Defensible

A Defensible is the X4 engine abstract class for objects that defend themselves — has shields, turrets, weapons, can be boarded, has loadouts. Inherits from Controllable and is parent of Container (stations) and Ship (mobile).

Inheritance: object → controllable → defensible. Subclass: Container (most stations), Ship (mobile combat entities).

Properties

Boarding + capture

Critical for boarding mechanics:

Property	Type	Description
.iscapturable	boolean	Can this be captured (signalleak S/M or boarding L+)? Also: S-ship pilot won’t eject if false.
.isalertlevel.<level>	boolean	At alert level (red/yellow/green). Note: Turrets deactivate on green.
.boardingoperation	operation	Current boarding operation this object is part of
.boardingoperations	list	Inbound boarding operations to defend against
.boardingbehaviour	boardingbehaviour	Boarding behaviour assigned for current operation
.boardingmarines.count	integer	Total marines assigned for boarding
.boardingmarines.combinedskill	integer	Combined marine skill 0-100
.boardingmarines.{$level}.count	integer	Marines at specific tier
.allmarinesdispatched	boolean	All marines dispatched?
.boardingresistance	integer	Total boarding resistance
.baseboardingresistance	integer	Base resistance defined for object
.boardingstrength	integer	Boarding strength of marines + officer

Shields / Turrets / Weapons

All defensive surface components share the same property pattern:

Property pattern	Type	Description
.shields.numslots / .turrets.numslots / .weapons.numslots	integer	Number of slots
.<X>.<state>.count	integer	Count filtered by state (all/construction/operational/wreck)
.<X>.<state>.list	list	List filtered by state
.<X>.<state>.indexof.{$component}	integer	Index of $component (1-based)
.<X>.<state>.random	shieldgenerator/turret/weapon	Random component

Where <X> is shields, turrets, or weapons.

Construction sequence

Property	Type	Description
.constructionsequence	constructionsequence	Current construction sequence
.hasstagedconstruction	boolean	Current/planned construction is staged
.hasfutureconstructionstage	boolean	Has future stages?
.planmodule.{$constructionplanentryid}	module	Module from construction plan entry
.requiresconstructionvessel.{constructionsequence}	boolean	Construction sequence needs construction vessel

Loadout overrides (ship/object loadout)

The loadout system controls equipment generation:

Property	Type	Description
.loadoutlevel	float	Loadout level used to generate this object
.rawloadoutlevel	float	Without fallback to parameters.xml
.minloadoutlevel	float	Minimum allowed (e.g. lowerbound in job definition)
.loadoutvariation	float	Loadout variation range
.moduleloadoutlevel	float	Module loadout level (station)
.rawmoduleloadoutlevel	float	Without fallback
.moduleloadoutvariation	float	Module variation

Plus quantity + quality variants:

Property pattern	Description
.loadoutquantity.level / .variation	Quantity overrides
.rawloadoutquantity.level / .variation	Without fallback (check -1)
.loadoutquality.level / .variation	Quality overrides
.rawloadoutquality.level / .variation	Without fallback (check -1)
.moduleloadoutquantity.level / .variation	Module quantity (station)
.moduleloadoutquality.level / .variation	Module quality (station)
.rawmoduleloadout...	Without fallback variants

The “raw” variants must be checked against -1 before use (signal that no override is in effect).

Defence drone mode

Property	Type	Description
.defencedronemode	dronemode	Current defence drone mode

Common access patterns

”Get all operational turrets on a ship"

<set_value name="$turrets" exact="$ship.turrets.operational.list"/>
<do_for_each name="$turret" in="$turrets">
    <write_to_logbook text="$turret.name"/>
</do_for_each>

"Check if a ship can be boarded"

<do_if value="$ship.iscapturable">
    <!-- can be captured -->
</do_if>

"Check if boarding operation is in progress"

<do_if value="$ship.boardingoperation?">
    <write_to_logbook text="'Boarding active!'"/>
</do_if>

"Find all shields on a station"

<set_value name="$shields" exact="$station.shields.all.list"/>

"Set ship to highest alert”

<set_alert_level object="$ship" level="alertlevel.red"/>

Common gotchas

• ⚠ Turrets DEACTIVATE on alert level green. Ships with green alert don’t fight back.
• ⚠ .iscapturable controls multiple things at once: signalleak capture (S/M) AND boarding capture (L+) AND S-ship pilot eject behavior.
• ⚠ The shield/turret/weapon state parameter is mandatory — <X>.list without state is invalid. Use .all.list, .operational.list, etc.
• ⚠ Raw loadout properties may return -1 — meaning “no override”. Check if $ship.rawloadoutlevel != -1 before using.
• ⚠ .boardingoperations (plural) is for DEFENDING side — .boardingoperation (singular) is the operation this object is in (attacking or defending).
• ⚠ Construction stages are managed via container subclass — defensible exposes the read API but not write.

Inheritance hierarchy

object
  └── controllable
       └── defensible              ← this class
            ├── container (stations)
            │    └── station (concrete)
            └── ship (concrete mobile)

Common actions

Action	Purpose
<set_alert_level>	Set object’s alert level
<initiate_boarding>	Begin a boarding operation
<cancel_boarding>	Abort boarding operation
<generate_loadout>	Generate a loadout (uses loadoutlevel, etc.)
<apply_loadout>	Apply a generated loadout
<evaluate_ammo_storage>	Evaluate ammo storage state
<add_ammo>	Add ammo to ammostorage (for deployables)

Related

• Controllable — parent class
• Container — child class (cargo/build/trade infrastructure)
• Ship — concrete mobile subclass
• Shield generator — .shields.*.list items
• Turret — .turrets.*.list items
• Weapon — .weapons.*.list items
• Boarding operation — .boardingoperation reference
• Loadout — what loadout properties control
• Architectural overview: Boarding — full boarding mechanic

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Defensible adds defense mechanics on top of Controllable. Most modders interact with it via ship.shields / station.turrets / boarding mechanics. The loadout properties are critical for procedurally-generated content.