06 — Tech modifiers: ImprovedBy and AffectedBy

Index · Basics

Tech modifiers change a property of a unit type, missile, radar or explosion at run time, depending on technologies, unit tags, auras, lasting explosion effects or terrain. They are the main balancing tool: almost every upgrade in the shipped game is a tech modifier.

// (tech names below are illustrative)
ImprovedBy "Air_refuel" Range 1.5                                   // own tech: ×1.5
ImprovedBy "Powerful_Engine" Set Speed 65                            // own tech: = 65
ImprovedBy Unit "Advanced_Sonar" Add Range 100                      // own tech + unit has that tag: +100
AffectedBy Unit "Bomber_Stealth_Bonus_Modifier_1" Range 0.55        // target has that tag: ×0.55 (shipped)
AffectedBy InRange "EW" Sub Min 100 Range 500 Unless InRange "ACTIVE_EW_DEFENCE"

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1. General form

ImprovedBy | AffectedBy   [Unit | InRange | Terrain | Explosion]  "name"   [AND <condition>]…
    <body>                                    — or —      { <body> <body> … }

<body> :=   [Modify Weapon "missile"]  <operator>  <Property> ["tag"]  <value | value | Complex …>  [Unless <condition>]
         |  Movie …                    (appearance, see §6)
         |  Config "name" <Weapon lines>      (units only, see §6)
         |  Radar "radar" …                  (units only, see §6)

• A header decides when the modifier is active.
• AND <condition> adds extra conditions (up to 32) that must also hold.
• { … } lets one header carry several bodies (each body may have its own Unless):

ImprovedBy "Generation_4_Aircraft" { Set Size 0.03 Set Speed 1000 Set Range 3750 }

2. Headers

"Self" = the unit that owns the object being modified (for a missile: the launching unit; for a radar: the unit carrying it). "Target" = the other unit involved (the unit hit, the unit being looked at).

Header	Active when	Typical use
ImprovedBy "tech"	Self's faction knows tech.	Research upgrades.
ImprovedBy Unit "tag"	Self's faction knows tag and self's unit type has Modifier "tag".	Unit-specific upgrades; per-unit values via value.
ImprovedBy InRange "missile"	Self is inside the range of an active missile weapon of an own or allied unit.	Buff auras (research, espionage, force fields).
ImprovedBy Terrain "group"	Self (a ground unit) stands on terrain of that group (from the map's TerrainTypeMap).	Terrain bonuses.
AffectedBy "tech"	The target's faction knows tech.	Enemy counter-research (e.g. target's armour tech reduces your damage).
AffectedBy Unit "tag"	The target's faction knows tag and the target's unit type has Modifier "tag".	Stealth, hardening, special vulnerabilities.
AffectedBy InRange "missile"	Self is inside the range of an active missile weapon of an enemy unit.	Jamming, debuff auras.
AffectedBy Explosion "explosion"	Self was hit by that explosion and its LastingEffect is still running.	EMP, chemical, cyber effects.
AffectedBy Terrain "group"	The target (a ground unit) stands on that terrain group.	Cover/terrain protection.

Notes:

• InRange works only for weapons that are switched on, and for at most 32 different aura weapons per unit type. The aura's reach is the weapon's Range.
• For cities (VirtualCity), "self" is the city.
• Explosion modifiers written in an explosion entry use the attacker as self and the unit hit as target.

3. Operators

Operator	Written	Result
Multiply (default)	Range 1.5 or Multiply Range 1.5	value × 1.5
Set	Set Range 850	value = 850
Set Max	Set Max Range 850	value = max(value, 850)
Set Min	Set Min Range 850	value = min(value, 850)
Add	Add Range 100	value + 100
Sub	Sub Range 100	value − 100
Clamped variants	Add\|Sub\|Multiply Min <a> [Max <b>] \| Max <b> then property and value	apply, then clamp to ≥ a and/or ≤ b. Example: Sub Min 100 Range 500 = subtract 500 but not below 100.
Complex	Complex Range followed by case/default lines	choose an operation by condition (§5)
Delete	Delete Modifier "tag"	removes a unit tag (only with Modifier)

value instead of a number (only in Unit headers or case Unit): uses the tag's value from the unit's Modifier "tag" value <v> line.

4. Property names

The same keyword can mean different things on different objects (they share one stored value). Only use the names listed for the object you are modifying — a name from another column is accepted silently but changes a different property.

Keyword	Unit type	City (VirtualCity)	Missile	Radar	Explosion	Modify Weapon
Range	flight range	—	attack range	detection range	—	—
MinRange	= Size ⚠	= Size ⚠	min range	(no effect)	—	—
Size	size	city size	= MinRange ⚠	—	—	—
Precision	= MaxNumberOnMap ⚠	= MaxNumberOnMap ⚠	precision	(no effect)	—	—
MaxNumberOnMap	max on map	max on map	= Precision ⚠	—	—	—
Damage	= VirtualSpeed ⚠	—	explosion damage	—	—	—
VirtualSpeed	virtual speed	—	= Damage ⚠	—	—	—
Speed	speed ¹	—	speed ¹	—	—	—
TurnSpeed	turn speed	—	turn speed	—	—	—
CanBeIntercepted	= RepairRange ⚠	= RepairRange ⚠	interception chance	—	—	= Load ⚠
RepairRange	repair range	repair range	= CanBeIntercepted ⚠	—	—	= Load ⚠
ProductionCost	cost	—	cost	—	—	—
MaxElevation / Elevation / MaxHeight	max altitude	—	max altitude	max height	—	—
MinElevation	min altitude	—	min altitude	—	—	—
Power	hit points	city power	missile hit points	—	—	—
DisassembleTime	disassemble time	—	= LeadGuidance ⚠	—	—	—
LeadGuidance	= DisassembleTime ⚠	—	lead guidance	—	—	—
Heads / Launch / Production / AttackDelay / LastingEffect	AttackDelay	Production	Heads	—	LastingEffect	Launch
FakeHeads / Time / Science / AttackOnMove / LastingDamage	AttackOnMove	Science	FakeHeads	—	LastingDamage	Time
ResupplyRange / FullEffectRange / MinHealthPercentage	ResupplyRange	ResupplyRange	FullEffectRange	—	MinHealthPercentage	—
AffectedRange / Espionage / ModelLaunchTime	ModelLaunchTime	Espionage	AffectedRange (outer blast radius)	—	—	—
Load	—	—	—	—	—	(no effect)
CanBeBuilt	can be built (0/1)	—	can be built	—	—	—
Movie	appearance (§6)	—	appearance (§6)	—	—	—
Modifier	unit tags (§7)	city tags	—	—	—	—

In the rows with several keywords, every keyword of the row is interchangeable; the bold word is what it actually changes on that object. For readability write the matching word (Production on a city, AttackDelay on a unit, Heads on a missile).

¹ Do not change Speed with dynamic headers (InRange, Explosion, Terrain, AffectedBy); movement code caches it. Use simple ImprovedBy / ImprovedBy Unit only.

Modify Weapon

On a unit: ImprovedBy "tech" Modify Weapon "missile" <op> Launch|Time <value> changes that weapon in all of the unit's configs — salvo size or reload time (Load is accepted but currently has no effect). With Set/Add/Sub the Time value is in reload units like the Weapon line; with Multiply it is a factor. Modify Weapon cannot be used inside a weapon-config upgrade.

5. Complex modifiers

AffectedBy InRange "EW" Complex Range
  case InRange "ACTIVE_EW_DEFENCE" Multiply 1.0
  case "Anti-Jammers_Mk3"          Multiply 0.95
  case "Anti-Jammers_Mk2"          Multiply 0.85
  default                          Multiply 0.75

• When the header is active, the case lines are tested in order and the first true one is applied; default always matches — put it last.
• Each case has its own operator (including clamped variants) and value (or value for case Unit).
• Case conditions (same syntax as Unless and AND):

Condition	True when
"tech"	the checked faction knows tech
Unit "tag"	the checked faction knows tag and the checked unit type has that tag
InRange "missile" (optionally InRange Allied\|Own "missile")	the checked unit is inside an own/allied active missile aura
InRange Enemy "missile"	inside an enemy active missile aura
Explosion "explosion"	the checked unit is under that explosion's lasting effect
Terrain "group"	the checked unit stands on that terrain group
NOT <condition>	inverts it

Up to 32 cases.

6. Unless and AND

• Unless <condition> at the end of a body: the body is not applied if the condition is true ("this tech counters that effect"). One Unless per body.

AffectedBy "Satellite_Stealth_Bonus_Modifier_1" Range 0.7 Unless "Space_radar_Mk4" * AND <condition> right after the header name: all conditions must be true for the header to be active.

ImprovedBy Unit "Naval_Sonar" AND InRange "Sonar_Buoy" Range 1.3 // illustrative names

6.1 self and target in conditions

Write self or target right after case, Unless, AND (after an optional NOT) to choose whose faction/unit is checked:

Header type	Checked by default	To check the other side write
All ImprovedBy …, and AffectedBy InRange / AffectedBy Explosion	self	target
AffectedBy "tech", AffectedBy Unit, AffectedBy Terrain	target	self

Example — reduce damage against hardened targets unless the attacker has better guidance:

AffectedBy Unit "BM_Accuracy_Damage_Penalty" Complex Damage
  case self "Advanced_Inertial_Guidance" Multiply 1
  case self "Improved_Inertial_Guidance" Multiply 0.75
  default Multiply 0.5

7. Special bodies (units and missiles)

Appearance: Movie

Simple ImprovedBy "tech" only, no operator:

Form	Effect
ImprovedBy "tech" Movie Image "icon.png"	Replace only the icon (missiles, units).
ImprovedBy "tech" Movie "sprite.midx" [Icon "icon.png"] [RoundIcon "round.png"]	Replace the map sprite, optionally the icons (icon defaults to frame IconIDX of the sprite, round icon to the icon).
ImprovedBy "tech" Movie Model "model.midx"	Replace the 3D model. Can be combined with the previous form in the same { } block.
★ (sizes)	An upgrade's picture or model that is drawn bigger or smaller in its frame than the unit's first one gets a Scale in its own .midx (12); the upgrade itself has no size (a DrawSize here was read before, it is not any more).

delete ImprovedBy ALL Movie removes all appearance modifiers (handy in MODIFY entries before adding new ones).

Weapon configs and radar sets (units only)

Simple ImprovedBy "tech" only:

• ImprovedBy "tech" Config "name" + Weapon … lines — adds or replaces a config when tech is known. Written right after a config's own weapon list, ImprovedBy "tech" + Weapon lines replaces that config's contents (01 §3.3).
• ImprovedBy "tech" Radar "radar" [Radar …] — replaces the whole radar list when tech is known (01 §4).

8. Modifier tags

With the property Modifier "tag" a tech modifier adds, changes or removes a tag on the unit (or city) at run time; other objects then react to the tag through AffectedBy Unit "tag"/ImprovedBy Unit "tag".

[UNIT] "VirtualCity" MODIFY
  ImprovedBy InRange "FORCE_FIELD" Set Modifier "INVINCIBLE" 1.0     // cities under the field get the tag

[MISSILE] "Low-power nuclear bomb" MODIFY
  AffectedBy Unit "INVINCIBLE" Set Damage 0                            // …and take no damage

[UNIT] "Stealth_Bomber" MODIFY                                         // illustrative unit
  AffectedBy InRange "EW" Delete Modifier "Bomber_Stealth_Bonus_Modifier_1"          // loses stealth inside enemy EW

Tag changes are evaluated only for these headers: simple ImprovedBy "tech", ImprovedBy InRange, AffectedBy InRange, AffectedBy Explosion. (ImprovedBy Unit, simple AffectedBy, AffectedBy Unit and Terrain headers do not change tags.) A tag set to value 0 still exists — use Delete to remove it.

9. Evaluation order

For each property the base value is modified in this order; within each group, in the order the lines appear (across MODIFY entries, appended lines come last):

1. simple ImprovedBy "tech"
2. ImprovedBy Unit
3. ImprovedBy Terrain
4. ImprovedBy InRange
5. AffectedBy InRange
6. AffectedBy Explosion
7. simple AffectedBy "tech"
8. AffectedBy Unit
9. AffectedBy Terrain

Because operations are applied in sequence, Set discards everything before it and multiplications compound: ImprovedBy "A" Range 1.2 + ImprovedBy "B" Range 1.2 = ×1.44. To make an upgrade chain where the last known level wins, use Set in increasing order (the shipped data does this: Set Range 850, then Set Range 1000).

Steps 1–2 (and a Complex whose cases only test techs) are cached per faction and cheap. Steps 3–9 and any value, InRange, Explosion or Terrain condition are evaluated per unit and cost CPU on large maps.

10. Deleting modifiers

Form	Removes
delete ImprovedBy "tech"	All simple ImprovedBy lines with that tech, for every property.
delete ImprovedBy Unit "tag"	All ImprovedBy Unit "tag" lines.
delete ImprovedBy InRange "missile"	All ImprovedBy InRange "missile" lines.
delete ImprovedBy ALL <Property>	All simple ImprovedBy lines for that property (… Unit ALL <Property>, … InRange ALL <Property> likewise).
delete AffectedBy …	Same forms, plus Explosion "explosion".
reset AffectedBy	Every AffectedBy of the object.
reset ImprovedBy	Every ImprovedBy of the object.