Concept index

The routing table. Search a concept (the search icon or S), open the named files, start reading at the entry symbol. Paths are repo-relative; every row was verified against the tree. For API detail run cargo doc --open -p <crate> locally - every crate exposes a prelude. For prose depth, follow the chapter linked at each group heading.

Boot and frame flow

Depth: Architecture.

Concept	Crate(s)	Key files	Entry symbol	Orientation
App boot, app assembly, plugin order	`nova_core`	`crates/nova_core/src/lib.rs`	`AppBuilder`	`build()` wires the whole plugin stack; game binary + CLI flags in `src/main.rs`.
Game states, pause	`nova_gameplay`, `nova_menu`	`crates/nova_gameplay/src/lib.rs`, `crates/nova_menu/src/pause.rs`	`GameStates`, `PauseStates`	State enums + `GameMode` live in gameplay; ESC overlay, `toggle_pause` and the clock freeze in menu.
Frame flow: Update vs FixedUpdate	`nova_ship`, `nova_gameplay`	`crates/nova_ship/src/lib.rs`, `crates/nova_gameplay/src/plugin.rs`	`SpaceshipSystems`	`NovaShipPlugin` chains the set brackets identically in both schedules; avian physics runs in `FixedPostUpdate`. Which schedule your system goes in: the Architecture chapter.
Units: meters, and the one engine seam	`nova_events`, `nova_ui`	`crates/nova_events/src/units.rs`, `crates/nova_events/src/scale.rs`, `crates/nova_ui/src/units.rs`	`Meters`, `METERS_PER_UNIT`	Everything authored, named as a constant or shown to a player is SI; Bevy, avian, meshes and the build grid count in world units at 10 m each. `to_engine`/`from_engine` are the only crossing and every call site is a documented boundary; `nova_ui::units` formats a readout without converting. The whole rule, and what stays engine-side: Architecture.
Asset loading gate, mod merge	`nova_assets`	`crates/nova_assets/src/plugin.rs`, `crates/nova_assets/src/merge.rs`	`GameAssetsPlugin`	`GameAssetsStates` gates entry to the menu/game; `register_bundles` merges base + enabled mods into the `Game*` resources.

The ship

Depth: Ship sections internals.

Concept	Crate(s)	Key files	Entry symbol	Orientation
Ship building from sections	`nova_scenario`, `nova_ship`	`crates/nova_scenario/src/objects/spaceship.rs`, `crates/nova_ship/src/sections/base_section.rs`	`insert_spaceship_sections`	Observer on the ship root spawns one child per `SectionKind` config, resolving prototypes; `SpaceshipConfig` is the authored shape.
Section integrity: damage, disable, destroy	`nova_gameplay`	`crates/nova_gameplay/src/integrity/mod.rs`, `crates/nova_gameplay/src/damage.rs`	`NovaIntegrityPlugin`	`Health` store and the disable/destroy chain; typed `DamageType` + the travel rule (`apply_damage`, `pierce_remainder`). Health decides WHEN a body dies; the two readings below decide what it looks like.
How far gone a body looks	`nova_gameplay`	`crates/nova_gameplay/src/integrity/erosion.rs`	`DamageLevel`	One scalar, 0..1, derived from the entity’s OWN `Health`. Grades every whole-body effect.
Where a body was hit (marks, carve cost, merge)	`nova_gameplay`	`crates/nova_gameplay/src/integrity/carve.rs`	`DamageMarks`, `mark_radius`	Spheres in the body’s local frame, priced by what the hit ABSORBED at `DAMAGE_PER_UNIT_VOLUME` (8 hp per cubic WORLD unit, so per 1000 m^3 - an inverse volume, and engine-side for that reason); `record_blast_marks` cuts one crater per body.
Authored per-section damage looks	`nova_ship`	`crates/nova_ship/src/sections/damage_effects.rs`, `damage_cracks.rs`, `damage_sparks.rs`, `damage_plume.rs`	`DamageEffects`, `fit_damage_effects`	`Cracks`/`Sparks`/`Plume`, one component each, default `[Cracks]`. No ship section ever loses geometry.
Carve debris: dust and severed pieces	`nova_gameplay`	`crates/nova_gameplay/src/integrity/spew.rs`, `crates/nova_gameplay/src/integrity/chunk.rs`	`CarveSpew`, `ShardLook`, `spawn_carved_chunk`	Shards are keyed on the WEAPON CLASS - kinetic and pierce chip, explosive does not; only a cut that SEVERED material spawns a real body, floored at `CHUNK_MIN_VOLUME`.
Severing, wreck fragments, structural collapse	`nova_ship`	`crates/nova_ship/src/sections/integrity.rs`	`ShipIntegrityPlugin`	Builds the section graph, splits disconnected structure (`sever_disconnected_structures` -> `ShipWreckFragmentMarker`), runs `cascade_structural_collapse`.
Neutralization (combat-dead)	`nova_gameplay`	`crates/nova_gameplay/src/integrity/neutralize.rs`	`NeutralizedMarker`	An armed ship that loses all weapons, or the flight computer it had, fires `OnNeutralizedEvent`; an unarmed ship instead goes this way on the last working thruster it ever had (`HadThruster`); the hull may survive.
Neutralized brake (a beaten hull stops on its own RCS)	`nova_ship`	`crates/nova_ship/src/flight/neutralized_brake.rs`	`NeutralizedBrakeType`, `neutralized_brake_system`	A neutralized non-player, non-station root brakes toward world rest by writing its `RcsIntent`, paid from its own `RcsBudget`; no engine needed. Docked, no computer, RCS off, empty, or a well past `RCS_GRAVITY_AUTHORITY` ends it for good; AI writers and helm orders refuse the hull.
Procedural hulls: the collapse, the plan	`nova_wfc`	`crates/nova_wfc/src/lib.rs`, `crates/nova_wfc/src/collapse.rs`, `crates/nova_wfc/src/tiles.rs`, `crates/nova_wfc/src/plan.rs`	`TileSet`, `WfcPlan`	`TileSet::build` reads a `WfcPlan` against the section catalog; `hull()` collapses one seed into a `ShipDesign` and runs it through the game’s own content lint before handing it out. The plan is CODE, not content: `WfcPlan::standard_hull` is the shipped one, and each caller (the editor’s Generate block, `wfc_arena`) builds its own from that plus its own UI rows. Grid geometry, seeds and zones: `crates/nova_wfc/src/grid.rs`. Whether a part can stand on the grid at all is `nova_ship::cell_grid_fit`, and `nova_ship::oriented_part` reads it as grid cells at one cube rotation (`crates/nova_ship/src/sections/cell_grid.rs`); the open-world part snapshot and ship layout (`crates/nova_world_base/src/ship_layout.rs`) read both too.
Ship skins, styles, greebles	`nova_ship`	`crates/nova_ship/src/sections/shell_skin.rs`, `crates/nova_ship/src/sections/skin_style.rs`, `crates/nova_ship/src/sections/skin_surface.rs`, `crates/nova_ship/src/sections/greeble_solver.rs`, `crates/nova_ship/src/sections/skin_decor.rs`	`ShipSkinPlugin`	Cladding derived from structure; styles resolve by id (`ShipStyleConfig`, `GameStyles`). A style authors a two-surface `StylePalette`, its fixtures and `greeble_rules` (`GreebleRules`: link types, greebles with four link points, `near` terms, caps). `solve_decor` solves the rules over the skin’s quad graph (`skin_surface`, `solve_greebles`) with the seed `greeble_seed(style id)`.
Turrets, aiming	`nova_ship`	`crates/nova_ship/src/sections/turret_section/mod.rs`, `crates/nova_ship/src/sections/turret_section/aim.rs`	`TurretSectionPlugin`	Authored joint tree; lead-intercept aim (`update_turret_aim_point`, `muzzle_on_target`); arcs and firing in sibling files.
Torpedoes, point defense	`nova_ship`	`crates/nova_ship/src/sections/torpedo_section/mod.rs`, `crates/nova_ship/src/input/point_defense/mod.rs`	`TorpedoSectionPlugin`, `SpaceshipPointDefensePlugin`	Bay + guided round lifecycle (`TorpedoGuidance`, `TorpedoBlast`); PD splits target assignment from mount authority (borrowed player mounts).
The spinal lance: commit, charge, shot, recoil	`nova_ship`	`crates/nova_ship/src/sections/railgun_section/mod.rs`, `crates/nova_ship/src/sections/railgun_section/firing.rs`	`RailgunSectionPlugin`, `RailgunCharge`	The hull aims it. `charge_and_fire_railgun` runs the whole cycle in one fixed-step system; the slug is a Pierce round with `layers: u32::MAX`, so `slug_power` alone bounds it. The AI’s crude commit envelope: `input/ai/railgun.rs` (`AIRailgun`).
The rake: a slug that widens its cut	`nova_gameplay`, `nova_ship`	`crates/nova_gameplay/src/rounds.rs`, `crates/nova_ship/src/sections/railgun_section/firing.rs`	`RoundRake`, `sweep_raking`	Authored `rake_radius` inserts `RoundRake`; three passes per step - the tip arms bodies it hits, a sphere trailing it sweeps each armed body’s colliders, contacts charge by depth then axis outward out of the one budget. Measured in `examples/systems/system_railgun_lance.rs`.
Docking: the candidate pair, the joint, the break	`nova_ship`	`crates/nova_ship/src/sections/docking_section/port.rs`, `crates/nova_ship/src/sections/docking_section/admission.rs`, `crates/nova_ship/src/sections/docking_section/connection.rs`	`DockingPorts`, `DockAdmission`, `DockingConnection`, `DockingSystems::Release`	`DOCK` names two hulls; a new dock needs both a port candidate (face gap between RETRACTED faces, opposed axes, relative speed, graded on the STRICTER of the two envelopes and tie-broken on `EntityId`) and `DockAdmission`, which a ship target refuses while Hostile, Enemy, answering fire, or fighting (a neutralized target always admits) and a station target refuses while every port is held, or is a living station on the Enemy side or hostile to the ship (`station_admission`; a derelict or neutralized station and a station the player owns, `OwnedStationMarker`, admit on any side, and a station’s refusal reaches the HUD as a notice through `FlightVerbHints::dock_refusal`). One `FixedJoint` with an explicit anchor and basis holds the pose they met in; nothing writes a velocity. A ship holds one connection; a station is a hub holding one per port (`StationDock`/`StationDocks`, `DockedStation`), and the station with every docked hull is one assembly. One hull drives the assembly: `DockingConnection.helm` (`DockedHelmType`: `Neutral`, `Held(player)`, or `Station(station)` for a living station, which refuses `HELM`; a derelict or neutralized hull, ship or station, hands the helm to the player at capture) picks it, `DockedShip.drives`/`DockedStation.drives` gates every actuator on the other roots, and `DockedAssembly` gives the driver the combined mass, centre of mass and inertia. `DOCK` again from either hull, or the player provoking a docked Neutral past `NEUTRAL_RETALIATION_THRESHOLD`, are the pilot-facing ways out.
The bore sight	`nova_hud`	`crates/nova_hud/src/bore_sight.rs`	`BoreSightPlugin`	The lance’s line of fire in world space, walked through the same `pierce_remainder` as the round; a ring per section the shot would destroy; gated on `WeaponsHot`, dimmed on an empty magazine.
Flight autopilot verbs (STOP, GOTO, ORBIT, MATCH, the AI DOCK approach), PD attitude controller	`nova_ship`	`crates/nova_ship/src/flight/state.rs`, `crates/nova_ship/src/flight/autopilot.rs`, `crates/nova_ship/src/flight/dock_corridor.rs`, `crates/nova_ship/src/sections/controller_section.rs`, `crates/nova_ship/src/physics/pd_controller.rs`	`ShipCapabilities`, `Autopilot`	The ship ROOT carries what it is permitted to do; the flight layer flies the maneuvers (`NovaFlightPlugin`); `PDControllerPlugin` is the attitude loop, and a controller section is the attitude hardware it needs. MATCH is `AutopilotAction::MatchTarget`, flown on RCS alone.
Leg detours around rocks and planetoids	`nova_ship`	`crates/nova_ship/src/flight/navigation.rs`	`plan_leg`, `DetourPolicy`	The sphere-detour planner every GOTO and GotoPos leg asks each tick, and the AI formation leg in its leader’s frame. It holds no policy: the caller states the clearance in a `DetourPolicy` and gets a corner back.
Radar locking, targeting	`nova_ship`	`crates/nova_ship/src/input/targeting/mod.rs`, `crates/nova_ship/src/input/targeting/state.rs`	`SpaceshipTargetingPlugin`	Radar search writes the two sticky lock slots on the ship root: `TravelLock`, `CombatLock`.
Gravity wells	`nova_gameplay`	`crates/nova_gameplay/src/gravity.rs`	`GravityWell`	Inverse-square wells with an SOI cutoff; only anchored planets and authored anchors publish one. Ships and asteroids feel their pull.

Scenario and modding

Depth: Scenario engine.

Concept	Crate(s)	Key files	Entry symbol	Orientation
Scenario engine, mission scripting	`nova_scenario`, `nova_events`	`crates/nova_scenario/src/lib.rs`, `crates/nova_events/src/engine.rs`	`NovaScenarioPlugin`	A scenario is handlers = event + filters + actions over `NovaEventWorld`; the generic queue/dispatch (`EventHandler`) is `nova_events`.
Scenario events, filters, actions (modding events)	`nova_scenario`	`crates/nova_scenario/src/events.rs`, `crates/nova_scenario/src/filters.rs`, `crates/nova_scenario/src/actions/mod.rs`	`EventConfig`, `EventFilterConfig`, `EventActionConfig`	One dispatch enum each; actions fan out to the flow/mission/sequence/ship/spawn/timer/view submodules beside `mod.rs`.
Scenario variables, expressions, watches	`nova_scenario`	`crates/nova_scenario/src/variables.rs`, `crates/nova_scenario/src/world.rs`	`VariableExpressionNode`, `NovaEventWorld`	Typed literals + expression tree (`VariableConditionNode` for filters); watches sample typed world queries into variables.
Scenario objects (asteroid, planet, spaceship, beacon, crate, light, anchor)	`nova_scenario`	`crates/nova_scenario/src/objects/mod.rs`, `crates/nova_scenario/src/actions/spawn.rs`	`ScenarioObjectsPlugin`, `ScenarioObjectKind`	One module per kind under `objects/`; the spawn action dispatches on the kind enum.
Scenario loading, lifetime scoping, teardown	`nova_scenario`	`crates/nova_scenario/src/loader/mod.rs`, `crates/nova_scenario/src/loader/lifecycle.rs`	`ScenarioLoaderPlugin`	`LoadScenario`/`UnloadScenario` observers; everything tagged `ScenarioScopedMarker` dies at teardown; `scenario_is_live` gates the ship sets.
Mod formats, bundles, portal	`nova_mod_format`, `nova_modding`, `nova_assets`	`crates/nova_mod_format/src/lib.rs`, `crates/nova_modding/src/lib.rs`, `crates/nova_assets/src/portal/mod.rs`	`BundleManifest`, `Content`, `PortalPlugin`	Engine-free serde wire types -> RON asset loaders -> portal fetch/verify/install. The static portal is generated by `scripts/gen-portal.py` over `webmods/`.
Content generation (base RON, builders, lint)	`nova_authoring`	`crates/nova_authoring/src/cli.rs`, `crates/nova_authoring/src/generation.rs`	`cli::main`	`cargo run content gen` serializes the `base_content` builders into the committed base `*.content.ron`; `content lint` validates any content tree. Never hand-edit generated RON.

Interface

Concept	Crate(s)	Key files	Entry symbol	Orientation
The TAB interface and the `;` command modal	`nova_command`, `nova_interface`	`crates/nova_command/src/commands.rs`, `crates/nova_interface/src/pane.rs`, `crates/nova_interface/src/lib.rs`	`InterfacePlugin`, `InterfaceSystems`, `CommandsSystems`	Pure command language and terminal model in `nova_command` (`COMMAND_CATALOG`, `CommandTerminal`); the Tab interface with its Map, Ship and Inventory panes, and the `;` CRT modal, in `nova_interface`.
Keybinds: the action table, rebinding, the capture	`nova_input`, `nova_menu`	`crates/nova_input/src/registry.rs`, `crates/nova_input/src/poll.rs`, `crates/nova_menu/src/settings.rs`	`InputBindings`, `InputSources`	One table of named actions; each owner registers its own defaults, every rig is BUILT from it, and every rebind surface reads it. Settings’ Controls tab takes the next press through `InputSources`; overrides persist in `settings_store`.
Flight HUD widgets	`nova_hud`	`crates/nova_hud/src/lib.rs`	`NovaHudPlugin`	One module per instrument (crosshairs, ammo, markers, comms, keybind dock); reads the ship, never drives it.
Main menu, menu backdrops	`nova_menu`	`crates/nova_menu/src/lib.rs`, `crates/nova_menu/src/ambience.rs`	`NovaMenuPlugin`	The backdrop is a `role: Backdrop` scenario from the menu’s shuffled rotation (`MenuBackdropRotation`); a backdrop’s `BackdropDone` makes `advance_menu_backdrop` cut to the next one. `NOVA_MENU_BACKDROP` pins the first one for capture.
Training handbook: lessons, field notes, progress	`nova_training`, `nova_menu`	`crates/nova_training/src/catalog.rs`, `crates/nova_training/src/validate.rs`, `crates/nova_menu/src/training.rs`, `crates/nova_menu/src/training_store.rs`	`TrainingCatalog`, `TrainingProgress`	A lesson is CONTENT (`Content::Lesson`): `register_bundles` merges base + mods into `TrainingCatalog`, and the menu draws whatever it is handed. Practice may only name a `role: Lesson` scenario and `proven_by` any launchable one; both are `lint_lesson`, at lint and then at load. Progress is a SECOND file beside `settings.ron` (`TrainingProgressPlugin`): opening a lesson reads it, and only a Victory on a scenario its `proven_by` names completes it. Field notes are derived from the same lessons (`facts.rs`) and drawn on three surfaces - the menu’s bottom-left notice corner beside the first-launch offer, the boot screen (compiled `boot_field_notes`, before any catalog exists) and the scenario load screen, which prefers a note from a lesson that names the scenario. Each corner notice carries its own switch (`TrainingPromptSetting`, `FieldNoteSetting`): the card writes it, Settings > Interface brings it back, and neither touches the loading screens. A lesson’s demonstration is real footage at `assets/base/training/<id>.webp`, recorded by the `lesson_*` capture producers (`scripts/capture-lesson-media.sh`) and cut by the grid the LESSON authors; every base lesson has a producer, and one authored without one keeps `scripts/gen-lesson-media.py`’s placeholder, which never redraws over captured footage.
Scenario roles	`nova_scenario`	`crates/nova_scenario/src/loader/mod.rs`, `crates/nova_scenario/src/lint/scenario.rs`	`ScenarioRole`	`Chapter` (a level, the picker row), `Backdrop` (menu scenery, poses its own camera, reports `BackdropDone`), `Lesson` (a handbook practice range). A campaign may list only chapters that need no New Game session.
Station visits and trade profiles	`nova_world_base`, `nova_gameplay`	`crates/nova_world_base/src/station_visits.rs`, `crates/nova_gameplay/src/station_visits.rs`, `crates/nova_gameplay/src/trade_profile.rs`	`StationVisits`, `TradeProfileDesign`	`drive_station_visits` is the one writer of `StationVisits`: a generated AI ship with a profile binds a nearby living station, docks, runs its trades and posts its jobs once (the receipt), then departs. A profile is content (`GameTradeProfiles`); the trade plans against both holds and purses and never creates cargo or credits.
Scenario world	`nova_scenario`, `nova_world_base`	`crates/nova_scenario/src/loader/mod.rs`, `crates/nova_world_base/src/lib.rs`	`ScenarioWorldType`	`Void` (the default: authored objects only) or `Generated((seed, bounds))`: the base generator streams around the scenario’s one player ship. `seed: None` takes the New Game seed (`OpenWorldSession`), so only New Game and Load start it; a fixed seed is a picker row.
Shared UI themes and widgets	`nova_ui`	`crates/nova_ui/src/theme/mod.rs`, `crates/nova_ui/src/widget/mod.rs`	`NovaUiPlugin`	Moddable UI themes (`UiThemeConfig` -> `ActiveUiTheme`) and the widget factories every UI-drawing crate consumes.
Ship editor, link points, placement	`nova_editor`, `nova_ship`	`crates/nova_editor/src/lib.rs`, `crates/nova_editor/src/snap.rs`, `crates/nova_ship/src/sections/link_points.rs`	`NovaEditorPlugin`	Editor build scene; `snap_placement` mates socket frames; the editor solver decides or refuses a drop.
Mod project, Mod Hub, package, import, asset bench	`nova_editor`, `nova_assets`	`crates/nova_editor/src/project.rs`, `crates/nova_editor/src/asset.rs`, `crates/nova_editor/src/project/store.rs`, `crates/nova_editor/src/project/package.rs`, `crates/nova_editor/src/ui/hub.rs`	`ModProject`	One mod held in memory: `KINDS` lists its content, one asset is open, `package.rs` owns the zip and the import checks.

Tooling

Depth: Automation harness, Measuring performance and Building and running.

Concept	Crate(s)	Key files	Entry symbol	Orientation
Automation harness, autopilot scripts, screenshot capture	`nova_autopilot`, `nova_debug`	`crates/nova_autopilot/src/autopilot.rs`, `crates/nova_debug/src/harness.rs`	`AutopilotPlugin`	Env-armed step driver (`NOVA_AUTOPILOT`, `NOVA_CAPTURE`); Nova presets and the `shoot` capture idiom live in the debug harness module.
Probe, run reports, what an example claims	`nova_probe`, `nova_probe_cli`	`crates/nova_probe/src/capabilities/mod.rs`, `crates/nova_probe/src/contract.rs`, `crates/nova_probe_cli/src/native.rs`	`NovaProbePlugin`	One bundle wires every capability; `probe run`/`scenario`/`report` (subcommands of the game binary, `debug` feature) spawn and grade runs. Web capture app: `crates/nova_perf_web/src/main.rs`.
Frame cost, scene census, the capture window	`nova_probe`	`crates/nova_probe/src/capabilities/frametime.rs`, `framecost.rs`, `census.rs`	`nova_frametime`, `nova_framecost`, `nova_census`	Wall-clock deltas over a fixed window, plus where the milliseconds went and what the scene contained. Knob table: `cargo doc -p nova_probe`.
World-state snapshot (read the world, not a render)	`nova_probe`	`crates/nova_probe/src/capabilities/snapshot.rs`	`nova_snapshot`, `probe_snapshot`	One JSON object per snapshot: ships, sections, fixtures, weapon state, rounds in flight. Sorted and rounded, so two snapshots of one frozen frame are byte-identical.
WFC arena: benching generated hulls	examples, `nova_wfc`	`examples/playable/wfc_arena.rs`, `examples/playable/wfc_arena/stamps.rs`	`arena_tiles`	Fields collapsed hulls against each other. The collapse itself is `nova_wfc` (see The ship); the arena names a spinal gun as its plan’s `keel.bow_gun` and stamps a large-drive stern no single plan can express. Lobby, pause and result flow sit beside it in `examples/playable/wfc_arena/`.
Debug tooling (Nova Debug window, overlays, F12 screenshots)	`nova_debug`	`crates/nova_debug/src/lib.rs`, `crates/nova_debug/src/hud/mod.rs`	`DebugPlugin`, `DebugHudPlugin`, `DebugOverlays`	Compiled only under the `debug` feature; F11 opens the Nova Debug window (freezes flight in `PauseStates::Debug`), F12 screenshot, `--norender`, `--debugdump`.
Web preview, this book at /dev/	scripts, web	`scripts/serve-web.sh`, `scripts/preview-web.sh`, `web/webpack.config.js`	`serve-web.sh`	Live-serves site + `/play/` + `/mods/` + this book at `/dev/`, all watched; the preview script builds the static deploy shape.