Settings reference

All simulation settings, grouped by category. Settings are saved in the project's FDTD settings block.

Reading and changing settings

The same values reach the solver from four surfaces:

The Simulate tab panels edit the run settings in the GUI. Advanced-mode settings appear when Advanced mode is on. Viewer settings such as Photorealistic, Show meshing, and Max FPS are set in the viewer that uses them and do not change the run.
rayrf project dump-settings --project FILE prints every setting with its value, default, units, and description, grouped by category. --changed-only shows only settings that differ from their default, --category NAME limits to one category, --advanced or --no-advanced limits to advanced-only or non-advanced settings, and --json emits a machine-readable list.
rayrf run --setting name=value overrides a setting for one run (repeatable). It is value-gated by the same gate as the GUI. A hard bound out of range refuses with exit 2, a soft bound out of range prints one warning and runs the value exactly as set. An unknown setting refuses with exit 2, and a renamed one names its replacement.
rayrf schema --what settings prints the machine contract: every field with its type, default, units, enum, and category.

Reading the table

Type and Default are the live values from the registry. A ui-only setting persists viewer or editor state and does not change the physics. An advanced setting surfaces in Advanced mode. A Caution note is the registry's warning about a common mistake for that setting.

All settings

Frequency band

Setting	Type	Default	Units	Notes	Description
`freq_min_hz`	number	`0`	Hz		Lower edge of the excitation band, in Hz. Also sets the reference wavelength for PML and air sizing. Caution: This field is in Hz. The CLI run flags and the GUI use MHz/GHz, so a value of 3e9 is 3 GHz.
`freq_max_hz`	number	`0`	Hz		Upper edge of the excitation band, in Hz. Sets the required mesh resolution (cells per wavelength at f_max). Caution: Must be greater than freq_min_hz.
`cw_enabled`	boolean	`false`	bool		Inject a continuous sinusoid at cw_freq_hz instead of a Gaussian pulse. Advanced-mode only: export refuses an auto-mode project with CW enabled. Caution: Continuous wave never rings down, so the run stops only at whichever step cap is live: auto_max_steps in Auto mode, adv_max_steps in Advanced mode when adv_max_steps_enabled is true, otherwise at the step counter's limit. Under a single tone the S-parameters are of limited meaning, the radiation pattern at the tone is meaningful, and both outputs stay available.
`cw_freq_hz`	number	`2.4e+09`	Hz		Continuous-wave excitation frequency, in Hz, used when cw_enabled is on.
`auto_freq_mode_centre`	boolean	`false`	bool	ui-only	UI input style for the auto-mode frequency band: f_min / f_max (False, the default) or centre plus bandwidth (True).

Mesh / cell size

Setting	Type	Default	Units	Description
`dx_mm`	number	`0.2`	mm	FDTD cell size in X. Smaller cells raise accuracy, memory, and runtime. Caution: In advanced mode this is used exactly. In auto mode it is derived from quality and overwritten.
`dy_mm`	number	`0.2`	mm	FDTD cell size in Y.
`dz_mm`	number	`0.2`	mm	FDTD cell size in Z. Must resolve the substrate thickness (aim for several cells per dielectric layer). Caution: In advanced mode dz is not snapped. If it does not divide the stackup height the substrate can land between grid lines.

Non-uniform mesh grading

Setting	Type	Default	Units	Notes	Description
`mesh_strategy`	string	`ratio`	enum	enum: ratio / custom	Select the sole mesh-grading owner: board-region Ratio grading or the Custom profile edited in Mesh View.
`mesh_grading_x_mult`	number	`1`	factor		Board-region refinement factor in X (1.0 means no refinement).
`mesh_grading_y_mult`	number	`1`	factor		Board-region refinement factor in Y.
`mesh_grading_z_mult`	number	`1`	factor		Board-region refinement factor in Z. Caution: A value of 2.0 halves the Z cell near the board, roughly doubling Z cells there and raising memory.
`mesh_grading_margin_mm`	number	`1`	mm		How far the fine-cell region extends beyond the board in every direction.
`mesh_grading_x_max_ratio`	number	`1.3`	ratio		Maximum cell-to-cell size ratio in the X grading transition. At or below 1 no transition can satisfy the ratio and the size jump would violate it.
`mesh_grading_y_max_ratio`	number	`1.3`	ratio		Maximum cell-to-cell size ratio in the Y grading transition. At or below 1 no transition can satisfy the ratio and the size jump would violate it.
`mesh_grading_z_max_ratio`	number	`1.3`	ratio		Maximum cell-to-cell size ratio in the Z grading transition. At or below 1 no transition can satisfy the ratio and the size jump would violate it.

Boundary conditions and PML

Setting	Type	Default	Units	Notes	Description
`bc_all`	string	`PML`		enum: PML / PEC / PMC / Custom	Boundary preset applied to all six faces, or Custom to set each face individually. Caution: PEC and PMC are hard walls with no absorber. Give every PEC/PMC face an explicit per-face spacing, otherwise it inherits the air margin sized for PML and the geometry can sit on the wall.
`pml_thickness_mm`	number	`4`	mm		Physical thickness of the PML absorber, the authoritative depth when pml_mode is manual. In the cells and auto modes the export derives the depth (pml_cells_manual x finest cell, or auto_pml_factor x wavelength) on every path and this field is display state. The PML is added outside the air margin (it extends the domain), so it never overlaps the geometry. Thickness only increases total cell count.
`pml_cells`	integer	`0`	cells		Resolved PML cell count. 0 means derive it from pml_thickness_mm at export. A positive value is a per-face floor, and the axis count is raised to ceil(pml_thickness_mm / cell) when the thickness needs more. In advanced mode with a manual thickness the thickness alone is authoritative and this count is not read.
`auto_pml_factor`	number	`0.1`	fraction		PML thickness as a fraction of the wavelength at f_min when auto PML is on (0.10 means lambda/10). The depth is realized as written. A thin absorber is warned about, never enlarged.
`pml_mode`	string	`cells`		enum: cells / auto / manual	How PML depth is specified: a cell count (pml_cells_manual), auto-sized from the wavelength at f_min, or the explicit pml_thickness_mm.
`pml_cells_manual`	integer	`8`	cells		PML absorber depth in cells per face when pml_mode is cells. The export pins every face to exactly this count on every path. A face declared PML needs at least one absorber cell to be one.
`bc_x_lo`	string	`PML`		enum: PML / PEC / PMC	Boundary type on the -X face when bc_all is Custom.
`bc_x_hi`	string	`PML`		enum: PML / PEC / PMC	Boundary type on the +X face when bc_all is Custom.
`bc_y_lo`	string	`PML`		enum: PML / PEC / PMC	Boundary type on the -Y face when bc_all is Custom.
`bc_y_hi`	string	`PML`		enum: PML / PEC / PMC	Boundary type on the +Y face when bc_all is Custom.
`bc_z_lo`	string	`PML`		enum: PML / PEC / PMC	Boundary type on the -Z (bottom) face when bc_all is Custom.
`bc_z_hi`	string	`PML`		enum: PML / PEC / PMC	Boundary type on the +Z (top) face when bc_all is Custom.
`bc_x_lo_spacing_enabled`	boolean	`false`	bool		Use a fixed -X gap (bc_x_lo_spacing_mm) instead of the auto/global air margin.
`bc_x_hi_spacing_enabled`	boolean	`false`	bool		Use a fixed +X gap (bc_x_hi_spacing_mm) instead of the auto/global air margin.
`bc_y_lo_spacing_enabled`	boolean	`false`	bool		Use a fixed -Y gap (bc_y_lo_spacing_mm) instead of the auto/global air margin.
`bc_y_hi_spacing_enabled`	boolean	`false`	bool		Use a fixed +Y gap (bc_y_hi_spacing_mm) instead of the auto/global air margin.
`bc_z_lo_spacing_enabled`	boolean	`false`	bool		Use a fixed -Z gap (bc_z_lo_spacing_mm) instead of the auto/global air margin.
`bc_z_hi_spacing_enabled`	boolean	`false`	bool		Use a fixed +Z gap (bc_z_hi_spacing_mm) instead of the auto/global air margin.
`bc_x_lo_spacing_mm`	number	`0`	mm		Fixed gap from the geometry to the -X boundary when its spacing override is enabled.
`bc_x_hi_spacing_mm`	number	`0`	mm		Fixed gap from the geometry to the +X boundary when its spacing override is enabled.
`bc_y_lo_spacing_mm`	number	`0`	mm		Fixed gap from the geometry to the -Y boundary when its spacing override is enabled.
`bc_y_hi_spacing_mm`	number	`0`	mm		Fixed gap from the geometry to the +Y boundary when its spacing override is enabled.
`bc_z_lo_spacing_mm`	number	`0`	mm		Fixed gap from the geometry to the -Z boundary when its spacing override is enabled. A Custom PEC/PMC face requires it (0 puts the wall flush, e.g. an infinite ground plane). PML faces fall back to the derived margin.
`bc_z_hi_spacing_mm`	number	`0`	mm		Fixed gap from the geometry to the +Z boundary when its spacing override is enabled. A Custom PEC/PMC face requires it. PML faces fall back to the derived margin.

Air margins / domain

Setting	Type	Default	Units	Notes	Description
`air_around_mm`	number	`10`	mm		Air gap in the XY plane from the meshed board edge to the side boundaries. A per-face spacing overrides it on that face.
`air_above_mm`	number	`10`	mm		Air gap above the topmost stackup plane to the upper boundary. A per-face top spacing overrides it.
`air_below_mm`	number	`10`	mm		Air gap below the bottom stackup plane to the lower boundary. A per-face bottom spacing overrides it.
`air_mode`	string	`cells`		enum: cells / mm / auto	How the advanced air margin is specified: a per-face cell count, the explicit air__mm values, or auto-sized from the wavelength at f_min. Caution: Every mode is resolved at export on every path: cells from air_cells x the face's own cell size, auto from auto_air__factor x the wavelength at f_min. In those two modes the air_*_mm fields are display state. Only air_mode=mm reads them.
`air_cells`	integer	`6`	cells		Air cells on every face when air_mode is cells. The export resolves the count against the face's own cell size (the coarser in-plane cell laterally, dz above and below).
`auto_air_enabled`	boolean	`false`	bool		Size the air margins automatically from the wavelength at f_min instead of using the fixed air_*_mm values.
`auto_air_sides_factor`	number	`0.25`	fraction		Side air margin as a fraction of the wavelength at f_min when auto air is on.
`auto_air_above_factor`	number	`0.25`	fraction		Above air margin as a fraction of the wavelength at f_min when auto air is on.
`auto_air_below_factor`	number	`0.25`	fraction		Below air margin as a fraction of the wavelength at f_min when auto air is on.

Run length and telemetry

Setting	Type	Default	Units	Notes	Description
`typical_speed_gcells_per_s`	number	`10`	GCell/s	ui-only	Saved throughput estimate used only for the UI runtime prediction.
`auto_max_steps`	integer	`1000000`	steps		Auto-mode safety cap on backend timesteps. In Advanced mode, adv_max_steps applies only when adv_max_steps_enabled is true. The max-steps CLI option forces a one-run cap in either mode. Caution: If the cap is hit before ringdown, the S-parameter and radiation results are not physically converged.
`ringdown_end_crit`	number	`1e-05`	ratio		Energy ratio (relative to peak) at which the run stops. Smaller means a longer, more converged run. Auto mode derives it from quality. Advanced mode honors the value as written. The floor is -120 dB: the control is logarithmic and zero has no dB representation.
`ringdown_check_steps`	integer	`250`	steps		How often, in steps, the ringdown energy criterion is evaluated. Also the step-telemetry window and the engines' temporal-blocking round length, so it is consumed on every run including CW.
`ringdown_min_steps`	integer	`0`	steps		Optional user floor before the ringdown criterion may stop the run, above the built-in floor of two excitation lengths that every run keeps. 0 (the default) adds nothing above that floor.
`sparam_delta_crit_db`	number	`-40`	dB		Threshold on the change in S-parameters between ringdown checks. It must be negative when sparam_early_stop is on. The threshold itself never enables or disables the stop.
`sparam_delta_check_steps`	integer	`0`	steps	advanced	How often, in steps, the S-parameter early-stop delta is evaluated. 0 reuses ringdown_check_steps.
`sparam_delta_consecutive`	integer	`2`	count	advanced	Consecutive stable S-parameter checks required before the early stop fires.
`sparam_min_steps`	integer	`10000`	steps		Minimum steps before the S-parameter early stop is allowed to fire (a floor so it cannot stop during source excitation).
`sparam_early_stop`	boolean	`false`	bool	advanced	Enable the early stop once the S-parameters stop changing by sparam_delta_crit_db across consecutive checks. This boolean is the sole enable for the criterion.
`telemetry_interval`	integer	`25`	steps	ui-only	Emit step telemetry every N steps. Lower values update the live charts more often at some compute cost.
`adv_max_steps`	integer	`1000000`	steps	advanced	Hard step cap applied when 'Max steps' is enabled. Honored on the GUI and CLI run paths. Caution: If the cap is hit before ringdown, the S-parameter and radiation results are not physically converged.
`adv_max_steps_enabled`	boolean	`false`		advanced	When set, the run stops at adv_max_steps. Honored on the GUI and CLI run paths.

Mesh convergence study

Setting	Type	Default	Units	Notes	Description
`auto_mesh_enabled`	boolean	`false`	bool	advanced	Advanced-mode toggle for the mesh convergence study.
`auto_convergence_enabled`	boolean	`false`	bool		Run a multi-pass mesh convergence study, refining until the tracked resonances stabilise.
`conv_source`	string	`S11`		enum: S11 / S21, advanced	Which S-parameter the convergence study tracks.
`conv_num_resonances`	integer	`1`	count	advanced	Number of deepest resonance dips matched between convergence passes.
`conv_freq_threshold_db`	number	`-20`	dB	advanced	Allowed per-resonance frequency shift between passes, as 10*log10(df/f) (-20 dB is about 1 percent).
`conv_depth_threshold_db`	number	`-20`	dB	advanced	Allowed per-resonance depth change between passes, in dB of the linear-magnitude difference.
`conv_mesh_refine_factor`	number	`1.26`	factor	advanced	Mesh division factor applied each convergence pass. Caution: 1.26 is about cbrt(2), roughly doubling cell count per pass. Larger values explode the cell count. Below 1 the step would coarsen instead of refine.
`conv_max_passes`	integer	`8`	count	advanced	Maximum number of convergence passes before stopping.

Radiation (NF2FF)

Setting	Type	Default	Units	Description
`enable_nf2ff`	boolean	`true`	bool	Compute the 3D radiation pattern, gain, and directivity via a near-field to far-field transform.
`skip_geometry_export`	boolean	`false`	bool	Skip writing geometry.vtk / geometry.vdb when a radiation or 3D-field run would normally request it. A suppression: with no geometry output requested it changes nothing and is still honored.
`nf2ff_num_freqs`	integer	`51`	count	Number of frequency points for the radiation-pattern output. The solver's NF2FF buffers hold 512 points, a fixed backend contract.

Surface currents

Setting	Type	Default	Units	Notes	Description
`enable_surface_currents`	boolean	`false`	bool		Record surface current density on a conductor layer (time-domain frames plus a frequency-domain DFT).
`surface_current_layer`	string				Conductor layer name to capture surface currents on.
`surface_current_interval_auto`	boolean	`true`	bool		Pick the time-domain capture stride automatically for 10 samples per period at f_max. Caution: When on, this overrides the manual surface_current_interval.
`surface_current_interval`	integer	`50`	steps		Save a time-domain surface-current frame every N steps when the auto stride is off.
`surface_current_num_freqs`	integer	`63`	count		Number of frequency points for the surface-current DFT. The solver's DFT buffers hold 512 points, a fixed backend contract.
`surface_current_view_domain`	string	`frequency`		enum: frequency / time, ui-only	Saved viewer preference for surface currents: frequency-domain or time-domain.

3D field export

Setting	Type	Default	Units	Notes	Description
`save_vtk`	boolean	`false`	bool		Write full 3D field frames during the run. Caution: Produces very large files and is disk-bound. Enable only when you need full-volume fields.
`export_e_mag`	boolean	`true`	bool		Write the E-field magnitude \|E\| (V/m) for each exported frame. The default field-export content. Caution: Turn it off only to export H or energy alone. With all three field types off there is nothing to write.
`export_h_mag`	boolean	`false`	bool		Also write the H-field magnitude \|H\| (A/m) for each exported frame. H is time-centered to the E level before the magnitude.
`export_energy`	boolean	`false`	bool		Also write the total field energy density U (J/m^3) for each exported frame, combining the aligned E and H at each cell.
`export_ex`	boolean	`false`	bool		Also write the signed Ex component (V/m) for each exported frame.
`export_ey`	boolean	`false`	bool		Also write the signed Ey component (V/m) for each exported frame.
`export_ez`	boolean	`false`	bool		Also write the signed Ez component (V/m) for each exported frame.
`export_hx`	boolean	`false`	bool		Also write the signed Hx component (A/m) for each exported frame, time-centered to the E level.
`export_hy`	boolean	`false`	bool		Also write the signed Hy component (A/m) for each exported frame, time-centered to the E level.
`export_hz`	boolean	`false`	bool		Also write the signed Hz component (A/m) for each exported frame, time-centered to the E level.
`vtk_dump_interval`	integer	`50`	steps		Write a field frame every N steps when field export is on and the auto stride is off.
`vtk_dump_interval_auto`	boolean	`false`	bool		Floor the field-export stride to the Nyquist-safe value derived from f_max. Caution: When on, this overrides the manual vtk_dump_interval.
`field_export_range_enabled`	boolean	`false`	bool		Limit field frames to a step window. The solver still runs every step but skips writes outside it. Caution: Off by default, so frames are written at the export stride for the entire run when save_vtk is on.
`field_export_range_start`	integer	`0`	steps		First step (inclusive) written when the field-export range is enabled.
`field_export_range_end`	integer	`10000`	steps		Last step (inclusive) written when the field-export range is enabled.
`field_format`	string	`rff`		enum: rff / vtk / vdb	3D field storage format: RFF compresses signed logarithmic samples without threshold pruning, VTK stores fp32 samples, and VDB stores sparse volumes.
`vdb_threshold_frac`	number	`0.001`	fraction		VDB sparsification cutoff as a fraction of each selected array's peak magnitude. Voxels below it collapse to the pruned background (0 disables). Caution: Very small values keep more of the wave tail and enlarge files.

Backend selection

Setting	Type	Default	Units	Notes	Description
`use_cpu_backend`	boolean	`none`	bool		Run on the CPU (OpenMP) backend. None defers to the saved app preference. The GUI auto-enables this when no CUDA GPU is found.

Mode and quality

Setting	Type	Default	Units	Notes	Description
`sim_mode`	string	`auto`		enum: auto / advanced	Simulation mode: auto derives the mesh from quality, advanced uses the explicit mesh and boundary fields.
`auto_quality`	number	`1`	level		Continuous auto-mode quality from 0.0 to 3.0, interpolating cells per wavelength, PML, and convergence criteria.
`auto_min_feature_x_mm`	number	`0`	mm		Smallest feature the mesh resolves in X. Set it and the mesh refines X to resolve it. Measured copper below it is reported as a warning, not silently meshed. 0 means no feature-size constraint on X, so measured copper only warns and the cell stays at the cells-per-wavelength and dielectric baseline. Caution: Per-axis and independent. Setting one axis does not tighten the others, which can leave an anisotropic mesh.
`auto_min_feature_y_mm`	number	`0`	mm		Smallest feature the mesh resolves in Y. Set it and the mesh refines Y to resolve it. Measured copper below it is reported as a warning, not silently meshed. 0 means no feature-size constraint on Y, so measured copper only warns and the cell stays at the cells-per-wavelength and dielectric baseline.
`auto_min_feature_z_mm`	number	`0`	mm		Smallest feature the mesh resolves in Z. A pure resolution floor: the mesh refines Z to resolve it. 0 means no feature-size constraint on Z, so the cell stays at the dielectric and cells-per-wavelength baseline. Stackup layers are always resolved and never excluded.

Editor preferences

Setting	Type	Default	Units	Notes	Description
`editor_grid_mm`	number	`1`	mm	ui-only	Editor snap-grid spacing.
`snap_enabled`	boolean	`true`	bool	ui-only	Whether the editor snaps to the grid.

Result-viewer UI state

Setting	Type	Default	Units	Notes	Description
`fv_viewer_mode`	string	`currents`		enum: fields / currents, ui-only	Field viewer active mode.
`fv_cmap`	string	`coolwarm`		ui-only	Field viewer colormap name.
`fv_log_scale`	boolean	`false`	bool	ui-only	Field viewer linear vs log scale (fields only).
`fv_field_scale_mode_idx`	integer	`1`		ui-only	Field viewer scale mode index (0 frame-based, 1 local, 2 global).
`fv_field_ref_frame`	integer	`0`		ui-only	Field viewer reference frame index for scaling.
`fv_show_geometry`	boolean	`true`	bool	ui-only	Field viewer geometry overlay visibility.
`fv_geom_opacity`	integer	`100`	percent	ui-only	Field viewer geometry overlay opacity in percent.
`fv_photorealistic_geometry`	boolean	`true`	bool	ui-only	E/H field viewer geometry uses studio lighting, matte cream dielectric, rough copper, local field illumination, and contact shading around copper edges.
`fv_show_meshing`	boolean	`false`	bool	ui-only	Field viewer geometry shows mesh cell outlines, independently of material lighting.
`fv_max_fps`	number	`30`	FPS	ui-only	Maximum playback rate for E/H fields and time-domain surface currents, with slower playback when loading or rendering takes longer.
`fv_field_frame_idx`	integer	`0`		ui-only	Field viewer current frame index.
`fv_sc_freq_idx`	integer	`-1`		ui-only	Surface-current viewer frequency index (-1 defaults to centre).
`fv_sc_time_idx`	integer	`0`		ui-only	Surface-current viewer time-frame index.
`fv_sc_scale_mode_idx`	integer	`2`		ui-only	Surface-current viewer scale mode index (0 ref-based, 1 local, 2 global).
`fv_sc_ref_idx`	integer	`0`		ui-only	Surface-current viewer reference index for scaling.
`fv_sc_cmap`	string	`inferno`		ui-only	Surface-current viewer colormap name.
`fv_rad_freq_idx`	integer	`-1`		ui-only	Radiation tab frequency index (-1 defaults to centre).
`fv_rad_viewer_mode`	string	`polar`		enum: polar / 3d, ui-only	Radiation viewer mode.
`fv_rad_show_geometry`	boolean	`true`	bool	ui-only	Radiation viewer geometry overlay visibility.
`fv_rad_show_pattern`	boolean	`true`	bool	ui-only	Radiation viewer 3D pattern visibility.
`fv_rad_geom_opacity`	integer	`100`	percent	ui-only	Radiation viewer geometry opacity in percent.
`fv_rad_show_meshing`	boolean	`true`	bool	ui-only	Radiation viewer geometry shows mesh cell outlines.
`fv_rad_photorealistic`	boolean	`false`	bool	ui-only	Radiation viewer geometry uses matte cream dielectric and rough copper with physical lighting.
`fv_rad_pattern_opacity`	integer	`85`	percent	ui-only	Radiation viewer pattern-surface opacity in percent.
`fv_rad_polar_floor_dbi`	number	`-25`	dBi	ui-only	Radiation viewer polar plot floor in dBi. A sample below it is drawn at the chart center, and the floor ring is labeled with this value.
`fv_rad_auto_position`	boolean	`true`	bool	ui-only	Radiation viewer auto-computes the pattern origin.
`fv_rad_auto_scale`	boolean	`true`	bool	ui-only	Radiation viewer auto-computes the pattern scale.
`fv_rad_pos_x_mm`	number	`0`	mm	ui-only	Radiation viewer manual pattern origin X.
`fv_rad_pos_y_mm`	number	`0`	mm	ui-only	Radiation viewer manual pattern origin Y.
`fv_rad_pos_z_mm`	number	`0`	mm	ui-only	Radiation viewer manual pattern origin Z.
`fv_rad_pattern_scale`	number	`1`	factor	ui-only	Radiation viewer manual pattern scale factor.
`fv_rad_split_view`	boolean	`true`	bool	ui-only	Radiation viewer shows polar and 3D side by side.
`fv_rad_split_sizes`	array	`[]`		ui-only	Radiation viewer splitter pixel widths.
`fv_rad_camera_position`	array	`[]`		ui-only	Saved radiation viewer 3D camera (9 floats: position, focal point, up vector).
`fv_mesh_show_meshing`	boolean	`true`	bool	ui-only	Simulate mesh preview shows mesh cell outlines.
`fv_mesh_photorealistic`	boolean	`false`	bool	ui-only	Simulate mesh preview uses matte cream dielectric and rough copper with physical lighting.
`fv_sparams_visible_panels`	array	`['magnitude', 'smith']`		ui-only	S-parameter tab visible panels, in canonical order (magnitude, smith, impedance, network). Never empty. The matching-network panel is selectable only when the run recorded network loss.
`fv_sparams_split_sizes`	array	`[]`		ui-only	S-parameter tab splitter pixel widths, one per visible panel.

Advanced-mode shadow values

Setting	Type	Default	Units	Notes	Description
`adv_dx_mm`	number	`0.2`	mm	advanced, ui-only	Advanced-mode shadow value. Mirrors 'dx_mm': FDTD cell size in X. Smaller cells raise accuracy, memory, and runtime.
`adv_dy_mm`	number	`0.2`	mm	advanced, ui-only	Advanced-mode shadow value. Mirrors 'dy_mm': FDTD cell size in Y.
`adv_dz_mm`	number	`0.2`	mm	advanced, ui-only	Advanced-mode shadow value. Mirrors 'dz_mm': FDTD cell size in Z. Must resolve the substrate thickness (aim for several cells per dielectric layer).
`adv_air_around_mm`	number	`10`	mm	advanced, ui-only	Advanced-mode shadow value. Mirrors 'air_around_mm': Air gap in the XY plane from the meshed board edge to the side boundaries. A per-face spacing overrides it on that face.
`adv_air_above_mm`	number	`10`	mm	advanced, ui-only	Advanced-mode shadow value. Mirrors 'air_above_mm': Air gap above the topmost stackup plane to the upper boundary. A per-face top spacing overrides it.
`adv_air_below_mm`	number	`10`	mm	advanced, ui-only	Advanced-mode shadow value. Mirrors 'air_below_mm': Air gap below the bottom stackup plane to the lower boundary. A per-face bottom spacing overrides it.
`adv_auto_air_enabled`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'auto_air_enabled': Size the air margins automatically from the wavelength at f_min instead of using the fixed air_*_mm values.
`adv_auto_air_sides_factor`	number	`0.25`	fraction	advanced, ui-only	Advanced-mode shadow value. Mirrors 'auto_air_sides_factor': Side air margin as a fraction of the wavelength at f_min when auto air is on.
`adv_auto_air_above_factor`	number	`0.25`	fraction	advanced, ui-only	Advanced-mode shadow value. Mirrors 'auto_air_above_factor': Above air margin as a fraction of the wavelength at f_min when auto air is on.
`adv_auto_air_below_factor`	number	`0.25`	fraction	advanced, ui-only	Advanced-mode shadow value. Mirrors 'auto_air_below_factor': Below air margin as a fraction of the wavelength at f_min when auto air is on.
`adv_air_mode`	string	`cells`		advanced, ui-only	Advanced-mode shadow value. Mirrors 'air_mode': How the advanced air margin is specified: a per-face cell count, the explicit air_*_mm values, or auto-sized from the wavelength at f_min.
`adv_air_cells`	integer	`6`	cells	advanced, ui-only	Advanced-mode shadow value. Mirrors 'air_cells': Air cells on every face when air_mode is cells. The export resolves the count against the face's own cell size (the coarser in-plane cell laterally, dz above and below).
`adv_pml_thickness_mm`	number	`4`	mm	advanced, ui-only	Advanced-mode shadow value. Mirrors 'pml_thickness_mm': Physical thickness of the PML absorber, the authoritative depth when pml_mode is manual. In the cells and auto modes the export derives the depth (pml_cells_manual x finest cell, or auto_pml_factor x wavelength) on every path and this field is display state. The PML is added outside the air margin (it extends the domain), so it never overlaps the geometry. Thickness only increases total cell count.
`adv_auto_pml_factor`	number	`0.1`	fraction	advanced, ui-only	Advanced-mode shadow value. Mirrors 'auto_pml_factor': PML thickness as a fraction of the wavelength at f_min when auto PML is on (0.10 means lambda/10). The depth is realized as written. A thin absorber is warned about, never enlarged.
`adv_pml_mode`	string	`cells`		advanced, ui-only	Advanced-mode shadow value. Mirrors 'pml_mode': How PML depth is specified: a cell count (pml_cells_manual), auto-sized from the wavelength at f_min, or the explicit pml_thickness_mm.
`adv_pml_cells_manual`	integer	`8`	cells	advanced, ui-only	Advanced-mode shadow value. Mirrors 'pml_cells_manual': PML absorber depth in cells per face when pml_mode is cells. The export pins every face to exactly this count on every path. A face declared PML needs at least one absorber cell to be one.
`adv_ringdown_end_crit`	number	`1e-05`	ratio	advanced, ui-only	Advanced-mode shadow value. Mirrors 'ringdown_end_crit': Energy ratio (relative to peak) at which the run stops. Smaller means a longer, more converged run. Auto mode derives it from quality. Advanced mode honors the value as written. The floor is -120 dB: the control is logarithmic and zero has no dB representation.
`adv_ringdown_min_steps`	integer	`0`	steps	advanced, ui-only	Advanced-mode shadow value. Mirrors 'ringdown_min_steps': Optional user floor before the ringdown criterion may stop the run, above the built-in floor of two excitation lengths that every run keeps. 0 (the default) adds nothing above that floor.
`adv_nf2ff_num_freqs`	integer	`51`	count	advanced, ui-only	Advanced-mode shadow value. Mirrors 'nf2ff_num_freqs': Number of frequency points for the radiation-pattern output. The solver's NF2FF buffers hold 512 points, a fixed backend contract.
`adv_save_vtk`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'save_vtk': Write full 3D field frames during the run.
`adv_vtk_dump_interval`	integer	`50`	steps	advanced, ui-only	Advanced-mode shadow value. Mirrors 'vtk_dump_interval': Write a field frame every N steps when field export is on and the auto stride is off.
`adv_vtk_dump_interval_auto`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'vtk_dump_interval_auto': Floor the field-export stride to the Nyquist-safe value derived from f_max.
`adv_field_format`	string	`rff`		advanced, ui-only	Advanced-mode shadow value. Mirrors 'field_format': 3D field storage format: RFF compresses signed logarithmic samples without threshold pruning, VTK stores fp32 samples, and VDB stores sparse volumes.
`adv_vdb_threshold_frac`	number	`0.001`	fraction	advanced, ui-only	Advanced-mode shadow value. Mirrors 'vdb_threshold_frac': VDB sparsification cutoff as a fraction of each selected array's peak magnitude. Voxels below it collapse to the pruned background (0 disables).
`adv_field_export_range_enabled`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'field_export_range_enabled': Limit field frames to a step window. The solver still runs every step but skips writes outside it.
`adv_field_export_range_start`	integer	`0`	steps	advanced, ui-only	Advanced-mode shadow value. Mirrors 'field_export_range_start': First step (inclusive) written when the field-export range is enabled.
`adv_field_export_range_end`	integer	`10000`	steps	advanced, ui-only	Advanced-mode shadow value. Mirrors 'field_export_range_end': Last step (inclusive) written when the field-export range is enabled.
`adv_auto_mesh_enabled`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'auto_mesh_enabled': Advanced-mode toggle for the mesh convergence study.
`adv_conv_source`	string	`S11`		advanced, ui-only	Advanced-mode shadow value. Mirrors 'conv_source': Which S-parameter the convergence study tracks.
`adv_conv_num_resonances`	integer	`1`	count	advanced, ui-only	Advanced-mode shadow value. Mirrors 'conv_num_resonances': Number of deepest resonance dips matched between convergence passes.
`adv_conv_freq_threshold_db`	number	`-20`	dB	advanced, ui-only	Advanced-mode shadow value. Mirrors 'conv_freq_threshold_db': Allowed per-resonance frequency shift between passes, as 10*log10(df/f) (-20 dB is about 1 percent).
`adv_conv_depth_threshold_db`	number	`-20`	dB	advanced, ui-only	Advanced-mode shadow value. Mirrors 'conv_depth_threshold_db': Allowed per-resonance depth change between passes, in dB of the linear-magnitude difference.
`adv_conv_mesh_refine_factor`	number	`1.26`	factor	advanced, ui-only	Advanced-mode shadow value. Mirrors 'conv_mesh_refine_factor': Mesh division factor applied each convergence pass.
`adv_conv_max_passes`	integer	`8`	count	advanced, ui-only	Advanced-mode shadow value. Mirrors 'conv_max_passes': Maximum number of convergence passes before stopping.
`adv_enable_surface_currents`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'enable_surface_currents': Record surface current density on a conductor layer (time-domain frames plus a frequency-domain DFT).
`adv_surface_current_layer`	string			advanced, ui-only	Advanced-mode shadow value. Mirrors 'surface_current_layer': Conductor layer name to capture surface currents on.
`adv_surface_current_interval_auto`	boolean	`true`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'surface_current_interval_auto': Pick the time-domain capture stride automatically for 10 samples per period at f_max.
`adv_surface_current_interval`	integer	`50`	steps	advanced, ui-only	Advanced-mode shadow value. Mirrors 'surface_current_interval': Save a time-domain surface-current frame every N steps when the auto stride is off.
`adv_surface_current_num_freqs`	integer	`63`	count	advanced, ui-only	Advanced-mode shadow value. Mirrors 'surface_current_num_freqs': Number of frequency points for the surface-current DFT. The solver's DFT buffers hold 512 points, a fixed backend contract.
`adv_mesh_grading_x_mult`	number	`1`	factor	advanced, ui-only	Advanced-mode shadow value. Mirrors 'mesh_grading_x_mult': Board-region refinement factor in X (1.0 means no refinement).
`adv_mesh_grading_y_mult`	number	`1`	factor	advanced, ui-only	Advanced-mode shadow value. Mirrors 'mesh_grading_y_mult': Board-region refinement factor in Y.
`adv_mesh_grading_z_mult`	number	`1`	factor	advanced, ui-only	Advanced-mode shadow value. Mirrors 'mesh_grading_z_mult': Board-region refinement factor in Z.
`adv_mesh_grading_margin_mm`	number	`1`	mm	advanced, ui-only	Advanced-mode shadow value. Mirrors 'mesh_grading_margin_mm': How far the fine-cell region extends beyond the board in every direction.
`adv_mesh_grading_x_max_ratio`	number	`1.3`	ratio	advanced, ui-only	Advanced-mode shadow value. Mirrors 'mesh_grading_x_max_ratio': Maximum cell-to-cell size ratio in the X grading transition. At or below 1 no transition can satisfy the ratio and the size jump would violate it.
`adv_mesh_grading_y_max_ratio`	number	`1.3`	ratio	advanced, ui-only	Advanced-mode shadow value. Mirrors 'mesh_grading_y_max_ratio': Maximum cell-to-cell size ratio in the Y grading transition. At or below 1 no transition can satisfy the ratio and the size jump would violate it.
`adv_mesh_grading_z_max_ratio`	number	`1.3`	ratio	advanced, ui-only	Advanced-mode shadow value. Mirrors 'mesh_grading_z_max_ratio': Maximum cell-to-cell size ratio in the Z grading transition. At or below 1 no transition can satisfy the ratio and the size jump would violate it.
`adv_cw_enabled`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'cw_enabled': Inject a continuous sinusoid at cw_freq_hz instead of a Gaussian pulse. Advanced-mode only: export refuses an auto-mode project with CW enabled.
`adv_cw_freq_hz`	number	`2.4e+09`	Hz	advanced, ui-only	Advanced-mode shadow value. Mirrors 'cw_freq_hz': Continuous-wave excitation frequency, in Hz, used when cw_enabled is on.
`adv_sparam_early_stop`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'sparam_early_stop': Enable the early stop once the S-parameters stop changing by sparam_delta_crit_db across consecutive checks. This boolean is the sole enable for the criterion.
`adv_sparam_delta_crit_db`	number	`-40`	dB	advanced, ui-only	Advanced-mode shadow value. Mirrors 'sparam_delta_crit_db': Threshold on the change in S-parameters between ringdown checks. It must be negative when sparam_early_stop is on. The threshold itself never enables or disables the stop.
`adv_sparam_min_steps`	integer	`10000`	steps	advanced, ui-only	Advanced-mode shadow value. Mirrors 'sparam_min_steps': Minimum steps before the S-parameter early stop is allowed to fire (a floor so it cannot stop during source excitation).
`adv_enable_nf2ff`	boolean	`true`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'enable_nf2ff': Compute the 3D radiation pattern, gain, and directivity via a near-field to far-field transform.
`adv_skip_geometry_export`	boolean	`false`	bool	advanced, ui-only	Advanced-mode shadow value. Mirrors 'skip_geometry_export': Skip writing geometry.vtk / geometry.vdb when a radiation or 3D-field run would normally request it. A suppression: with no geometry output requested it changes nothing and is still honored.