Units-UnitDefs

Location

UnitDef files are .lua files stored in the Units/ directory of a Spring Game.

Purpose

UnitDef files have one purpose; to define the properties of units. They are the main description file for what attributes your unit should have and how it should behave.

Source

The engine source code which loads the tags from these files is viewable here:

rts/Sim/Units/UnitDef.cpp

The engine source which reads the #sounds subtable can be found here:

rts/Sim/Units/UnitDefHandler.cpp

Data Types

Tags may be one of the following data types:

int - An integer number
float - A number with decimals.
bool - A value which can be true or false.
string - Text, or more precisely a string of alphanumeric characters.
float[3] - A vector, with three float components, representing x, y and z axes (y is 'up').

Details

There follows a comprehensive (certain deprecated tags are not present) list of the tags available, their data type, default value and a brief description of what they do. Bear in mind that the source code linked above is the ultimate reference when dealing with these tags.

In lua tables keys (i.e. the tags) should be lower case, here they are represented in camelCase for readability. In your files you may use the lowerkeys function on your final table to ensure the keys are properly cased.

It is usual to name the returned UnitDef table the internal unitName desired for the unit.

General

string name Default: "" lua: humanName: This is simply the name of the unit as it appears to the player.

string description Default: name lua: tooltip: This is the tooltip description of the unit seen by the player. It defaults to the name = of the unit.

string buildPic Default: "" lua: buildPicName: The filename of the image to be used as the build picture, assumes Unitpics/ directory (see Units:Buildpics).

string objectName Default: "" lua: modelName: The filename of the 3D model file for this unit, assumes Objects3D/ directory.

string script Default: unitName + ".cob" lua: scriptName: The filename of the animation script file for this unit, assumes Scripts/ directory. Default assumes .cob file but LUS should be preferred.

float maxDamage Default: 0.0 lua: health: The base 'hitpoints' the unit will have.

float autoHeal Default: 0.0: How much health the unit will regain every second.

float idleAutoHeal Default: 10.0: How much health the unit will regain every second whilst it is idle.

int idleTime Default: 600: The time in frames taken until a unit is considered to be idle.

float buildCostMetal Default: 1.0 lua: metalCost: The amount of metal resource the unit costs to build. Cannot be below 1.0.

float buildCostEnergy Default: 0.0 lua: energyCost: The amount of energy resource the unit costs to build.

float buildTime Default: 0.0: The time taken to build the unit, in conjunction with the workerTime = of the constructor. Effectively, Time to build = buildTime / workerTime. Defaults to 0.0 but cannot actually be below 1.0.

float mass Default: buildCostMetal: The mass of the unit, used in weapon impulse calculations. Cannot be less than 1.0.

bool reclaimable Default: true: Can the unit be reclaimed by a builder?

bool capturable Default: true: Can a unit be stolen by a builder using the capture command?

bool repairable Default: true: Can the unit be repaired by a builder?

float maxRepairSpeed Default: 1e20: The maximum cumulative speed at which this unit can be repaired.

string iconType Default: "default": The name of the radar icon type this unit should use (see Icontypes.lua).

string corpse Default: "": The name of the feature this unit should leave behind as a wreck when it dies (see Units-FeatureDefs).

string explodeAs Default: "": The name of the weapon this unit should explode as when it is killed (see Units-WeaponDefs).

string selfDestructAs Default: "": The name of the weapon this unit should explode as when it self destructs (see Units-WeaponDefs). Also used as the kamikaze = weapon.

Resources

float metalStorage Default: 0.0: The amount of the metal resource storage the unit contributes.

float energyStorage Default: 0.0: The amount of the energy resource storage the unit contributes.

float extractsMetal Default: 0.0: The amount of the metal resource the unit extracts from the ground. The amount extracted depends on the metal map defined in the map itself. Works only for structures.

float windGenerator Default: 0.0: The amount of the energy resource the unit generates which is dependant on the map wind. Works only for structures.

float tidalGenerator Default: 0.0: The amount of the energy resource the unit generates which is dependant on the maps tidal power. Clearly, this only works on water structures.

float metalUse Default: 0.0 lua: metalUpkeep: The amount of the metal resource the unit consumes per game 'tick'.

float energyUse Default: 0.0 lua: energyUpkeep: The amount of the energy resource the unit consumes per game 'tick'.

float metalMake Default: 0.0: The amount of the metal resource the unit generates unconditionally per game 'tick'.

float energyMake Default: 0.0: The amount of the energy resource the unit generates unconditionally per game 'tick'.

float makesMetal Default: 0.0: The amount of the energy resource the unit turns into the metal resource per game 'tick'.

Sensors

bool onoffable Default: false: Does the unit have an on/off button? Currently the activation status tied to this button also turns sensors (other than LOS) on and off.

bool activateWhenBuilt Default: false: Should the unit's activation status be on or off when it is created?

float sightDistance Default: 0.0 lua: losRadius: The radius of the units sight (LOS is circular in Spring)

float airSightDistance Default: 1.5 * sightDistance lua: airLosRadius: How far away the unit can see aircraft (and some FX).

float losEmitHeight Default: 20.0 lua: losHeight New in version 83.0: How high up the unit is the point used to calculate it's LOS vs. the terrain?

float radarEmitHeight Default: 20.0 lua: radarHeightNew in version 83.0: How high up the unit is the point used to calculate it's radar vs. the terrain?

int radarDistance Default: 0 lua: radarRadius: The radius of the units radar.

int sonarDistance Default: 0 lua: sonarRadius: The radius of the units sonar.

int radarDistanceJam Default: 0 lua: jammerRadius: The radius of the units radar jamming.

int sonarDistance Default: 0 lua: sonarJamRadius: The radius of the units sonar jamming.

bool stealth Default: false: Is the unit undetectable by radar?

bool sonarStealth Default: false: Is the unit undetectable by sonar?

int seismicDistance Default: 0 lua: seismicRadius: The radius of the unit's seismic (movement) sensor.

float seismicSignature Default: 0 for units with floater = , canHover = or canFly = , otherwise sqrt(mass / 100.0): How fast the seismic ring expands in elmos per frame. Each ping always lasts 15 frames, so this also determines the maximum radius of the seismic ring.

Cloaking

For units with canCloak = true:

float cloakCost Default: 0.0: The energy cost per tick to cloak the unit while it is stationary.

float cloakCostMoving Default: cloakCost: The energy cost per tick to cloak the unit while it is moving.

bool initCloaked Default: false lua: startCloaked: Is the unit cloaked as soon as it is created?

float minCloakDistance Default: 0.0: The minimum distance (radius) which the unit must be from any enemy units to remain cloaked.

bool decloakSpherical Default: true: Does minCloakDistance = apply in 3D or only 2D? i.e. can aircraft flying above the unit decloak it?

bool decloakOnFire Default: true: Does the unit decloak when it fires a weapon?

int cloakTimeout Default: 128: The minimum time, in frames, between a decloak and subsequent re-cloak.

Commands

bool canMove Default: false: Can the unit be issued Move orders?

bool canAttack Default: true: Can the unit be issued Attack orders?

bool canFight Default: true: Can the unit be issued Fight orders?

bool canPatrol Default: true: Can the unit be issued Patrol orders?

bool canGuard Default: true: Can the unit be issued Guard orders?

bool canCloak Default: false: Can the unit be issued Cloak orders?

bool canRepeat Default: true: Can the unit be issued Repeat orders?

bool canSelfDestruct Default: true lua: canSelfD: Can the unit be issued a self destruct order?

int moveState Default: -1 for mobile units, 1 for structures: The initial movement state for the unit. Can be -1 - Inherits from factory, 0 - Hold Position, 1 - Manoeuvre or 2 - Roam.

int fireState Default: -1 for units with noAutoFire = false, 2 otherwise: The initial firing state for the unit. Can be -1 - Inherits from factory, 0 - Hold Fire, 1 - Return Fire or 2 - Fire At Will.

bool noAutoFire Default: false lua: canFireControl: Controls whether or not the unit has a fire state button.

bool canManualFire Default: false: description = Can the unit be issued ManualFire commands? A ManualFire command will fire any weapons with the commandfire = tag.

Builder Commands

bool canRestore Default: builder && terraformSpeed = > 0: Can the unit be issued restore terrain commands? For builders only.

bool canRepair Default: builder && repairSpeed = > 0: Can the unit be issued repair commands? For builders only.

bool canReclaim Default: builder && reclaimSpeed = > 0: Can the unit be issued reclaim commands? For builders only.

bool canResurrect Default: builder && resurrectSpeed = > 0: Can the unit be issued resurrection commands? For builders only.

bool canCapture Default: builder && captureSpeed = > 0: Can the unit be issued capture commands? For builders only.

Builder

bool builder Default: false: Is the unit a builder?

float buildDistance Default: 128.0: How far away from itself the unit can build, measured to the centre of the unit being built. The minimum value is 38.0.

bool buildRange3D Default: false: Does the builders buildDistance = apply in all 3 dimensions or only 2?

float workerTime Default: 0.0 lua: buildSpeed: How fast the builder builds, used in conjunction with the buildTime = of the unit being built. Effectively, Time to build = buildTime / workerTime. If this value is <= 0.0 then builder = is set to false.

float repairSpeed Default: workerTime: How fast the builder can repair other units.

float reclaimSpeed Default: workerTime: How fast the builder can reclaim other units and features.

float resurrectSpeed Default: workerTime: How fast the builder can resurrect corpse features back into living units.

float captureSpeed Default: workerTime: How fast the builder can capture other units.

float terraformSpeed Default: workerTime: How fast the builder levels and restores terrain.

bool canAssist Default: builder: Can the builder assist other constructions?

bool canBeAssisted Default: true: Can the builder be assisted by other builders?

bool canSelfRepair Default: false: Can the builder repair itself?

bool showNanoSpray Default: true: Does the builder emit OTA-style nanospray whilst constructing?

float[3] nanoColor Default: {0.2, 0.7, 0.2} aka green: The RGB colour of a builders' emitted nano particles if showNanoSpray = true. Also controls the RBG colour of a unit's own nanoframe if showNanoFrame = true.

bool fullHealthFactory Default: ?: If true, units are repaired before they are allowed to leave the factory i.e. units from this factory will be healed back to 100% health if they are damaged during construction.

bool isAirbase Default: false: Is this unit an airbase? Aircraft may land and repair on units which are airbases.

Movement & Placement

int footprintX Default: 1: How wide the unit is in footprint units, left to right. 1 footprint unit = 16 elmos. Cannot be below 1. For mobile units this should be the same as the footprintX = of its movementClass = . Also used for obstacle avoidance.

int footprintZ Default: 1: How wide the unit is in footprint units, top to bottom. 1 footprint unit = 16 elmos. Cannot be below 1. For mobile units this should be the same as the footprintZ = of its movementClass = . Also used for obstacle avoidance.

string yardmap Default: ""

Used to determine a structure from a mobile unit. A string of characters which defines in detail each 'footprint square' of the structure. Each footprint square may be:

y - 'Yard' - Always open, unblocking,

c - 'Construction' - Open and unblocking only while constructing (for factories, controlled via COB.YARD_OPEN see Animation-LuaCallouts#Other),

i - 'Inversed Construction' - Closed and blocking only while constructing (for factories, controlled via COB.YARD_OPEN see Animation-LuaCallouts#Other) (New in version 89.0),

g - 'Geothermal' - Flags that the unit must be placed over a geoThermal feature, does not actually count as a square,

h - 'High Resolution' - Indicates that the yardmap will use double resolution with four times as many characters. Must be the first character, and does not count as a square itself (New in version 93.0),

o - 'Obstacle' - Always closed, blocking, all other chars are treated the same way.

Tip: 'Draw' out the yardmap over multiple lines. As of 89.0 all whitespace characters are ignored, including newlines.

bool levelGround Default: false: For structures. Does the constructor have to level the ground underneath the build area before beginning to build the structure?

string movementClass Default: "": The name of the movement type a mobile, non aircraft, unit should use. See Movedefs.lua. Other tag usage should be consistent with this i.e. canHover = true IFF using a HOVER based movetype.

bool canHover Default: false: Is the unit a hovercraft? Hovercraft can cross water of any depth without a speed penalty. Hover's must also have HOVER within the name of their movementClass = (see Movedefs.lua).

bool floater Default: true if waterline = true, false otherwise: When a mobile unit is crossing water, or a structure is placed on water, does it float on top of the water or crawl / lay on the sea bed?

bool upright Default: false: Does the unit follow the terrain or always remain upright? Generally used for walkers.

float maxSlope Default: 0.0 lua: maxHeightDif (value changed): The maximum slope a building can be placed on. Mobile unit's use the maxSlope = set in their movementClass = . The value is in degrees and is clamped between 0.0 and 89.0. This value is converted to a "maximum allowed height difference" (call it M), which involves a hard-coded constant. When a building gets placed, the height of each of its footprint squares is compared to a reference height (calculated for the build position). If the difference exceeds M for any square, that build position is rejected.

float minWaterDepth Default: -10e6: The minimum depth of water a building can be placed on. Mobile unit's use the minWaterDepth = set in their movementClass = .

float maxWaterDepth Default: 10e6: The maximum depth of water a building can be placed on. Mobile unit's use the maxWaterDepth = set in their movementClass = .

float waterline Default: 0.0: How low in the water does a ship sit? Higher values means the ship is lower in the water.

float minCollisionSpeed Default: 1.0: The minimum net impact speed that will cause a unit to be damaged by collisions with another unit.

bool pushResistant Default: false: Can the unit be pushed around by other units? Turning it on doesn't remove all pushing but is a marked improvement.

float maxVelocity Default: 0.0 lua: ud.speed: The maximum speed attainable by the unit in elmos per frame. If the value is -ve, the absolute value is used.

float maxReverseVelocity Default: 0.0 lua: missing: The maximum speed attainable by the unit in reverse in elmos per frame. If the value is -ve, the absolute value is used.

float acceleration Default: 0.5 lua: maxAcc: The acceleration of the unit, in elmos per frame². If the value is -ve, the absolute value is used.

float brakeRate Default: 3.0 * acceleration lua: maxDec: The deceleration of the unit, in elmos per frame². If the value is -ve, the absolute value is used. For units with canFly = true this is multiplied by 0.1.

float turnRate Default: 0.0: How fast the unit can turn. degrees per seconds = 0.16 * turnRate.

bool turnInPlace Default: true: Does the unit turn on the spot (like a person or tank) or must it be moving forwards to turn (like a car).

float turnInPlaceSpeedLimit Default: A complex formula based on turnRate = and maxVelocity =: For units with turnInPlace = false, this defines the minimum speed it will slow down to (the speed at which the turn is actually performed can be higher depending on the angular difference and turnRate = ).

float turnInPlaceAngleLimit Default: 0.0 New in version 86.0: For units with turnInPlace = true, defines the maximum angle (in degrees) of a turn above which it starts to brake.

bool blocking Default: true: Does the unit block the movement of other units? (Mines, i.e. non-mobile units with the kamikaze = tag default to false).

float crushResistance Default: mass New in version 85.0: How resistant is the unit to being crushed? Any MoveClass with a crushStrength = greater than this will crush the unit - IFF this has been enabled via Spring.SetUnitBlocking and the collider impulse exceeds that of the colidee.

Flanking

For a deeper explanation of these tags, see Units:FlankingBonus.

int flankingBonusMode Default: flankingBonus.defaultMode set in Modrules.lua: The mode of operation of Spring's inbuilt flanking system. Can be 0 - No flanking bonus. Mode 1 builds up the ability to move over time, and swings to face attacks, but does not respect the way the unit is facing. Mode 2 also can swing, but moves with the unit as it turns. Mode 3 stays with the unit as it turns and otherwise doesn't move, the ideal mode to simulate something such as tank armour.

float[3] flankingBonusDir Default: {0.0, 0.0, 1.0}: This is the direction vector where the armour is facing; i.e. where the least damage is applied. The default is straight forwards.

float flankingBonusMax Default: 1.9: The maximum multiplier to the damage dealt, when a unit is hit from the opposite direction to flankingBonusDir = .

float flankingBonusMin Default: 0.9: The minimum multiplier to the damage dealt, when a unit is hit from the same direction as flankingBonusDir = .

float flankingBonusMobilityAdd Default: 0.01: This defines the ability of flankingBonusDir = to move over time. Its value is added to the mobility every SlowUpdate. When the unit is attacked, the build up mobility value is multiplied by a vector facing the attack, which is added to flankingBonusDir = .

Aircraft

bool canFly Default: false: Can the unit fly, i.e. is it an aircraft?

bool canSubmerge Default: false: Can the aircraft land underwater?

bool factoryHeadingTakeoff Default: true: Controls the take-off behaviour of aircraft with hoverAttack = true. true means planes start matching their heading right after taking off from the pad, false means they maintain the heading of the pad until reaching cruiseAlt = .

bool collide Default: true: Does the unit collide with other aircraft, or can it occupy the same space?

bool hoverAttack Default: false: Controls whether the aircraft flys and attacks like a fighter/bomber or a helicopter/gunship.

bool airStrafe Default: true: For aircraft with hoverAttack = true, controls if the unit strafes side to side while attacking or remains stationary.

float cruiseAlt Default: 0.0 lua: wantedHeight: The altitude in elmos which the unit attempts to fly at while cruising.

float airHoverFactor Default: -1.0 lua: dlHoverFactor: For aircraft with hoverAttack = true, less then 0 means it can land and >= 0 indicates how much the unit will move during hovering on the spot.

bool bankingAllowed Default: true: For aircraft with hoverAttack = true, controls whether or not the unit banks when moving turning.

bool useSmoothMesh Default: true: Does the aircraft follow the real map terrain or the special smoothed out navigation mesh generated by Spring specifically for aircraft?} Can become problematic for construction aircrafts, building in canyons.

float maxFuel Default: 0.0: The maximum flight time in seconds before aircraft must return to an airbase to refuel.

float refuelTime Default: 5.0: The time in seconds required to refuel the aircraft at an airbase.

float minAirbasePower Default: 0.0: The minimum workerTime = an airbase must have to repair / refuel this aircraft.

bool canLoopbackAttack Default: false: Can the aircraft perform an Immelmann turn?

Advanced Air Tags

The following set of tags are not well understood and using non-default values can lead to undesired flight behaviours.

float wingDrag Default: 0.07: The drag caused by the aircraft's wing. Clamped between 0.0 and 1.0.

float wingAngle Default: 0.08: The angle between the front and the wing plane.

float frontToSpeed Default: 0.1: Fudge factor for lining up speed and front of plane.

float speedToFront Default: 0.07: Fudge factor for lining up speed and front of plane.

float myGravity Default: 0.4: As Spring aircraft are slower than real aircraft this tag allows to lower gravity to compensate. Multiplies against map gravity.

float crashDrag Default: 0.005: The drag used when crashing. Clamped between 0.0 and 1.0.

float maxBank Default: 0.8: The maximum roll (z-axis rotation) the aircraft can achieve.

float maxPitch Default: 0.45: The maximum pitch (x-axis rotation) the aircraft tries to keep.

float turnRadius Default: 500.0: Hint to Spring unit AI about the required turning radius.

float verticalSpeed Default: 3.0: The speed of takeoff and landing, at least for gunships (hoverAttack = true).

float maxAileron Default: 0.015: The maximum turn speed around the roll (z) axis.

float maxElevator Default: 0.01: The maximum turn speed around the pitch (x) axis.

float maxRudder Default: 0.004: The maximum turn speed around the yaw (y) axis.

float maxAcc Default: 0.065: The maximum acceleration or 'engine power' of the aircraft.

Flares

The following set of tags are rarely used and are hardcoded to only work vs. missile weapons. The texture is hardcoded to be flareprojectiletexture defined in Resources.lua.

bool canDropFlare Default: false: Can this aircraft drop flares to distract missile weapons?

float flareReload Default: 5.0 lua: flareReloadTime: The time in seconds between successive flare drops.

float flareDelay Default: 0.3: The delay between detecting an incoming missile and launching flares. Multiplied by a random number between 1 and 16.

float flareEfficiency Default: 0.5: The probability that an incoming missile will target the flare instead of the aircraft.

float[3] flareDropVector Default: {0.0, 0.0, 0.0}: The direction vector which flares are emitted in.

int flareTime Default: 3: The lifetime of a dropped flare in frames.

int flareSalvoSize Default: 4: How many flares are dropped at once?

int flareSalvoDelay Default: 0: The delay in frames between the release of each individual flare in a burst.

Transports

int transportSize Default: 0: The size of units that the transport can pick up, in terms of the passengers footprintX = .

int minTransportSize Default: 0: The smallest size of unit that the transport can pick up, in terms of the passengers footprintX = .

int transportCapacity Default: 0: The total number of units that the transport can pick up, with each unit multiplied by it's footprintX = size. If this tag is not present, then any AttachUnit and DropUnit call in the animation script will be ignored (See Animation-LuaCallouts#Other)

float transportMass Default: 100000.0: The total cumulative mass = of passengers the transport can carry.

float minTransportMass Default: 0.0: The minimum mass = passenger the transport can carry.

float loadingRadius Default: 220.0: How far away in elmos can the transporter pick up and drop units?

float unloadSpread Default: 1.0: How spread out the passengers are when unloaded. Is multiplied by the passengers radius.

bool isFirePlatform Default: false: Can transported units still aim and shoot while loaded by this transport?

bool holdSteady Default: false: If true - passengers are slaved to orientation of transporter attachment piece, if false - passengers are slaved to orientation of transporter body.

type releaseHeldelmos bool Default: false: Does the transporter unload it's passengers when it dies?

bool cantBeTransported Default: false for mobile units, true for structures: Controls if a unit is transportable at all or not. If false it is overridden by Modrules.lua transportability subtable tags.

bool transportByEnemy Default: true: Controls if a unit can be transported by an enemy transport. i.e. can it be kidnapped.

int transportUnloadMethod Default: 0: For air transports. Can be 0 - Land to unload individually, 1 - Flyover drop (i.e. Parachute), or 2 - Land and flood unload all passengers. Can be used on ground transports with mixed results.

float fallSpeed Default: 0.2: For air transports with transportUnloadMethod = 1. The speed in elmos per second which units will fall at when released from the transport.

float unitFallSpeed Default: 0.0: Allows you to override fallSpeed = for an individual passenger.

Decals

bool leaveTracks Default: false: Does the unit leave a track mark decal behind it when it moves? For mobile units.

string trackType Default: "stdTank": The filename of the image, without extension, assumed to be in Bitmaps/Tracks/, to be used as the track decal. The red channel of the image controls the brightness and the green channel the alpha (how visible it is) of the track. Blue channel is unused.

float trackWidth Default: 32.0: The width of the track decal left on the ground, in elmos.

float trackOffset Default: 0.0: How far back in elmos the track should be drawn from the centre of the unit.

float trackStrength Default: 32.0: How visible or 'deep' the track mark should be. Also used to determine how long the decal should last.

float trackStretch Default: 1.0: How much the track is stretched in the forward direction compared to the sides (i.e. used to change aspect ratio).

bool useBuildingGroundDecal Default: false: For structures, do they display a ground decal on the terrain under their model?

string buildingGroundDecalType Default: "": The filename of the image to be used as ground decal. Assumed to be in Unittextures/.

int buildingGroundDecalSizeX Default: 4: How wide the decal is left to right, in footprint units.

int buildingGroundDecalSizeY Default: 4: How wide the decal is top to bottom, in footprint units.

float buildingGroundDecalDecaySpeed Default: 0.1: A measure of how quickly the decal should fade out if the structure dies. Essentially this value is multiplied by the time since death and subtracted from the original alpha until the decal is fully transparent.

Collision Volumes

For a deeper explanation of these tags, see Unit Collision Volumes.

float[3] modelCenterOffset Default: {0.0, 0.0, 0.0} Removed in 89.0 (Now set via lua): How far from the model's defined centre should the centre of the unit be?

bool usePieceCollisionVolumes Default: false: When turned on the model and UnitDef collision volumes are ignored and Spring generates a bounding box volume for each piece of the unit model. These volumes can be manipulated or replaced by Spring.SetUnitPieceCollisionVolumeData. Increases the performance cost of collision calculations.

string collisionVolumeType Default: "": What shape should the unit's collision volume be? Can be box, ellipsoid or a cylinder aligned to an axis; cylX, cylY, cylZ.

float[3] collisionVolumeScales Default: {0.0, 0.0, 0.0}: The lengths of the collision volume in each of the three axes. Note that non-spherical ellipsoids and elliptical cylinders are not supported.

float[3] collisionVolumeOffsets Default: {0.0, 0.0, 0.0}: The offset from the unit centre to the hit volume centre in each axis.

bool useFootPrintCollisionVolume Default: false New in version 92.0: Replaces any defined collision volume with a box with dimensions equal to the object's footprint (this also overrides any custom scaling and/or offsets).

int collisionVolumeTest Default: 0 Removed in 90.0 (Now always continuous): The type of test used to detect collisions. Can be 0 (discrete) or 1 (continuous). Use the latter for catching high speed projectiles which may otherwise 'skip through' small collision volumes, but beware of the increased performance cost.

Attack Behaviours

int highTrajectory Default: 0 lua: highTrajectoryType: Can the unit fire it's (ballistic) weapons in a high trajectory arc? Can be 0 - Low trajectory only, 1 - High trajectory only, or 2 - Toggle button.

bool kamikaze Default: false lua: canKamikaze: Does the unit attack its target by blowing itself up?

float kamikazeDistance Default: 0.0 lua: kamikazeDist: How close to the target, in elmos, the unit must get before detonating. Measured in 3D, not 2D.

bool kamikazeUseLOS Default: false: Does the target unit have to be in LOS when detonating or only within kamikazeDistance = .

bool strafeToAttack Default: false: Should the unit move sideways when it can't shoot?

Other

string decoyFor Default: "": The UnitDef name (not human name = ) which this unit is a decoy for.

int selfDestructCountdown Default: 5 lua: selfDCountdown: The length in seconds taken between issuing self destruct order and the unit exploding.

float damageModifier Default: 1.0 lua: armoredMultiple: The multiplier applied to weapon damage when the units ARMORED status (See Lua_ConstCOB) is turned on.

bool isTargetingUpgrade Default: false lua: targFac: Does the unit upgrade the targeting so that units shoot accurately at enemy units which are in radar but not in LOS.

bool isFeature Default: false: Does the unit immediately die into it's corpse = feature when built? Used mainly for making walls.

bool hideDamage Default: false: Should the units current health be invisible to enemy players?

bool showPlayerName Default: false: Should the unit display it's controlling player as its name instead of name = . Generally used for commander or hero units.

bool showNanoFrame Default: true: Does the unit show an OTA-style nanoframe whilst being constructed?

int unitRestricted Default: MAX_UNITS lua: maxThisUnit: How many of this unit type may a player control at once? Defaults to being the maximum amount of units controllable. Is overridden by lobby unit restrictions.

float power Default: buildCostMetal = + (buildCostEnergy = / 60.0): The relative power of the unit. Used in weapon targeting priority and experience gain calculations.

Sub Tables

weapons

The weapons subtable of a UnitDef tells Spring which weapons the unit has. It is a simple array (number indexed table) of weaponNames (not the human readable name!).

The following additional tags are associated with this subtable:

string name Default: "": The weaponName of the weapon (See Units-WeaponDefs). If using the weapondefs_post.lua provided by springcontent.sdz, you may include the WeaponDef tables within the UnitDef as the weaponDefs subtable, and refer to them with def rather than name. This can be a useful way to organise definitions if units do not generally share weapons.

string badTargetCategory Default: "": A string of unit category = entries which this weapon prefers to avoid targeting. i.e. given two units which can be targeted, any unit whose category = matches any entry in this tag, will be targeted last. (See #Categories)

string onlyTargetCategory Default: "": A string of unit category = entries which this weapon can target. i.e. any unit whose category = does not match any entry in this tag, cannot be targeted by this weapon. (See #Categories)

int slaveTo Default: 0: The number of the weapon which this weapon is slaved to. A slaved weapon can only target what it's master is targeting. Weapon numbers start at 1 and correspond to the index of the weapon within the subtable.

float[3] mainDir Default: {0.0, 0.0, 1.0} i.e. forwards: A vector representing the firing direction of this weapon if it has a limited firing arc. Used in conjunction with maxAngleDif = (See Units:WeaponMainDir).

float maxAngleDif Default: 180.0: How wide this weapons limited firing arc is in degrees. Symmetrical about mainDir = i.e. 180.0 is 90 degree freedom either way (See Units:WeaponMainDir).

float fuelUsage Default: 0.0: How much fuel in seconds is deducted from the units initial maxFuel = when this weapon fires.

buildOptions

The buildOptions subtable of a UnitDef tells Spring which other units the unit can build (in the case of a builder) or produce (in the case of a factory). It is a simple array (number indexed table) of unitNames (not the human readable name = !).

There are no additional tags specific to this subtable.

SFXTypes

The SFXTypes subtable of a UnitDef tells Spring which CEG effects are associated with the unit. It consists of two further subtables, with no additional tags specific to them.

explosionGenerators

The explosionGenerators subtable of SFXTypes tells Spring which CEGs the unit's script can call, via the EmitSFX() callout (See Animation-LuaCallouts#Effects). It is a simple array (number indexed table) of CEG names, prefaced by the string "custom:".

pieceExplosionGenerators

New in version 83.0

The pieceExplosionGenerators subtable of SFXTypes tells Spring which CEGs the unit's script can pick at random to attach to a flying unit piece, created from the Explode() callout (See Animation-LuaCallouts#Effects). It is a simple array (number indexed table) of CEG names, with no prefix.

Forum thread (with examples): pieceExplosionGenerators

sounds

The sounds subtable of a UnitDef tells Spring which sound files to play when the unit triggers various events.

Files are assumed to be in the Sounds/ directory; accepted formats are .wav and .ogg, the former being assumed if no extension is given.

Sounds can be defined in one of three ways:

Each event can be used as though it were a string tag referring to the filename.
Each event can be the name of a subtable, which is a simple array containing the filenames. One sound is picked at random from the list each time the event occurs.
Each event can be the name of a subtable, which is a simple array containing further tables, which contain the following tags:

string file Default: "": The filename of the sound to play.

float volume Default: 1.0: The default volume of the sound.

Spring checks any referenced sound filename to see if a SoundItem has been created, which allows greater control over how it is played (See Sounds.lua).

sounds Example

For clarification, here is an example of all three methods:

sounds = {
  -- Method 1
  ok = 'oksound', -- .wav appended
  -- Method 2
  arrived = {
    'arrived1.wav',
    'arrived2.wav',
  },
  -- Method 3
  select = {
    { file = 'selsound1.ogg', volume = 2.0 },
    { file = 'selsound2.ogg', volume = 2.5 },
  },
}

sounds Events

The events called by the engine are as follows:

ok

Unit is issued a command.

select

Unit is selected by the player.

arrived

Unit has arrived at its destination. Mobile ground units only.

build

Unit begins building. Called for both factories and mobile construction units.

activate

Unit is activated, i.e. Is turned on. Also called when a mobile ground unit starts moving.

deactivate

Unit deactivates, i.e. Is turned off.

cant

Unit cannot carry out this order. Loaded but not currently called by the engine.

underattack

Unit gets attacked. Loaded but not currently called by the engine.

customParams

The customParams subtable of a UnitDef allows the game designer to give their units custom attributes, which can then be accessed via lua gadgets and widgets. It is a map (key-value pair indexed table) of strings. When accessing these attributes in lua the strings can be turned back into numbers, bools or even tables. This gives great control to game designers to essentially implement their own behaviour tags.

There are no additional tags specific to this subtable

Examples

'Balanced Annihilation' UnitDefs

'Complete Annihilation' UnitDefs

'Conflict Terra' UnitDefs

'Evolution RTS' UnitDefs

'Spring Tutorial Game' UnitDefs

'ZeroK' UnitDefs

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