounds(); use plot_heat_charge_property(property="heat_conductivity"), plot_structures_heat_charge_property(property="heat_conductivity"), and heat_charge_property_bounds(property="heat_conductivity").
• Removed deprecated AbstractSimulation.plot_structures_heat_conductivity() and HeatChargeSimulation.plot_heat_conductivity(); use scene.plot_structures_heat_charge_property(property="heat_conductivity") and plot_property(property="heat_conductivity").
• Removed the deprecated legacy config API and legacy config migration paths.
• Removed TopologyDesignRegion.params_uniform(), params_random, params_zeros, params_half, params_ones, AbstractOptimizer.initialize_result(params0), and AbstractOptimizer.run(..., params0=...). For direct parameter arrays, replace the TopologyDesignRegion.params_* helpers with NumPy arrays using region.params_shape, such as np.full(region.params_shape, value), np.random.random(region.params_shape), np.zeros(region.params_shape), 0.5 * np.ones(region.params_shape), or np.ones(region.params_shape). For optimizer starting parameters previously passed as params0, configure the design region before constructing or updating the enclosing design and optimizer; use CustomInitializationSpec(params=params0) to preserve an existing array, or RandomInitializationSpec(seed=...) for reproducible random starts.
• Removed deprecated SimulationData.plot_field(field_name="int"), SimulationData.plot_field(..., freq=...), and SimulationData.plot_field(..., time=...); use field_name="E", val="abs^2", plot_field(..., f=...), and plot_field(..., t=...).
• Removed deprecated to_field_monitors() method on terminal-based scattering-matrix ports (e.g. LumpedPort, WavePort); use to_monitors() instead.

Planned Deprecation

• Palik_Lossless is deprecated as a material-library variant name; material-library lookup now warns and returns Palik_LowLoss, while Palik_NoLoss provides zero-loss Palik fits where supported by low-loss source ranges.

Full Changelog: v2.11.2...v2.12.0.dev0