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Development < Gamedev:Main < Gamedev:WeaponDefs


WeaponDef files are .lua files stored in the Weapons/ directory of a Spring Game. Alternatively they can be integrated into UnitDefs.


WeaponDef files have one purpose; to define the properties of weapons. They are the main description file for what attributes your weapon should have and how it should behave. Since version 100.0, Spring will record a warning whenever it finds an unknown tag.


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

Data Types

An integer number. eg. 5
A number with decimals. eg 1.023
A value which can be true or false. eg true
Text, or more precisely a string of alphanumeric characters. eg "string of characters"
Three float components, representing red, green and blue components, ranged from 0.0 to 1.0. eg {0.0, 0.0, 0.0}
Three float components, eg {0.0, 0.0, 0.0}
Four float components, eg {0.0, 0.0, 0.0, 0.0}


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 WeaponDef table the internal weaponName desired for the weapon.


The following tags are common to all or at least a majority of WeaponTypes, depending on the tag.


string weaponType  default: "Cannon"

Spring has 14 WeaponTypes which provide game developers with basic behaviours which they can customise to an extent with the WeaponDef tags. Some tags are specific to certain WeaponTypes and not implemented for others, this two-way table indicates which tags work for which types. The possible values are:

string name  default: "Weapon"

The descriptive name of the weapon as listed in FPS mode.

bool turret  default: false

Does the unit aim within an arc (up-to and including full 360° turret traverse) or always aim along the owner's heading?

bool noSelfDamage  default: false

Can the weapon's explosion damage the unit which fires it? Useful for preventing bombers with high-yield weapons destroying themselves.

bool impactOnly  default: false

Does the weapon only deal damage through direct hits and not 'splash' damage through areaOfEffect?

bool noExplode  default: false

Does the weapon explode on impact with a target or continue through? Note that these weapons will do damage every single frame they are inside the collision volume of an object, underground or under water, massively multiplying their damage.

bool burnblow  default: false lua: selfExplode

Does the weapon explode when it reaches its maximum range or continue on its path? The name is an OTAism.

float range  default: 10.0

The maximum range in elmos that the weapon can fire at.

float weaponVelocity  default: 0.0

The velocity in elmos per second of the weapon projectile. Since 99.0 maxVelocity is a synonym.

float reloadTime  default: 1.0

The time in seconds between shots fired.

float metalPerShot  default: 0.0

Metal used per shot. If the specified amount is not available, the weapon cannot be fired. Can also be used to specify how much a stockpile weapon will cost to build.

float energyPerShot  default: 0.0

Energy used per shot. If the specified amount is not available, the weapon cannot be fired. Can also be used to specify how much a stockpile weapon will cost to build.

float myGravity  default: 0.0

Overrides the map gravity for ballistic weapons. The default of 0.0 disables the tag in favour of map gravity.

float fireStarter  default: 0.0

The percentage chance (0.0 to 100.0) of the weapon setting fire to static map features on impact.

float cameraShake  default: damage (0.0 for paralyzers)

Passed to the ShockFront() callin as the first argument. Intended as a means to make the camera shake if in range of detonation.

bool stockpile  default: false

Does each round of the weapon have to be built and stockpiled by the player? Will only correctly function for the first of each stockpiled weapons a unit has.

float stockpileTime  default: reloadTime

The time in seconds taken to stockpile one round of the weapon.

int interceptedByShieldType  default: Depends on weaponType

Bitmask representing the types of shields that can intercept this weapon. Each digit of binary that is set to one means that a shield with the corresponding digit in its interceptType will intercept this weapon. A value of 0 means that no shields will intercept the weapon. The defaults are as follows:

(See Shield Interception Tag Use).

Collision & Avoidance

bool avoidGround  default: true

Should the weapon avoid firing if terrain blocks the line of fire?

bool avoidFriendly  default: true

Should the weapon avoid firing if a friendly unit is in the line of fire?

bool avoidFeature  default: true

Should the weapon avoid firing if a static map feature is in the line of fire?

bool avoidNeutral  default: false

Should the weapon avoid firing if a neutral unit is in the line of fire?

bool collideEnemy  default: true lua: noEnemyCollide

Does the weapon projectile collide with enemy units or pass through?

bool collideFriendly  default: true lua: noFriendlyCollide

Does the weapon projectile collide with friendly units or pass through?

bool collideFirebase  default: false lua: noFirebaseCollide

Does the weapon projectile collide with friendly firebase units the owner is loaded onto, or pass through?

bool collideFeature  default: true lua: noFeatureCollide

Does the weapon projectile collide with static map features or pass through?

bool collideNeutral  default: true lua: noNeutralCollide

Does the weapon projectile collide with neutral units or pass through?

bool collideGround  default: true lua: noGroundCollide

Does the weapon projectile collide with terrain or pass through?

float collisionSize  default: 0.05 (0.5 for #Flame and #LaserCannon, 10.0 for #Dgun)

Modifies visual size of EMG and Flame projectiles, and physical size only for hitscan interceptor weapons (e.g. antinuke lasers). [1][2]

Targeting & Accuracy

bool commandFire  default: false

Determines if the weapon will automatically fire on enemy units in range or only when manually ordered to attack.

bool canAttackGround  default: true

Determines if the weapon can be force-fired on ground positions or only fire on targeted units.

bool waterWeapon  default: false

Determines if the weapon can pass through water and target underwater units.

bool fireSubmersed  default: waterWeapon

Determines if the weapon can fire whilst underwater.

float targetBorder  default: 0.0 (1.0 for #Melee)

Controls whether the weapon aims for the centre or the edge of its target's collision volume. Clamped between -1.0 - target the far border, and 1.0 - target the near border.

float cylinderTargeting  default: 0.0 (1.0 for #Melee)

Controls whether the weapon range is calculated in a sphere or a cylinder. The height of the cylinder is determined by the value of this tag multiplied by the range. Clamped between 0.0 and 128.0.

float tolerance  default: 3000.0 (+/- ~18 degrees)

The amount (in cau) to which the weapon's "real" aim can be off while the weapon will still be able to fire accurately at the target. For turret = false or fixedLauncher = true weapons this determines in what arc the unit will fire.

float fireTolerance  default: 32768.0 (+/- 180 degrees)New in version 99.0

Final check to prevent weapons from shooting sideways. If a weapon is about to fire but the difference between its old aim and requested aim is greater than this angle (in cau) then it will not fire.

bool allowNonBlockingAim  default: falseNew in version 99.0

When enabled it makes AimWeapon() script calls non-blocking (still the fireTolerance tag might prevent the weapon firing). This is very useful for fast units that need to re-target often.

float targetMoveError  default: 0.0

The degree to which a weapon's aiming will fail to keep up with its target's movement. It adds a fraction of the target's speed (per second) as a random error to the targetting. So if the target moves 50 units per second and the targetmoveerror is 0.5 a random error of 25 will be added to the target position. If set very low or not set at all, a weapon will lead its target and almost always hit.

float leadLimit  default: -1.0

Limits the maximum distance a unit will lead a target. The default of -1 allows an infinite distance.

float leadBonus  default: 0.0

Controls how experience boosts the weapon's target leading. Is multiplied with the unit's experience and added to the leadLimit.

float predictBoost  default: 0.0 (0.5 for burnblow = true weapons)

Controls how well the weapon predicts unit speeds. Works in a similar way to targetMoveError except that it is 1-dimensional. This tag spreads the shots in a line based on the direction of the target whereas targetMoveError spreads the shots all around based on the movement.

float heightMod  default: 0.2 (0.8 for #Cannon, 1.0 for #BeamLaser and #LightningCannon)

Changes the spherical weapon range into an ellipsoid. Values above 1.0 mean the weapon cannot target as high as it can far, values below 1.0 mean it can target higher than it can far. For example 0.5 would allow the weapon to target twice as high as far.

float proximityPriority  default: 1.0

Acts as a multiplier for the distance to the target in the priority calculation. Note that negative values make weapons prefer distant targets.

float accuracy  default: 0.0

How accurate the weapon is. Lower values are more accurate. Accuracy is relative to the distance to the target; for instance, if the target is very close, even a very high value will probably still hit. If a target is very far away, even a very low value will likely cause the weapon to miss.

float movingAccuracy  default: accuracy

A weapon's accuracy whilst the owning unit is moving.

float sprayAngle  default: 0.0

How wide the the angle of a burst from a burst weapon can be. Very similar to accuracy, except that this tag affects each projectile in a burst, whilst the former does not.

float ownerExpAccWeight  default: 0.0 (See description)

A multiplier to accuracy and sprayAngle that reduces inaccuracy as a units experience increases. Defaults are as follows:

int targetable  default: 0New in version 92.0 Previously only for #StarburstLauncher

Bitmask representing the types of weapon that can intercept this weapon. Each digit of binary that is set to one means that a weapon with the corresponding digit in its interceptor tag will intercept this weapon. Instant-hitting weapons such as #BeamLaser, #LightningCannon and #Rifle cannot be targeted.

int interceptor  default: 0New in version 92.0 Previously only for #StarburstLauncher

Bitmask representing the types of weapons that this weapon can intercept. Each digit of binary that is set to one means that a weapon with the corresponding digit in its targetable tag will be intercepted by this weapon.

bool interceptSolo  default: trueNew in version 92.0

If true no other interceptors may target the same projectile.

float coverage  default: 0.0New in version 92.0 Previously only for #StarburstLauncher

The radius in elmos within which an interceptor weapon will fire on targetable weapons.


bool waterBounce  default: false

Does the weapon bounce on water impacts?

bool groundBounce  default: false

Does the weapon bounce on ground impacts?

float bounceSlip  default: 1.0

The decimal-percentage amount of horizontal velocity a projectile keeps when it bounces.

float bounceRebound  default: 1.0

The decimal-percentage amount of vertical velocity a projectile keeps when it bounces.

int numBounce  default: -1

The number of times the weapon will bounce on impact before exploding. The default value of -1 allows infinite bounces (at least until velocity reaches 0).

Area Of Effect, Impulse & Cratering

float areaOfEffect  default: 8.0 * 0.5 lua: damageAreaOfEffect

The diameter in elmos in which the weapons explosion will cause damage.

float craterAreaOfEffect  default: areaOfEffect * 0.5

The radius in elmos in which the weapons explosion will cause terrain cratering. Behaviour changed slightly in 98.0 as previously craters were 1.5x craterAreaOfEffect whilst decals were 1.0x, they are now both the same size.

float edgeEffectiveness  default: 0.0

Determines what percent of a weapon's maximum damage value will be applied to units within the weapon's areaOfEffect. Falls off from the epicentre according to the formula damageApplied = damage * [(areaOfEffect - distToUnit) / (areaOfEffect - (distToUnit * edgeEffectiveness))], a graph of the function for various values is available here.

float explosionSpeed  default: See description

The speed at which the weapon's explosion propagates from the epicentre. The default is calculated by this complex formula: defExpSpeed = {8.0 + [max(30.0, default_damage / 20.0) * 2.5]} / {9.0f + [sqrt(max(30.0, default_damage / 20.0f)) * 0.7]} * 0.5.

float impulseFactor  default: 1.0

A multiplier to the impulse given to units within the explosion areaOfEffect, which is otherwise equal to the damage dealt after edgeEffectiveness is taken into account. For #Melee weapons this is instead multiplied by the owning unit's mass (See Gamedev:UnitDefs).

float impulseBoost  default: 0.0

A constant amount added to the weapon's impulse, regardless of distance from the epicentre or the damage potential of the explosion, prior to the application of impulseFactor

float craterMult  default: impulseFactor

A multiplier to depth of terrain crater the weapon's explosion will create, which is otherwise based on the damage potential.

float craterBoost  default: 0.0

A constant amount, added to the weapon's cratering depth before the application of craterMult.


int burst  default: 1 lua: salvoSize

How many shots to fire per burst.

float burstRate  default: 0.1 lua: salvoDelay

The time in seconds between shots in a burst. Note that reloadTime starts to count down from the first round fired, not the last so if reloadTime < burst * burstRate the weapon will fire continuously.

int projectiles  default: 1

How many projectiles released per shot (shotgun style). e.g. a weapon with burst = 5, burstRate = 0.5 and projectiles = 2 will shoot 5 lots of 2 for 10 projectiles total, with gaps of 0.5 seconds, before waiting for reloadTime. Best used in conjunction with sprayAngle or changing the firing piece using ShotX as otherwise they'll all be clumped in one shot.


bool paralyzer  default: false

Is the weapon a paralyzer? If true the weapon only stuns enemy units and does not cause damage in the form of lost hit-points.

int paralyzeTime  default: 10 lua: damages.paralyzeDamageTime

Determines the maximum length of time in seconds that the target will be paralyzed. The timer is restarted every time the target is hit by the weapon. Cannot be less than 0.

Dynamic Damage

The following set of tags allow for a weapon's damage potential to vary with the distance to its target.

float dynDamageExp  default: 0.0

Exponent of the range-dependent damage formula, the default of 0.0 disables dynamic damage, 1.0 means linear scaling, 2.0 quadratic and so on.

float dynDamageMin  default: 0.0

The minimum floor value that range-dependent damage can drop to.

float dynDamageRange  default: 0.0

If set to non-zero values the weapon will use this value in the range-dependant damage formula instead of the actual range.

bool dynDamageInverted  default: false

If true the damage curve is inverted i.e. the weapon does more damage at greater ranges as opposed to less.


bool soundTrigger  default: false (true for #Melee, #Rifle and non-beamBurst #BeamLaser)

Does the weapon play soundStart only once for each salvo (true) or for every round in a burst (false)?

string soundStart  default: ""

The name of a SoundItem (See Sounds.lua) or filename of a sound to play when the weapon fires.

string soundHitDry  default: ""

The name of a SoundItem (See Sounds.lua) or filename of a sound to play when the weapon collides with solid ground. Note that a #BeamLaser will play this sound every frame of its lifetime.

string soundHitWet  default: ""

The name of a SoundItem (See Sounds.lua) or filename of a sound to play when the weapon collides with water. Note that a #BeamLaser will play this sound every frame of its lifetime.


string cegTag  default: ""

The name, without prefixes, of a CEG to be emitted by the projectile each frame.

float intensity  default: 0.9 (0.2 for #Cannon)

Alpha transparency for non-3D model projectiles. Lower values are more opaque, but 0.0 will cause the projectile to disappear entirely.

string model  default: ""

The filename of a 3D model to use when rendering the projectile. Note that only the root piece of a projectile model is rendered. Currently only for #Cannon, #LaserCannon, #MissileLauncher, #StarburstLauncher and #TorpedoLauncher.

bool explosionScar  default: false

Does the weapon's explosion leave a scar decal on the ground? For all types except #Melee and #Rifle.

bool alwaysVisible  default: false

If true the weapon is always rendered regardless of whether or not it is in LOS range of a player's units.

float[3] rgbColor  default: {1.0, 0.0, 0.0} (See Description)

The primary colour for sprite rendering weapons. Additional defaults are as follows:

string explosionGenerator  default: ""

The name of a CEG, with custom: prefix, to spawn as the weapon's explosion. Does not currently work for #Melee and #Rifle.

string bounceExplosionGenerator  default: ""

For weapons which can use groundBounce = true, the name of a CEG, with custom: prefix, to spawn when weapon the bounces.

string texture1  default: ""

The projectile texture for #AircraftBomb, #Cannon, #EmgCannon, #Flame; beam texture for #LaserCannon, #BeamLaser, #LightningCannon; flare texture for #MissileLauncher, #StarburstLauncher and dome texture for the #Shield.

string texture2  default: ""

The end-of-beam texture for #LaserCannon, #BeamLaser and smoketrail texture for #MissileLauncher, #StarburstLauncher.

string texture3  default: ""

Flare texture for #BeamLaser, or muzzle texture if largeBeamLaser = true. Also used as the flame texture for #StarburstLauncher.

string texture4  default: ""

Flare texture for #BeamLaser with largeBeamLaser = true.


Drops a ballistic projectile at the same movement vector as the unit itself. Intended only for aircraft. Visually drawn as a billboarded sprite as used by the #Cannon, but more commonly used with a 3D model.

There are no tags specific to this WeaponType

AircraftBomb Visuals

When not using a model, the AircraftBomb is the same as #Cannon Visuals.


An instant-hit weapon which spawns a beam and does a portion of its total damage each frame. Cannot be script emitted if it has a beamTime longer than one frame. Visually drawn as a Star Trek Phaser-style laser weapon. The largeBeamLaser tag allows changing the visual effect of the laser, such as using a tileable, scrolling texture without changing the behaviour.

float minIntensity  default: 0.0

The minimum percentage the weapon's damage can fall-off to over its range. Setting to 1.0 will disable fall off entirely. Unrelated to the visual-only intensity tag.

float beamTime  default: 1.0 lua: beamtime (all lowercase!)

How long in seconds to fire the laser before waiting for reloadTime to start. Damage is distributed over the duration of the beamTime, and the weapon will aim to hit the target when the beam is in the middle of its beamTime (i.e. using prediction).

bool beamBurst  default: false lua: beamburst (all lowercase!)

Makes the laser fire a burst of beams that are all aimed towards the target (instead of aimed with the piece). A #BeamLaser can do its full damage with every shot if beamBurst is enabled. Disables beamTime in favour of the burst tags.

bool sweepFire  default: false

Makes the laser continue firing while it aims for a new target, 'sweeping' across the terrain. Reimplemented in 95.0, still has no script interaction so use with care. Respects reloadTime constraint but not much else.

BeamLaser Visuals

See also thickness and coreThickness.

int beamTTL  default: 0

The time in frames for which the laser beam remains visible.

float beamDecay  default: 1.0

How fast the beam fades out. Each frame the intensity is multiplied by this value.

float laserFlareSize  default: 15.0

Determines the size of the firing flare.

bool largeBeamLaser  default: false

Changes the visual effect allowing tiling and scrolling of the texture and a pulsating firing flare.

float tileLength  default: 200.0

Defines the length before the texture used is repeated (tiled). Only if largeBeamLaser = true.

float scrollSpeed  default: 5.0

Controls how fast the texture scrolls. Only if largeBeamLaser = true.

float pulseSpeed  default: 1.0

Controls how fast the pulsating effect at the start of the beam is. Only if largeBeamLaser = true.


The default WeaponType. Fires a ballistic projectile, for the best result (without under/overshooting) the weaponVelocity should be set so as to give an elevation of 45° when firing at the maximum range. Substituting the angle into the trajectory equation and rearranging, we get:

weaponVelocity = √(range * g)

where g is the map gravity, usually around 120 for most Spring maps (You can use the myGravity tag if you want to be exact). Visually drawn as a billboarded sprite or 3D model.

int highTrajectory  default: 2

Can this weapon be fired in a high trajectory (>45° angle). Can be 0 - low trajectory only, 1 - high trajectory only or 2 - enables a high/low toggle button on the unit.

float heightBoostFactor  default: -1.0

Controls the boost given to range by high terrain. Values > 1.0 result in increased range, 0.0 means the cannon has fixed range regardless of height difference to target. Any value < 0.0 (i.e. the default value) result in an automatically calculated value based on range and theoretical maximum range.

Cannon Visuals

float size  default: 2.0 + min(default_damage * 0.0025, areaOfEffect * 0.1)

The drawing radius of the billboarded sprite. Also for #AircraftBomb Visuals, #EmgCannon Visuals (default: 3.0) and #Flame Visuals.

string colorMap  default: ""

A set of RGB colours to transition between over the projectile's lifetime. Can be given as a string of RGB digits or an image filename (See CColorMap). Also for #Flame Visuals.

float sizeDecay  default: 0.0

How quickly each particle of the Cannon shot decays in size.

float alphaDecay  default: 1.0

How quickly each particle of the Cannon shot fades out.

float separation  default: 0.0

The distance between each particle of the Cannon shot.

bool noGap  default: true

Switch between the distance between particles being proportional to the size of the two particles (true) or proportional to the size of the first particle (false).

int stages  default: 5

The number of particles in each Cannon shot.


Fires a line-of-sight or ballistic projectile (selected via the gravityAffected tag). Visually represented by a fireball effect that cannot be customised, however it can be replaced by a 3D model. The name and visual effect are OTAisms.

bool gravityAffected  default: false

Does the fireball projectile lose height due to map gravity?


A line-of-sight weapon. Visually drawn as a billboarded sprite very similar to that of the #Cannon, however not as customisable, or a 3D model. The name is another OTAism.

There are no tags specific to this WeaponType.


A line-of-sight weapon intended for use as a flamethrower or similar. Visually drawn as a stream of textured particles, the colour of which can be controlled very precisely using the colorMap tag (see CColorMap).

Flame Visuals

See also colorMap.

float sizeGrowth  default: 0.5

How much the draw radius of the flame projectile increases each frame.

float flameGFXTime  default: 1.2

Makes the flamethrower projectile stay alive as a visual-only effect (i.e. does not deal any damage) after it has reached maximum range. It is a percentage multiplier, e.g. 1.2 makes the projectile stay alive until it reaches 20% beyond range.


A particularly versatile line-of-sight weapon. Visually drawn like a Star Wars Blaster-style laser weapon, or a 3D model.

LaserCannon Visuals

float duration  default: 0.05

Multiplied against weaponVelocity to determine the visual length of the beam projectile.

bool hardStop  default: false

Does the laser projectile stop dead or fade out?

float fallOffRate  default: 0.5

Rate at which the beam fades out after it goes past its maximum range if hardStop = false. A value of 0.0 is never fade out, 1.0 is finish fading out exactly at maximum range.

int lodDistance  default: 1000

Minimum camera distance at which the default LaserCannon projectile is simplified to a single rectangle.

float thickness  default: 2.0

The thickness (width) of the LaserCannon projectile. Also for #BeamLaser Visuals.

float coreThickness  default: 2.0

The thickness (width) of the LaserCannon projectile's core. Also for #BeamLaser Visuals.

float rgbColor2  default: {1.0, 1.0, 1.0}

The colour of the LaserCannon projectile's core. Also for #BeamLaser Visuals.


An instant-hit weapon similar to the #BeamLaser, but which does all its damage at once. Visually drawn like Star Wars 'Force Lightning' or CnC: Red Alert Tesla Coil weapons, the effect is not very customisable.

There are no tags specific to this WeaponType.


A weapon that always damages the target, no ifs or buts; unsurprisingly intended for use as a close quarters 'melee' weapon. It does not fire a projectile and does not care about the line of fire.

There are no tags specific to this WeaponType.


A versatile weapon which can optionally track targets and accelerate from a low initial velocity. It can also use trajectoryHeight to have the shot arc similar to a ballistic projectile. Visually represented by a 3D model, with an optional smokeTrail.

float startVelocity  default: 0.0

The initial velocity of the weapon projectile. Also for #StarburstLauncher and #TorpedoLauncher.

float weaponAcceleration  default: 0.0

The initial acceleration of the weapon projectile. Also for #StarburstLauncher and #TorpedoLauncher. Note that if it is 0.0 the weapon can never increase from its startVelocity and will not reach its maximum weaponVelocity. Since 99.0 acceleration is a synonym.

bool tracks  default: false

Can the weapon projectile track a moving target? Also for #StarburstLauncher and #TorpedoLauncher.

float turnRate  default: 0.0

The rate (in cau) at which tracks = true weapons turn towards their target. This is relative to a projectile's current velocity; a weapon with a higher velocity will need a higher value in order to be able to hit targets that turn suddenly.

float flightTime  default: 0.0

The time in seconds before a missile projectile's fuel runs out; it ceases to obey tracks, loses velocity and falls to the ground. Also for #StarburstLauncher. Large values may cause over/undershoot problems. As of 104.0 also applies to #EmgCannon.

bool fixedLauncher  default: false

Makes the projectile spawn with the orientation of the shooting piece instead of their normal orientation. Also for #StarburstLauncher and #TorpedoLauncher. Weapons may not correctly obey avoidance settings when using this tag.

float wobble  default: 0.0

Adds a random vector to the direction of travel every 16 frames, multiplied by the value of the tag. The effect is reduced as the firing unit gains experience. As this missiles direction is changed, wobbling swarm of missiles will diverge.

float dance  default: 0.0

Adds a random vector to the position of a missile projectile every 8 frames, multiplied by the value of the tag. As the projectile is not rotated, a dancing swarm of missiles will remain relatively coherent.

float trajectoryHeight  default: 0.0

Determines the height of the arc the missile will reach as it moves towards its target. A value of 0.0 will result in a flat trajectory, 1.0 will launch at 45°. Can be any value >= 0.0; extreme values may require the tracks tag to be able to hit a target.

MissileLauncher Visuals

A note about the missile exhaust flare: the size of the flare is determined by the model radius. The emit position of the flare is at (0,0,-radius) so the model may need careful adjustment to get the flare looking right.

bool smokeTrail  default: false

Does the missile projectile emit a smoke trail as it travels? Also for #StarburstLauncher.


An instant hit weapon which does all its damage at once. Visually represented by a hardcoded tracer, firing and hitting effects. Rarely used.

There are no tags specific to this WeaponType.

Shield (WeaponType)

As the name suggests, not a weapon but a defensive shield. Can absorb or deflect (repulsor = true) projectiles. Individual weapons can be set to be intercepted or not by the shield using a bitmask (see Shield Interception Tag Use). Visually represented as a translucent sphere, with control over colour and texture; by default the shield is invisible (visible = false).

See the #shield sub-table section for other tags specific to this type.


Fires a projectile that rises vertically for weaponTimer seconds, then turns towards its target. It can optionally track targets and accelerate from a low initial velocity. Before spring 92.0 was the only weapon that can be targetable and act as an interceptor. Visually represented by a 3D model, with an optional smokeTrail.

float weaponTimer  default: 0.0

The time in seconds during which the missile ascends vertically before turning towards its target.


Fires a projectile that will behave ballistically out of water and like a missile in water. Usually used with waterWeapon = true so they can fire underwater and target underwater units. An aircraft carrying a #TorpedoLauncher is a special case, the weapon turns into an #AircraftBomb projectile that will spawn a torpedo projectile on impact with water. Visually represented by a pointed black cuboid, usually the default object is replaced by a 3D model.

bool subMissile  default: false

Can the torpedo leave the water and target units and positions on land?


Not actually a WeaponType, but an individual weapon requested by Spring to 'fill in the gaps' if a unit claims to have a weapon which isn't actually defined. There needs to be only one of these weapons and it is created by setting weaponName = "NOWEAPON" rather than by the weaponType tag.

Sub Tables


The damage subtable lists how many hit points the weapon depletes against each armor class (See Armordefs.lua). It is a key-value map of armor class names and damage values. The special default entry is as the name suggests the default damage applied to any unit which does not belong to a listed armor class, or to shields.

For example a weapon which deals 100 damage by default but only 50 to units in the 'tank' armor class:

damage = {
    default = 100,
    tank = 50,


The preferred way to create a shield or repulser is to use the shield subtable rather than the old shield tags.

The following tags are repulser specific:

bool repulser  default: false

Does the shield repulse (deflect) projectiles or absorb them? Btw its not repulsOr, but repulsEr!

float force  default: 0.0

The force applied by the repulser to the weapon - higher values will deflect weapons away at higher velocities.

float maxSpeed  default: 0.0

The maximum speed the repulser will impart to deflected projectiles.

bool visibleRepulse  default: false

Is the (hard-coded) repulse effect rendered or not?

The following tags are general behaviour for all shields:

int interceptType  default: 0

Bitmask representing the types of weapons that this shield can intercept. Each digit of binary that is set to one means that a weapon with the corresponding digit in its interceptedByShieldType will be intercepted by this shield (See Shield Interception Tag Use).

string armorType  default: ""

Specifies the armorclass of the shield; you can input either an armorclass name OR a unitdef name to share that unit's armorclass.

bool smart  default: false

Determines whether or not projectiles fired by allied units can pass through the shield (true) or are intercepted as enemy weapons are (false).

bool exterior  default: false

Determines whether or not projectiles fired within the shield's radius can pass through the shield (true) or are intercepted (false).

float energyUse  default: 0.0

The amount of the energy resource consumed by the shield to absorb or repulse weapons, continually drained by a repulser as long as the projectile is in range.

float radius  default: 0.0

The radius of the circular area the shield covers.

float power  default: 0.0

Essentially the maximum allowed hit-points of the shield - reduced by the damage of a weapon upon impact.

float startingPower  default: 0.0

How many hit-points the shield starts with - otherwise the shield must regenerate from 0 until it reaches maximum power.

float powerRegen  default: 0.0

How many hit-points the shield regenerates each second.

float powerRegenEnergy  default: 0.0

How much energy resource is consumed to regenerate each hit-point.

float rechargeDelay  default: 0.0

The delay in seconds before a shield begins to regenerate after it is hit.

The following tags control the visual aspects of the shield:

bool visible  default: false

Is the shield visible or not?

int visibleHitFrames  default: 0

The number of frames a shield becomes visible for when hit.

float[4] badColor  default: {1.0, 0.5, 0.5, 1.0} (Red)

The RGBA colour the shield transitions to as its hit-points are reduced towards 0.

float[4] goodColor  default: {0.5, 0.5, 1.0, 1.0} (Blue)

The RGBA colour the shield transitions to as its hit-points are regenerated towards its maximum power.

float alpha  default: 0.2

The alpha transparency of the shield whilst it is visible.


The customParams subtable of a WeaponDef allows the game designer to give their weapons 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


Some games may have most WeaponDefs integrated into their UnitDefs.

S44 and MC:L implement an OOP paradigm with inheritance.

'Balanced Annihilation' WeaponDefs

'Conflict Terra' WeaponDefs

'Evolution RTS' WeaponDefs

'Imperial Winter' WeaponDefs

'Journeywar' WeaponDefs

'MechCommander: Legacy' WeaponDefs

'Spring: 1944' WeaponDefs

'Spring Tutorial Game' WeaponDefs

'XTA' WeaponDefs

'ZeroK' WeaponDefs