Base defense response

Answers damage to a base by raising the owner's anger toward the attacker and calling a computer house's armed infantry and vehicles back to fight it.

Damage moves three separate mechanisms. Every house raises its anger toward the house that caused it — anger being a running figure each house keeps against every other house — and the house it holds the most anger toward is the one it treats as its declared enemy. Every house’s threat map records where each object stands, weighted by how dangerous its type is. Only a computer house runs the third: a call-up that empties its teams and sends armed infantry and vehicles back to the object that was hit.

That call-up is written in terms of teams and the definitions they are built from. A team is a group of infantry, vehicles and aircraft that one house owns and that acts together; a TeamType is the scenario section a team is built from, and it carries the settings a team is measured by. AI triggers and team production introduces both entities in full; the individual settings this page turns on are defined where they are used.

What counts as an attack

Two damage paths reach the call-up, and each hands it the object that caused the damage.

Damage to a structure

A building damaged by another object stamps the current frame on its house and runs the call-up, unless the building names an UndeploysInto vehicle and is not a construction yard — such a structure counts as a deployed vehicle rather than as part of the base. Both happen before any strength is lost and before the branches that end the damage routine early, so a hit absorbed entirely — by a laser fence, by an immune bridge repair hut, or by a firestorm wall draining it off the firestorm defense’s own charge — still counts as an attack on the base.

A protected object

ToProtect=yes puts the same call-up on the type’s runtime instances, for a computer house only. Any protected object of such a house is answered the same way, and a protected structure takes this call-up on top of the one every damaged structure already runs.

What the house announces

The announcement is a separate mechanism from the call-up. It is reached under all of the following:

the damage had a source;
some damage actually registered;
the damaged building does not set Insignificant=yes;
the damaged building is not a deployed vehicle.

What is then said depends on who is watching. A house under player control submits a radar event at the building’s cell and speaks the base-under-attack line. A house allied to the local player speaks the ally-attacked line instead, which outside a campaign additionally requires that the attacked house’s own country is not MultiplayPassive=yes. SpeakDelay holds off both lines and the radar event with them.

Every tag attached to a house then springs its attacked event, whichever house owns the building, and SpeakDelay does not hold that off.

The attacked state

A house is in its attacked state while the frame stamped by the most recent hit on one of its structures lies within the previous minute, and leaves it a minute after. Two decisions read it. While the state holds, a house never reports a fire-sale urgency — the judgment that a house still holding buildings, but none of them able to produce anything, should sell the whole base off at once — and a computer-owned aircraft on Guard stops looking for enemy vehicles caught outside any base.

The state is entered and left by the expert AI, the computer’s periodic decision pass, which re-arms itself with 7 to 7.5 seconds each time it runs and is also what fires a computer house’s superweapons. The stamp starts at frame zero, so every computer house that runs that pass begins the match in the attacked state and stays there for the first minute, before anything has been attacked. A MultiplayPassive=yes computer house never runs it and so never enters the state at all.

Anger and the declared enemy

Every house holds one anger figure for every other house, and never one for itself. Its declared enemy is whichever house it holds the most anger toward.

What raises it

Every damage event with a source raises the anger the damaged object’s house holds against the attacker’s house, by the damaged type’s build cost — for a structure, its Cost less any free unit it comes with and less any aircraft share bundled into it — scaled by the fraction of its Strength the hit removed, truncated to a whole number. The figure uses the damage that was actually applied — after armor, after distance falloff, and after a killing blow has been cut back to the strength that was left — so a hit worth less than one whole unit adds nothing at all. Healing is negative damage, so being repaired by a hostile healer takes anger back off.

This runs for every house, computer or human, allied or not, and it runs on damage to any object, not just to a structure.

How the enemy is chosen

The whole ledger is re-read on every one of those events. The house holding the highest figure becomes the declared enemy, provided it is neither defeated nor a current ally; a tie goes to whichever house was created first. A figure of zero never wins, and when nothing qualifies the declared enemy is cleared outright.

Defeated houses and allies are excluded from the choice but not from the ledger — their figures are kept and count again if the exclusion lifts. Allying with a house zeroes the anger held against it and drops it as the declared enemy; breaking an alliance adds one point of anger and rebuilds both houses’ threat maps. A computer house also clears the record of a declared enemy that has been defeated.

Decay

Every hundredth frame, each figure above one is reduced by one.

Picking a first enemy

A computer house adds one point of anger against another house under all of the following, tested in this order:

its AIHateDelays countdown has run out, which is seeded once as a multiplayer session is set up;
it holds no declared enemy;
the game is not a campaign;
its country is not MultiplayPassive=yes;
it has a base center, which it has only once its base is established.

The point goes to whichever other house has the nearest base center, counting only houses that are neither defeated nor MultiplayPassive=yes. The pick is not filtered by alliance, so picking a current ally raises a figure the choice above will still refuse to act on.

What the declared enemy drives

Whether a non-defensive AI trigger may be considered at all, and the house every trigger condition but one measures.
Which house the ion cannon rates objects from, and which house’s buildings the multi-missile and chemical missile choose between.
Whether the hunter seeker and the computer’s drop pods fire.
The preferred house for the two team missions that attack or move to a building with a named property.
EnemyHouseThreatBonus in target scoring, and the clamp a house ordered to hunt everything applies to anything outside the enemy’s ownership. Both belong to target selection.

The threat map

Every house keeps one figure per map region, and a region is a block of 4 by 4 cells. An object contributes its type’s ThreatPosed to every house’s map except its owner’s.

Each contribution is stamped across a 3 by 3 block of regions: the whole figure in the region the object stands in, half of it in the four regions beside that one, a quarter in the four corners, each step discarding its remainder. Taking a contribution back runs the same stamp as a subtraction, and every region floors at zero, so a region that has already bottomed out does not return what it was never charged and the two operations are not exactly reversible.

What adds and removes a contribution

Five events add a contribution or take one back. Because the stamp covers a 3 by 3 block of regions, each of them has to name one cell to center that block on, and the second column below is that cell rather than wherever the object happens to be standing. The last two rows are the ones that do not balance, and each is taken up by what follows the table: an ownership change stamps the contribution the wrong way round, and a visceroid merge is the one event here that adds a contribution nothing ever takes back.

Event	Cell the stamp is centered on
The object is placed on the map	The cell it appears in
The object leaves the map	For infantry, vehicles and aircraft, the last cell recorded for it; for anything else, its own cell
A ground object finishes moving into a cell	Credited at the new cell and debited at the old one, and only when the two fall in different regions
The object changes owner	Withdrawn under the previous owner’s identity and re-stamped under the new owner’s, at the same cell — so the previous owner’s own map gains the contribution and the new owner’s loses it
A small visceroid merges into a large one	Credited at the enlarged unit’s last recorded cell, with no matching debit

The owner exemption is narrower than it looks. A house skips its own objects always, and skips an ally’s objects only while that house is under human control — a computer house records its allies’ objects as threats along with everybody else’s.

Rebuilding the map

A house rebuilds its entire map in two situations only: when it forms an alliance, and — on both sides — when an alliance is broken. Outside a campaign every house is allied with the neutral Special house once every object has been placed, so every house’s map is rebuilt at scenario start; in a campaign those alliances are read before any object exists and nothing rebuilds. The map is otherwise purely incremental.

What reads the map

The multi-missile and the chemical missile each strike the enemy building standing in the highest-rated region.
A team that has begun to move and has fallen under strength is sent to gather at one of its house’s unarmed buildings, ranked by distance multiplied by the region’s figure plus one, and halved for a building that repairs vehicles.
The least-threat and greatest-threat building properties a team script can ask for.
The pathfinder, through ThreatAvoidanceCoefficient: a diagonal shortcut is refused where the region figure times the coefficient reaches 1, and a two-leg straight line counts each cell whose product reaches 0.01 as threatened and abandons the line once too many have accumulated. The hierarchical route planner prices a step from the regions it spans.

Calling defenders back

When the call-up is refused

The call-up ends before doing anything when any of the following holds, tested in this order. The whole table is about the damaged object and its attacker, not about the defenders: nothing here can be fixed by giving the house better troops, and the last row is the one that leaves a repeat attack by the same attacker unanswered.

Refused when	Detail
The attacker is an ally of the damaged object’s house
The house is under human control	Player control in a campaign, and a human player otherwise
The damaged object carries a primary weapon	Campaign games only — a base defense structure defends itself and pulls nobody back
The attacker is neither an infantry nor a vehicle	Aircraft and buildings never provoke a response
The damaged type sets `Insignificant=yes`
The attacker’s cooldown from an earlier response is still running	Below

The strength budget

The response is sized once, at the attacker’s ThreatPosed multiplied by ComputerBaseDefenseResponse in [AI]. An attacker whose type leaves ThreatPosed at zero produces a budget of zero and calls up nobody, whatever the multiplier is.

Anything already firing at the attacker is counted off that budget rather than added to the shortlist, at its own ThreatPosed. At the stock multiplier of 3, one such defender whose own ThreatPosed is three times the attacker’s takes the budget to exactly zero and cancels the response by itself. Exactly zero rather than below it is the distinction the cooldown turns on.

Teams are emptied first

Before any candidate is examined, every team the house owns is measured against one threshold. A TeamType’s Priority is the figure that settles which of two teams wins a member they both want; SuspendPriority in [General] is the level a team’s own priority has to reach to survive a call-up. Every team below it has all of its members removed and is suspended for SuspendDelay minutes — suspended meaning that the team takes no logic turn of any kind until that timer runs out.

The team object outlives the suspension, but it does not come back. A team carries a mark set the first time it ever reached full strength — the member count its TaskForce asks for, which is a roster figure and nothing to do with health — or the first time it was set in motion, and the mark is never cleared afterward. When the suspension expires, a team carrying that mark is deleted outright for having no members. A team that never earned it gets one pass at recruiting instead, and then falls to the ordinary rule that dissolves a team still empty a set number of frames after it was created, which applies outside a campaign only. Either way the members freed by the emptying carry no team for the rest of the same call-up, which is what makes them eligible below.

Which objects qualify

Infantry are walked first, then vehicles; aircraft and buildings are never candidates. Both passes stop the moment the budget is used up. Each candidate is rejected on the first of these that matches, so a candidate that survives the whole table is one that can reach the damaged object and hurt its attacker once it arrives. The rows fall into two halves: the first five ask whether the candidate is available at all, and the last three ask about this particular attack — the attacker’s armor, the ground in between, and whether the candidate has anything left to bring — none of which any amount of strength standing nearby can talk around.

Rejected when	Detail
It is inactive, or belongs to another house
It is on a team whose TeamType is not `IsBaseDefense=yes`	A team member that is already a base defender may be taken; any other team member may not
Its recruitable state, or its autocreate-recruitable state, is off	Both start set on every object
It carries no primary weapon
Its current mission sets `Recruitable=no`	Campaign games only
Its primary warhead’s `Verses` percentage against the attacker’s `Armor` is exactly `0%`
It is not in the same movement zone as the damaged object	The two destinations are compared, not the two positions, using the candidate’s `MovementZone`
It cannot bring any strength to bear	Below

A candidate brings nothing — a rating of zero, which drops it — under any of the following, tested in this order:

it is already attacking something that carries a weapon;
it is on a team whose TeamType is not IsBaseDefense=yes;
its mission is Harvest;
its own ThreatPosed is zero.

Otherwise its rating is ThreatPosed times 1024. That figure stands as it is when the attacker is already inside the candidate’s weapon range; when it is not, the figure is divided by the distance still to cover, measured in multiples of the candidate’s own top speed, and never falls below 1. A candidate already targeting the attacker rates minus its ThreatPosed instead, and that negative rating is what the budget is reduced by.

The shortlist and the orders

The shortlist holds six entries, shared between the two passes and filled in order. Once it is full, a stronger candidate is meant to replace the weakest entry, and the entry to replace is found by matching the stored ratings against a running minimum kept beside the list. That running minimum starts at zero and is updated only by a candidate examined after the list filled, so for one candidate it matches nothing the list holds.

The table walks eight candidates through the list with one illustrative set of ratings. The first six fill it and never touch the running minimum; the last two are the ones to read.

Candidate	Its rating	The shortlist after it	The running minimum after it
1	30	30	0
2	25	30, 25	0
3	40	30, 25, 40	0
4	20	30, 25, 40, 20	0
5	35	30, 25, 40, 20, 35	0
6	45	30, 25, 40, 20, 35, 45 — now full	0
7	50	unchanged: it beats the running minimum, but no entry holds `0`, so nothing is replaced	20
8	28	30, 25, 40, 28, 35, 45	25

Candidate 7 is the one that pays for repairing the running minimum: it clears the minimum of zero, finds no entry to overwrite, and its whole effect is to leave the minimum standing at the list’s true weakest figure. Candidate 8 is the first that displaces anything. Because infantry are walked before vehicles, six qualifying infantry therefore cost the first vehicle examined its place, and every vehicle after that one competes normally — which is how vehicles come to displace infantry that were admitted without being ranked against anything.

One further case keeps the list closed for longer. A candidate rated below the list’s own weakest entry leaves the running minimum at its own rating rather than the list’s, which again matches nothing, so the candidate after it is dropped as well; the running minimum settles onto the list’s weakest figure only once a candidate rated at or above that figure has been examined. And when more than one entry holds the running minimum, all of them are overwritten with the same candidate, so the list can carry one object several times.

The list is sorted from strongest to weakest and worked through in that order. Each defender takes the Rescue mission on a 66 percent chance and Area Guard otherwise; a member of an IsBaseDefense=yes team always takes Area Guard. Either way the damaged object is recorded as what the defender was sent to protect, and the attacker is assigned as its target.

A defender on Rescue engages whatever it finds near the damaged object and then heads for a cell its house nominates, settling into Area Guard when it arrives. An object with no offensive value at all is sent to the core of the base, a random point within one base radius of the base center. Everything else is sent to one of the four edge zones at random, an edge zone being the ground lying in one compass quadrant of the base between one and two base radii out from that same center.

Each defender’s ThreatPosed is subtracted from the budget after it has already been given its orders, so the first defender is always sent even when it alone covers the whole budget.

The attacker’s cooldown

Once the dispatched defenders have covered the budget, a countdown of BaseDefenseDelay minutes in [General] starts. It is stored on the attacker rather than on the defending house, so one satisfied call-up stops every house on the map from answering that same attacker until it expires.

A call-up that ran out of candidates before covering the budget sets no cooldown and runs again on the attacker’s next hit. A call-up canceled by defenders already fighting the attacker sets it only when their combined ratings pushed the budget below zero. One canceled to exactly zero — the single defender in the strength budget above — sets nothing, and neither does an attacker whose own rating is zero.

Campaign and skirmish differences

Five of the decisions above are settled differently by game type, and they are gathered here so that a page written mostly in one voice does not have to be re-read for the other. The pattern to take away is that a campaign holds the response back — no first enemy is ever picked, an armed building keeps its own defenders instead of calling for help, and a mission that forbids recruitment is honored where the other game types ignore it — while alliance breaking is the one rule a campaign relaxes rather than tightens.

Behavior	Campaign	Skirmish and multiplayer
Picking a first enemy	Never happens	The nearest non-passive, undefeated house, once the countdown expires
An armed building answering its own attack	Refuses the call-up and defends itself alone	Calls for help like any other structure
A candidate whose mission sets `Recruitable=no`	Rejected	Accepted; the mission’s setting is not consulted
Which houses count as human	The house under player control	Every house flagged as human
Breaking an alliance	Always proceeds	Requires that neither country is `MultiplayPassive=yes`

Settings and state without effect

Whiner=yes on a TeamType is read into a flag whose only test can never be reached. The damage routine sends a team member’s damage to its team and everything else down a second branch; the flag is tested on that second branch, behind a condition that only an object with no team can satisfy, so nothing that carries a team ever reaches it. A team that is hit before it began to move regroups instead, and one that is hit while moving turns on its attacker.

A house also carries a flag for having been alerted to an enemy, set for every computer house that builds a base or whose IQ reaches the production level, and set again by the Autocreate Begins… trigger action. The team-creation block that would have read it is disabled, and the live pass that replaced it ignores the parameter it is handed, so there is no alerted-team behavior; AutocreateTime reaches the same disabled block.

Two pieces of state are written and never read. Alongside the frame stamp that drives the attacked state, a damaged structure records which house the attacker belongs to, and nothing consults that record. The engine also declares a further house state for an enemy closing in on the base, which nothing ever assigns and nothing ever tests.

Filter keysRuntime effect

17 of 17

Key	Description	Value	When omitted
`AIHateDelays`global rules	The frames a computer house waits before picking its first enemy, one entry per difficulty.	list of integers	`(empty)`
`Armor`No effect in some scopes14 applicable types	An object type's armor class, or on a country or difficulty setting the divisor of the damage its objects take.	ArmorType	Varies by type
`AvoidThreats`TeamType	Fixes every member's threat avoidance at `1` while it is on the team.	boolean	`no`
`BaseDefenseDelay`global rules	Minutes an attacker is ignored after it has already drawn a full base defense response.	floating point	`.25`
`ComputerBaseDefenseResponse`global rules	Multiplies an attacker's ThreatPosed to size the defenders a computer house calls up.	integer	`3`
`Cost`6 applicable types	The credit price of one object of this type, or the multiplier a country or a difficulty applies to every price it pays.	integer	Varies by type
`IsBaseDefense`BuildingType, TeamType	Gives a BuildingType the computed ratings the computer picks base defenses by, or counts a TeamType against its house's defensive team total.	boolean	`no`
`MovementZone`AircraftType, BuildingType, InfantryType, UnitType	The terrain connectivity class the type's route and reachability tests are answered in.	mzonetype	`Normal`
`Priority`TeamType, Sounds	How firmly a team holds its members against other teams, or how hard a sound competes for a playback channel.	integer	Varies by type
`Recruitable`mission behavior	Whether an object in this mission may be taken onto a team.	boolean	`yes`
`Strength`No effect in some scopes12 applicable types	The maximum strength of most object types; wall overlays use it as a per-hit damage threshold.	integer	Partially documented
`SuspendDelay`global rules	Minutes a team stays suspended after a base attack emptied it.	floating point	`2`
`SuspendPriority`global rules	The TeamType priority a team must reach to survive a base attack.	integer	`20`
`ThreatAvoidanceCoefficient`AircraftType, BuildingType, InfantryType, UnitType	How heavily the type weighs the region threat figures when the pathfinder prices a route.	floating point	`0`
`ThreatPosed`AircraftType, BuildingType, InfantryType, UnitType	How much danger the type represents, used by team weighting, the region threat map, and base-defense call-ups.	integer	`0`
`ToProtect`AircraftType, BuildingType, InfantryType, UnitType	Whether damage to the object makes its computer house call defenders back to it.	boolean	`no`
`Verses`WarheadType	The percentage of a weapon's damage the warhead delivers against each armor class, in armor order.	string	`100%,100%,100%,100%,100%`