Orders and eligibility layers

Section titled “Orders and eligibility layers”

The game database as shipped holds two boarding actions in DIM_MoveAction, “Attempt Boarding Action All Formations” (MoveActionID 145) and “Attempt Boarding Action” (MoveActionID 146). Both use requirement 74 (MoveRequirementID 74) and allow a contact destination (Contact = 1). The single-formation action has DestinationItemType 5, so the player picks one of the formations the fleet carries. The all-formations action has DestinationItemType 0 and shows no item list. When the fleet works out how long its orders take to unload, both actions count zero unloading time. Being offered the order does not mean that a chosen formation can launch or survive. The move action catalogue lists both rows with their other flags.

The fleet meets requirement 74 when a ship class has TroopCapacity above 0 and its troop transport technology is “Troop Transport - Boarding Equipped” (DIM_TechType ID 207). For a given destination, the order list of the Naval Organization window also needs an existing contact of the ship type . That list does not check embarked troops, their infantry make-up, or the speed, hostility or armour of the target.

NPR engagement can queue boarding ahead of ordinary weapons fire. It does so when the fleet has a ship with boarding-equipped troop transport technology whose ship AI rates it fully capable for its role, and any formation aboard any ship of the fleet. These need not be the same ship. The NPR queues the all-formations action against a ship contact directly, without the order list filter of the Naval Organization window. The NPR tactical and system behaviour page covers the rest of that engagement choice.

Boarding behaviour depends on the race that gave the order. Other races use the ordinary troop transport dispatch. The order is marked completed after either one, whatever the launch outcome. Ordinary dispatch visits each ship of the fleet that has at least one undamaged troop transport component, and it launches only from ships that have no mothership. It does not repeat the boarding-equipped technology check. The single-formation launch takes the formation chosen in DestinationItemID, adds its subordinate formations when the order’s LoadSubUnits option is set, and launches each one only when it is actually aboard this ship. The all-formations launch tries every formation aboard this ship, with no infantry, race or status filter of its own.

The boarding attempt first needs an existing contact that is a ship. A missing contact or a contact that is not a ship ends the attempt with a Boarding Attempt event (event names are rows of DIM_EventType). The attempt then rejects a target whose current fleet speed is above the launching ship’s fleet speed, and it rejects a formation that holds any element that is not infantry. Equal speeds are allowed. Neither step has a test of its own for range, same system, hostility, faction, boarding technology or whether the target is already being boarded. Arrival at the destination and the choice of order are separate, earlier steps. These missing tests do not mean that every such attempt can be ordered through the ordinary order list.

Launch transit and interception losses

Section titled “Launch transit and interception losses”

For each formation element, let r = launching fleet speed / target fleet speed, as a fractional number. The survival threshold per unit on a d1000 is T = 100 x r. It doubles when the element’s unit class has the Boarding Combat capability (DIM_GroundUnitCapability ID 1). The capability’s numeric value plays no part. When T is 1000 or more, the element skips the transit rolls entirely. Otherwise each live unit rolls a d1000 and is lost when the roll is above T. At equal nonzero speeds, ordinary infantry have 100 surviving faces and boarding specialists 200. This is an abstract speed-ratio loss. Ship weapons and point defence take no part in it.

A stationary target with a moving launcher gives an unlimited ratio, so the element skips the losses. When both fleets are stationary, the ratio has no defined value. Neither “T is 1000 or more” nor “roll above T” holds, so no unit is lost in transit. An element whose class has HQ capacity (HQCapacity above 0) and that takes losses exposes the formation commander to a roll of d(original element Units) at or below the number of units lost. On a casualty the commander gains the history line “Killed during a boarding attempt on” followed by the target name and retires with the status “Killed during Boarding Combat”. The commander lifecycle page covers retirement.

Partial losses subtract Units at once. Losing an entire element removes it and removes the formation’s connection to its ship, even when other elements remain. A later element of the same formation that also takes losses needs that ship for its loss message. The attempt then shows a Function #1767 error and ends for that formation. The attempt reports one of two outcomes to the launch. When no elements remain at the end, the outcome is “formation lost”. Otherwise the formation becomes boarded (BoardingStatus 1), its connection moves to the target ship, and the outcome is “not lost”. “Formation lost” therefore means complete loss, not successful boarding. “Not lost” also covers rejected attempts and attempts ended by an error.

On “formation lost”, both launches log “All units of” the formation “were lost in a boarding attempt launched from” the formation’s ship, before they remove the formation from the game. The loss of the last element can already have cleared the formation’s connection to its ship. The message then fails. The launch shows a Function #2782 error (single formation) or #2783 (all formations), and that ship’s launch ends there before the formation is removed. A formation can also be left partly changed when a later step of its attempt fails.

Boarding clock and hull breach

Section titled “Boarding clock and hull breach”

When the selected increment is longer than 5 seconds and some ship hosts boarded formations of another race, the increment can be shortened to 60 - highest boarding clock, taking the highest boarding clock (FCT_Ship.BoardingCombatClock) among those ships, but never below 5 seconds. It is shortened only when that value is less than the selected increment. This targets the 60-second combat point, not the 30-second charge point. The boarding update runs with the increment length after planetary ground combat processing, and it does not need a planetary combat round to be due. Game time and state refresh covers the other reasons an increment is shortened.

The boarding update first clears the increment’s combat attack records, even when there are no boarders. When boarded formations exist, it returns two kinds of formation to not boarded, boarded formations that have no ship and every formation aboard a ship of its own race. It then rebuilds the list of boarders. For each boarded ship, all remaining boarding races form one attacking side. The defender’s race is forced into hostility with each boarding race it does not already treat as hostile. Mutually hostile boarding races are not split into separate fights. The ship’s clock gains the entire increment once. Boarding timing before capture describes the same steps from the ownership side, with the diplomatic change.

Hull access and clock handling run in this order:

State on entry Result
No armour damage entries Hull open only when the class NoArmour flag is not 0
At least one armour damage entry Hull open when the deepest damage is at least ArmourThickness
Closed hull, clock below 30 Boarding Underway event to each boarding race, saying a breaching charge is being prepared and is ready in 30 - clock seconds. The ship’s pass ends
Closed hull, clock 30 or more Reset the clock to 0, add one point of armour damage, report the detonated charge. The ship’s pass ends
Open hull, clock below 60 Report to both sides that the hull is penetrated and combat is underway. The ship’s pass ends
Open hull, clock 60 or more Reset the ship’s combat tracking and the clock to 0, then look at the defenders and the capture test

The first charge picks a column with d(ArmourWidth) and gives it damage 1. Later charges add 1 to the column with the most damage. A charge that opens the hull still ends that pass without fighting or capture. At most one charge or one combat and capture opportunity happens per ship per update. The reset to 0 discards any seconds above the threshold. A long increment does not count several charges or rounds.

Defenders and temporary crew

Section titled “Defenders and temporary crew”

At an open-hull pass whose clock has reached 60, the defenders are every formation of the ship’s race whose ship is the target or whose ship has the target as its mothership. Defenders need not be infantry. Troops of other races aboard carried ships are left out. The attackers are the boarded formations directly aboard the target.

If there are no defenders and CurrentCrew is exactly 0, the ship is captured before any attack. Otherwise the update asks for a temporary crew formation. None is created when CurrentCrew is 0 or less. The update then sets CurrentCrew to 0 and moves on to the next ship. Consequently zero crew plus surviving embarked defenders skips the entire fight. The embarked troops do not fight alone, and capture cannot happen while their formations remain.

The crew unit class is Infantry, with Light Infantry Armour (DIM_GroundUnitArmour ArmourTypeID 10) and Light Personal Weapons (DIM_GroundComponentType ComponentTypeID 27). Its armour strength modifier (ArmourStrengthModifier) is halved after creation. The class is named “Crew” and does not join the race’s list of ground unit classes. The temporary formation takes the ship’s display name and the abbreviation “CREW”. It uses the ship’s race, no population, parent or templates, the race’s first ground forces commander rank as its required rank and no assigned commander. Its one element has Units = CurrentCrew, Morale = CrewMorale x 100, the ship’s species and a flag that marks it as the ship’s crew. Each creation uses up a new formation ID. The formation joins the game’s formations for the round so that the shared aftermath can process it. Afterwards the remaining units become CurrentCrew and element Morale / 100 becomes CrewMorale. When the element list is empty, CurrentCrew becomes 0. The temporary formation is then removed.

Attack sequence targeting and fire

Section titled “Attack sequence targeting and fire”

Each round that is fought runs the attackers against the defenders with a target defence divisor of 2, then the defenders against the attackers with a divisor of 1. It records the combined collateral and then runs the shared aftermath with troop transport casualties skipped. Both sides therefore fire before pending unit losses apply. Each phase takes the offence or defence multiplier from each formation’s own commander (the ground combat offence or ground combat defence bonus), or 1 when the formation has no commander. This is not the HQ chain allocation of planetary combat described under HQ capacity and command bonuses.

The phase also builds selection intervals per formation, but the actual target comes from one flat list of all defending elements. Each element’s weight is whole-number(Units x class Size), with an inclusive interval that starts at previous total + 1. No weight reduction for non-combat classes applies here. Every attacking unit rolls d(total element weight) once and keeps that element for all its component shots. A zero-weight element has an empty interval. When the whole pool has weight 0, no element can be selected. The attacking element’s fire then fails with a Function #1809 error, and that element’s attacks in the phase end there with no collateral score.

The hit threshold on a d10000 is:

H = B x (Morale / 100) x offence x specialist / (noncombat x phase divisor x target defence)

B is the base ground hit chance of 2000. Morale is the attacking element’s. Offence is the attacking formation’s multiplier and target defence is the multiplier of the target element’s formation. Specialist is 2 when the class has the Boarding Combat capability, otherwise 1. Noncombat is 5 for a class with NonCombatClass set, otherwise 1. Each component of the attacking class with a modified penetration above 0 fires all its Shots. Modified penetration and damage are the component’s Penetration and Damage multiplied by the class WeaponStrengthModifier and rounded to two decimals. A shot hits when d10000 is at most H. H does not compound across shots. Boarding fire uses no supply and has no gravity, pressure or temperature test and no terrain or fortification modifier.

Each hit uses the shared ground incoming-hit model. When armour A is greater than the penetration AP, penetration needs d100 at most 100 x (AP / A)². Otherwise penetration is automatic. When hit points HP are greater than the damage, a kill needs d100 at most 100 x (damage / HP)². Otherwise the kill is automatic. Surviving units keep no partial damage. Element attacks and damage gives the class armour and hit point rules. The class sizes destroyed by an element’s fire are recorded as a Ground Tonnage Destroyed measurement for the attacking formation’s commander.

Deferred casualties morale and aftermath

Section titled “Deferred casualties morale and aftermath”

Incoming hits add to the element’s pending hits, penetrations and units lost this combat instead of subtracting live Units. Repeated kills can exceed the target’s count, and the target’s full count before the aftermath can still return fire. Boarding applies the front-line morale rule. A kill against a formation in the Front Line Attack field position (FieldPosition 1) changes defender morale by -Morale / Units / 2. Any other position gives -Morale / Units / 4. The attacking element gains 1 / (5 x target Units) morale points in the first case or 1 / (10 x target Units) otherwise. These use the live count and morale, not a count reduced hit by hit. Boarding itself has no morale-based surrender check.

A kill on an HQ unit can retire its formation commander at once with the status “Killed in Ground Combat”. With h = this class's HQ maximum size (HQMaxSize) and C = sum over the formation of live Units x class HQ maximum size, the test is a strict d1000 below 1000 x (h / C) x 0.25. For a formation aboard a ship, the casualty message and history take the ship’s name from the commander’s race’s records of known alien ships. The same lookup is used when the defender is aboard its own ship. The game has no separate message for that case.

The shared aftermath produces the attack reports. It caps pending hits, penetrations and losses at the live Units, removes destroyed elements and empty formations, and subtracts the losses of surviving elements. It applies pending morale only when its size is above 0.1 and units remain, with no limit on the result in this step, and then resets the pending counts. In boarding, the aftermath skips the ordinary troop bay capacity casualties. It does not prevent every casualty from ship damage. Reports and deferred aftermath describes the same aftermath for planetary combat.

Collateral and external ship damage

Section titled “Collateral and external ship damage”

Every boarding shot that is fired adds the raw component Damage cubed to a collateral score, whether it hits or misses. The score includes both sides and uses the unmodified damage, separately from the modified penetration and damage used against units. The collateral step divides the total score by 10000 and takes the whole-number part. It adds one more when d100 is at most whole-number((scaled score x 100) modulo 100), so the fractional part becomes a percentage chance of one extra point. A nonzero result becomes one collateral hit of that damage, credited to the first boarding race. It resolves through the ordinary incoming ship damage of space combat resolution, so it can destroy the boarded ship.

Component destruction can remove crew and troops on its own while boarding is under way. For a class with crew, the ordinary crew loss is the component’s crew x (0.25 + 0.05 x d10), rounded down, and capped at CurrentCrew - 1. When any boarded formation is directly aboard, the destruction also picks those boarders plus the ship race’s not-boarded formations directly aboard. It starts with f = destroyed component size / ship class Size. For each formation in turn, it multiplies the current f again by 0.25 + 0.05 x d10, then subtracts whole-number(element Units x f) from each element at once. The factor therefore compounds across formations. Defenders aboard parasite ships are not in this list of formations directly aboard.

These immediate troop losses add no pending hits or morale, and they do not remove elements or formations that reach zero units. Collateral can reach this component step although the aftermath skips the ordinary bay capacity casualties. Immediate component casualties and deferred losses from boarding shots are distinct mechanisms with different cleanup. Internal component allocation and death covers how a component is chosen and destroyed.

Capture timing and ownership transfer

Section titled “Capture timing and ownership transfer”

Capture is tested before the crew formation is created or anyone fires, and only after the hull is open and the clock has reached 60 seconds. Eliminating the last defenders during a round does not transfer the ship in that round. A later qualifying pass must find no defending formations and CurrentCrew exactly 0. The race of the first boarding formation wins. There is no strength comparison or vote among the boarding races.

The capture refreshes the captor’s alien class record from the actual class and shows the portrait. It logs a Boarding Combat event for each side, “has been boarded and captured by” for the old owner and “Our forces have successfully boarded and captured the alien ships” for the captor. It then runs the old race’s shared ship transfer to the captor with known names, and no destination fleet. After the transfer it sets OverhaulFactor to 0.01, the same value that ship surrender sets. It sets LastShoreLeave to current time - 2 x new class PlannedDeployment x 2592000 seconds (2592000 seconds is one month), so the prize starts with a deployment age of twice its planned deployment. It sets CurrentCrew to 1 and crew casualties to 0. A class that is not commercial gets CrewMorale 0.25. A commercial class keeps its morale. Every active commander who commands one of the listed boarding formations records 1 for the Successful Boarding Combat measurement, which the boarding medal conditions count. When the captor has no class or hull record for the ship, the update shows a Function #1816 error and the boarding update ends there.

The boarders are not used up or reassigned. After the transfer, formations of the winning race aboard their own new ship return to not boarded at the next boarding update. Boarders of other races can remain aboard as hostile occupants. Ship readiness and recovery explains what the low overhaul factor, crew morale and shore leave values do afterwards.

The shared ship transfer makes these connected changes:

Area Transfer behaviour
Class When a player race captures an NPR ship, the original class name can first be overwritten with the name from the captor’s alien class record. The transfer reuses the first class in the game whose OtherRaceClassID equals the original class ID, without checking that this class belongs to the captor. Otherwise it copies the design to the captor and recalculates it. The selected class is locked (Locked).
Identity Set the selected class, the captor race and the captor’s primary species, then disembark the officers with the crew grade credit. Clear the shipping line and the ship’s tow target. When known names are requested, use the captor’s known name for the ship when it has one.
Original troops Formations of the source race directly aboard move to a source-race population at the ship’s coordinates when one exists. Otherwise their commanders lose their assignments and the formations are removed. Boarding troops of other races keep their links.
External references Clear the tow target of other ships that tow this one. Clear trade goods cargo. Remove the shipyard tasks for this ship, its tracking contacts and every race’s remembered alien hull record for it. This is not a blanket clear of all fuel, cargo or ordnance.
Fleet and AI An NPR captor creates ship AI for the ship and works out its automated design role. Colony ship, liner and freighter designs take the captor’s first shipping line and force a fresh fleet. With no destination fleet, a fleet is created at the captured ship’s coordinates, in Reinforcement Group (ID 11) or Civilian (ID 18, for a ship with a shipping line) for another NPR, and no operational group for a player. The transfer clears the squadron assignment, cancels tasks, removes an empty source fleet and recalculates both fleet speeds.
Carried ships Transfer every ship whose mothership is this ship to the destination fleet, each in turn with the same steps. For a player captor, clear the NPR ship AI and the destination fleet’s standing orders.

Commander handling happens after the ship’s race has already become the captor. The disembark step collects the commanders the ship transports, its assigned commanders and its officers in the captain, executive officer, chief engineer, science officer, tactical officer and CAG roles. It clears their assignments and transport ship and places them at a local captor population when one exists. When GradePoints are above the base crew grade of 100, it also credits the captor’s AcademyCrewmen with whole-number(CurrentCrew x GradePoints / (100 x captor TrainingLevel)). It does not reset the prisoner flag (Prisoner). These steps do not keep all original officers aboard the prize. The commander lifecycle page covers academy crew.

Surrender as a separate entry path

Section titled “Surrender as a separate entry path”

Ship surrender has no eligibility test of its own. It refreshes the captor’s class record and portrait and logs the surrender for both sides. It records the original race, species and CurrentCrew as a survivor group linked to the ship (saved in FCT_Survivors). Each officer in a ship command role gets the history line “Surrendered to” the captor, loses the assignment, takes this ship as transport ship and is marked a prisoner (Prisoner true). Ship surrender then runs the same ownership transfer, adds the survivor group, and applies the same one-crew and readiness reset as boarding capture (OverhaulFactor 0.01, LastShoreLeave at current time - 2 x PlannedDeployment x 2592000 seconds, CurrentCrew 1, crew casualties 0, and CrewMorale 0.25 for a class that is not commercial). The shared disembark step can then clear the officers’ transport ship and place them at a local captor population, so the earlier transport assignment does not guarantee they stay aboard. Forcible boarding capture does not create this surrendered-crew survivor group. When a step of ship surrender fails, it shows a Function #2714 error and ends there. Surrender adds prisoners before the same transfer gives the order of these steps, and prisoners and interrogation covers what happens to the survivors later.

The tactical NPR decision has narrower conditions than ship surrender itself. With recent hostile ships and known hull records for them, it considers fleets damaged less than 120 seconds ago. It needs a ship of the fleet hit by a beam weapon less than 120 seconds ago and a compromised state, meaning no nearby combat-capable friendly ships, mission availability Unavailable, system readiness Inoperable or missile ordnance Empty. Nearby means that both coordinate differences are strictly below 1,000,000 km. Combat-capable means ProtectionValue above 0 and a ship AI role capability above Incapable. fleets marked NoSurrender choose ramming instead, and they exclude enemy ships that already hold one of their own formations.

Other fleets decide only when their last surrender decision is strictly older than current time - 120 seconds, and the decision time is then updated. Let D be the highest Determination and X the highest Xenophobia among the species of the fleet’s ships. The two maxima can come from different species. The surrender threshold is (200 - D - X) / 10, tested with a strict d100 below the threshold, and it also needs zero nearby combat-capable ships. The race of the nearest recent hostile fleet, measured through Lagrange points, receives every ship of the fleet. If surrender fails, a separate strict d100 below (D + X) / 10 can set FCT_Fleet.NoSurrender for good.

The population control transfer orders ship surrender at two separate points. When forced local ship surrender is on and the population amount (PopulationAmount) is 10 million or more, the old owner’s ships in the same system at exactly the population’s coordinates surrender. When the old owner is a Standard NPR whose total population equals this population’s amount, so that this is its last population, its remaining ships at the same location surrender when their automated design policy allows it. That policy (DIM_AutomatedClassDesign.SurrenderStatus) is 0 for never, 1 for always, 2 for only heavily damaged (role capability Incapable), or 3 for heavily damaged or out of ammunition (Incapable, or missile ordnance Empty). Tactical refusal by a special faction is not a check inside ship surrender. Wider conquest rules remain under surrender and occupation strength.

boarding operations

Section titled “Swarm boarding operations”

Persistence and reload

Section titled “Persistence and reload”

The game stores each formation in FCT_GroundUnitFormation with RaceID, ShipID, PopulationID, BoardingStatus, FieldPosition and the ordinary parent and template links. Loading restores race and status and links the ship by ID. Only records with a nonzero ship or population ID join the game’s formations. BoardingStatus has only two values, 0 for not boarded and 1 for boarded. No separate breaching stage is stored. Hull damage plus the ship’s clock decide the next stage.

FCT_GroundUnitFormationElement stores Units, SpeciesID and Morale. FCT_Ship stores BoardingCombatClock, CurrentCrew, CrewMorale, OverhaulFactor, LastShoreLeave, RaceID, SpeciesID, ShipClassID, FleetID and the mothership (MothershipID), tow (TractorTargetShipID) and squadron (ParentSquadronID, AssignedSquadronID) links. An ordinary save and load therefore keeps the boarders’ location and status and the accumulated clock. The temporary crew formation is normally removed after its values are copied back to the ship. The pending casualty and morale counts of a round are not stored in these columns. Persistence and reload boundaries covers what a captured hull keeps.

Worked examples

Section titled “Worked examples”

These are synthetic calculations, not recorded battles.

Transit survival. With both fleets moving at 4000, r = 1. Ordinary infantry survive on d1000 rolls 1 to 100, and specialists survive on 1 to 200. A specialist at a launching speed of 10000 against a target speed of 2000 has T = 1000 and makes no transit rolls. Ordinary infantry need r of at least 10 to skip them. These are thresholds per unit, not a promise of a particular surviving headcount.

Breach and delayed capture. Assume a clock of 0, an intact hull three layers thick and consecutive qualifying updates of 30 seconds. Three charge passes each add one damage to the chosen column and reset the clock, including the pass that opens the hull. Another two updates of 30 seconds reach the 60-second open-hull opportunity. If that round kills the final crew and all defenders, ownership still waits for a later 60-second pass with an empty defender list. Real increments can space the charges further apart, because increment shortening aims at 60 seconds, not 30.

Fire and collateral. A specialist at Morale = 100, offence = 1 and target defence = 1 has H = 2000 as a boarder (2000 x 2 / 2), or H = 4000 as a defender (2000 x 2 / 1). Ten eligible shots in total with raw Damage = 10 give a score of 10 x 10³ = 10000 and exactly one point of collateral damage after scaling, whatever their hits and modified weapon damage.

Deferred losses and the zero-crew stall. An element with Units = 10 can collect 12 pending losses while still returning fire with 10 units. The aftermath caps the loss at 10 and removes the element. If that was the crew but an embarked defending formation survives, the next qualifying pass finds defenders, cannot create a crew formation at CurrentCrew 0 and moves on without either side firing. It does not resolve the remaining troops as a fight without crew.

At a speed ratio of 2, capacity is 8 for a military target or 80 for a commercial one. A commercial target of Size = 40 gives Round(40 / 80) = Round(0.5) = 0 committed transports, because an exact half goes to the even neighbour. Nothing raises that to one before the Recycling fleet is created.

Concept map

Section titled “Concept map”

Resources

Section titled “Resources”

Related community documentation and developer posts. These may describe a different game version.