Space Combat Mechanics
Starships versus System
Ships versus Orbitals
Starships are the default for ship stats. Hull size for hull
size, orbitals cost 60% of the AUs and get 150% of the space,
System ships cost 75% of the AUs and get 133% of the space.
Armor, Shields, and Hit Points
Things that get shot at by default have Hit Points equal
to their space. For some reason, ships have space available
equal to one less than their listed space; the amount of damage
to distroy a hull with a listed space of 200 is 200 points,
but you can only put 199 space of stuff in the hull. Fighters
have HP equal to their base space, which is 66% of the space
the interceptor form takes up and 33% of the space that the
SCF form takes up; this is entirely dependent upon the weapon
type of the fighter. Missiles have HP equal to the space a
single missile takes up (without counting in the +1 per-rack
surcharge; I have not tested whether armor piercing warheads
have more HP, though I assume that they don't).
The number of armor points a ship, fighter, or missile has
is based on its armor type and armor thickness. Armor for
fighters and missile always has the same "thickness."
Armor also has a deflection value, established by armor type
and modified by thickness. Armor never takes up space, regardless
of its thickness.
Shields have three combat-relevant stats, apart from their
size and cost. Each shield technology has a stopping percentage
(StpPow), a number of shield points (ShdStr), and a recharge
rate (Recharge), and except for the Damper Field they all
default to consuming 5% of the hull space of the ship they're
on (so shielding an Orbital takes up more space than shielding
a Starship). Shield generator sizes modify the shield points,
the recharge rate, and the space, but don't change the stopping
percentage. Missile and fighter shields have their own shield
Note: Shields and armor for fighters and missiles don't take
up space. Their cost "*= .33" seems to be interpreted
as just 0.33 AUs, and is affected by chassis.
How damage is applied to a target:
1) Take a particular weapon hit (so, a volley from 2 LFG's
that fire 5 times each time they fire would go through this
2) First, apply the effects of shields.
3) Now, apply the effects of armor.
- The shield absorbs a fraction of the damage equal to its
- Subtract that fraction from the shield points remaining
on the shield.
- The remainder, plus any absorbed damage that was in excess
of the remaining shield points, is passed on to the next
4) The damage falls on the hit points of the target. Subtract
the remaining damage from the hit points. Display the lesser
of that number and the number of HP that were present to take
the damage. If hit points are reduced to or less than 0, the
target blows up.
- If the amount of damage remaining is less than or equal
to the deflection value, the remaining damage is wasted.
If shields were damaged, display a blue number equal to
the number of shield points lost.
- Take a random number between 0 and 1.
- If the random number is less than the ratio of the remaining
armor to max armor, the remaining damage hits the armor:
subtract that many armor points. Display a yellow number
equal to the amount of damage that hit armor.
- If the random number is not less than the ratio, go on
to the last step.
In actuality, you only display damage per-volley, based on
the furthest penetration achieved by that volley.
Note: the shield recharge rate is misrepresented in game
as the number of shield points regenerated per 5 seconds;
the actual rate is per second.
Note: Armor piercing doesn't (shield penetrating does).
Direct Fire Weapons
Accuracy: The change to hit at or below
the minimum range (AccDisSt) for a DF weapon is the listed
maximum accuracy for that weapon. The chance to hit scales
down linearly to 60% of the maximum value at the maximum range
(AccDisEn); beyond this range the weapon will refuse to fire.
So, a weapon with an accuracy of .7, or 70%, has a 42% chance
of hitting at its maximum range. Some weapons (Stellar Converter,
Mauler) have their minimum range set to just under their maximum
range so as to produce an effect of no dropoff in accuracy.
Having an accuracy of greater than one (once accounting for
range dropoff) is treated like having an accuracy of 1.
Damage Dropoff: Most DF weapons don't do
their maximum damage when they hit their target. There are
two elements to this.
First, there's a range-based reduction. At or under a weapon's
minimum range for damage purposes (DmgDisSt), this reduction
is zero; the Base Damage is equal to the weapon's maximum
damage (NearDamg). The Base Damage scales down linearly from
there to the minimum damage (FarDamag) over the course of
twice the weapon's listed maximum range for damage purposes
(DmgDisEn). Thus, the Base Damage for a weapon is its minimum
damage at 2*DmgDisEn + DmgDisSt; the default weapons set always
has the maximum range for accuracy and damage the same, so
the actual minimum Base Damage for a weapon is close to the
average of the minimum and maximum damage, shifted towards
the maximum damage based on the relationship between the minimum
range and the maximum range.
The actual damage done is the Base Damage reduced by a random
factor. To determine the random factor, take the smaller of
the Base Damage and the damage delta (DmgDelta) stat. Multiply
this by a random number from between 0 and 1. Subtract the
result fro the Base Damage to determine how much damage is
By default, the damage delta stat is equal to the difference
between the maximum and minimum damage stats.
Mass-classsed weapons (Mass drivers, Rail guns, and the like),
have their minimum range for damage set to be just under the
maximum range for damage, so they have no dropoff due to range.
Furthermore, they have their damage delta set to 0, so there
is no randomized reduction.
Mounts change all of the stats mentioned above except for
the damage delta stat. Thus, mounts with larger multiples
on the damage stats (e.g. the Spinal series) suffer much smaller
proportional reduction in damage dealt from the random factor.
(Obviously, mass-classed weapons don't benefit from this effect.)
Note: The code is capable of handling cases with stat configurations
that are far from the defaults. DmgDelta can be much larger
than the NearDamg; FarDamag can be larger than NearDamg; AccDisEn
does not have to be the same as DmgDisEn; etc. These cases
all behave as described above.
Weapon Stats: Range and damage weapon stats,
as well as DmgDelta, are discussed above. Other weapon stats:
Mounts: Weapon mounts can change the four range
stats, the two damage stats, Dmgdelta, size, cost, ShldPen,
but not MultFire or MaxAcc. Since the PD mount claims to modify
MultFire, it's sort of broken.
- FireDlay: Seconds between weapon fires.
- Multfire: How many times the weapon fires when FireDlay
has elapsed. All Multfire shots hit the same target.
- ShldPen: When hitting shields, the shield's stopping percentage
is multipiled by this value; lower is better.
- ArmrPier: Has no effect.
Mods: Weapon mods are capable of altering:
MultFire, the four range stats, FireDlay, the two damage stats,
size, DmgDelta, and ShldPen.
All default missiles have 95% accuracy at all ranges, regardless
of what you change about their range stats; they always do
max admage, similarly regardless of what you change about
their range stats. They have ShldPen and ArmrPier stats, but
I haven't tested the former and assume that the latter doesn't
work (based on DF armor piercing not working).
The rate of fire displayed in the ship design screen is not
the actual rate of fire, but the multiplicative modifier to
the warhead's rate of fire, which are all 45 seconds by default.
The number of racks you have is the number of missiles you
fire in a volley; the number of missiles per rack is the total
number of volleys you can fire. The space a missile rack takes
up is proportional to 1 plus the number of missiles in it.
Once you have the tech for missile armor and shields, they
are installed by default on all missiles in new designs, but
the checkboxes aren't selected. To turn them off (not that
you'd want to outside of testing game mechanics), you have
to select then deselect the checkboxes.
The combat AI will happily launch missiles before having
a target for them, in which case they'll circle around the
launching TF until a target is detected. I believe that missile
launchers will not launch a second volley until the first
has at least acquired a target (perhaps even until the first
volley is gone).
As far as I know, the following fighter stats have no in-game
effect: ShieldDmg, MaxShrnk, MinFactr, MinimSize, HullDMod,
Fighters have HP equal to the base space, the amount they
take up before the *=1.5 multiplier for Interceptors or the
*=3.0 multiplier for SCFs is applied. The only difference
between SCFs and Interceptors is that SCFs take up twice as
much space and get a 40% increase in max damage and a 20%
increase in min damage.
Damage calculations for fighter weapons are handled in the
same fashion as for direct fire weapons. However, all fighter
weapons are listed with 3000 minimum range, and almost all
fighter combat happens under that distance.
The combat AI will happily launch fighters before having
a target for them, in which case they'll circle around the
launching TF until a target is detected.
I have noticed no difference between SCF AI and Interceptor
AI. It's conceivable that Interceptors will occasionally deign
to shoot at missiles and fighters while SCFs won't.
It is commonly reported in these forums that Interceptors
will not participate in planetary bombardment, but SCFs will.
Modding Note: I've found the following fighter weapon stats
to be not modifiable by the fighter chassis: Armor points,
DmgDelta, DmgDisSt, MultFire. This makes me strongly believe
that the only stats that fighter chassis can affect are the
ones it alraedy does (size, damage, and cost).
Sensors and ECCM multiplicatively reduce the OffTgtRg stat.
ECM and Cloak multiplicatively increase the DefTgtRg stat.
Cloak also increases the Cloaking stat.
None of this has any impact on weapon accuracy.
Apparently, this only affects visual detection. All my tests
on the subject have been far too noisy to draw any conclusions.
Da_Blade has claimed on these forums that a QS developer has
told him that there should be a deterministic visual detection
radius and that the randomized behavior is a bug.
Assuming Da_Blade's information is correct, this is my ex
recto theory as to how this is supposed to work. If I'm correct,
the shipbuilding AI's as broken on this subject as it is on
every other. Every theory I've come up with that bears any
resemblance to the tech stats and various descriptions is
fairly broken as a game mechanic...
Warning: Completely ex recto speculation follows
a) There is a base detection radius inside which you would
by default see anything. Target size may very well frob this
(i.e. "leviathans are easier to see than lancers").
b) Sensors increase this radius multiplicatively.
c) When a ship is attempting to see a target, their radius
for that purpose is reduced by the ECM and Cloak of that target.
d) That ship's ECCM will counteract the effects of the cloak
and ECM, but will not increase the effective detection radius
beyond the base detection radius.
e) If any ship on a side in combat can see a ship in a taskforce,
that entire taskforce is visible to all ships on the detecting
Warning: Completely ex recto speculation precedes
What the autobuild will pick for you, and thus what your
AI opponents use.
Armor and Shields
Class 0: No armor, no shields. Colony and Outpost ships are
Class 1: Minimal armor, minimal shields. The AI will take
your highest tech armor and best shields and put them in the
smallest mounts available (usually "very light"
armor and "small" shield generators). IF, CV, Recon,
and Transport are Class 1.
Class 2: Maximum armor, mediocre shields. For armor, you'll
get the highest tech in the heaviest form available. For shields,
you'll get your highest tech in the Standard generator. Point
Defense ships are Class 2.
Class 3: Maximum armor, maximum shields. LR, SR, and Planet
Destroyer ships are Class 3.
Note: "Highest Tech" above actually means "furthest
down the listings in TechTables." Since the Damper Field
is listed after all other shields, it will be chosen preferentially
over all other shields. Changing its position in the sequence
will change the preference.
If a ship is marked Stealth, it'll put the best cloak available
on. (Presumably, "best" once again means the one
furthest down the TechTables listing.)
LR, SR, and PD ships get one copy of a sensor or an ECCM.
I have not noticed a pattern as to which of sensors or eccm
are chosen, but the AI seems to only use the weakest one available.
Recon ships seem to get maxed out on thet highest tech of
Weapon and Mount choices
I've not investigated anything about the decisionmaking process
of picking which Planet Destroyer weapon to mount on a Planet
Destroyer ship. Each of SR, LR, and PD ship-types are listed
in TaskForceRules as trying to optimize a particular characteristic
(NearDamg, AccDisEn, and FireDlay, respectively). For simplicity,
I'm going to talk about the decisions based on SR/LR/PD. I've
not found another stat that you can plug in there that will
work (including FarDamag, which is listed as what IF TF's
are supposed to optimize) for DR autobuild choices.
I've not been able to determine what controls whether the
autobuild AI will include mods available for a weapon when
it decides to use that weapon. It seems to usually be pretty
happy to add mods to a weapon if they're available, and it
seems to often take those mods into account when making weapon-choice
decisions. This is an area I should test more. My hypothesis
is that it will strip away size-increasing mods to get smaller
weapons to look at if it can't fit the full thing into the
space available, but will otherwise preferentially add all
Point Defense ships: For the type of the primary weapon, it
picks the weapon with the smallest FireDlay (in general, every
weapon except the New Orion weapons has the same FireDlay
of 2.5 seconds). From any ties there, it chooses the weapon
with the highest base tech level. From any ties there, it
picks the weapon lowest on the TechTables list. It uses the
available mount highest on the list in TechTables. Once it
has stuffed as many of those in as it can, it will try to
fill in the remaining space by going down its list of "best
PD weapons" and finding the best one that will fit at
least one weapon in.
Long-Range ships: For the type of the primary weapon, it
picks the weapon with the highest AccDisEn. From any ties
there, it looks like it prefers the weapon with the smallest
InfoWeap number (the order weapons are listed in the weapons
table). For the mount, it selects the mount furthest down
the TechTables listing (since TechTables lists the PD, then
Light, then Standard, then the Heavy Series, then the Spinal
series, it will only pick Heavy series mounts for LR ships
if there are no Spinal mounts available). It then tries to
fill the rest of the space as listed in PD ships, above.
Short-Range ships For the type of the primary weapon, it
picks the weapon with the largest NearDamg. I haven't been
able to determine what governs choices between ties in this
case. It follows the same scheme for weapon mount choice and
secondary weapons as it does for LR.
Indirect-Fire ships It takes the largest warhead you've got
and puts it on the chassis furthest down TechTables. It then
fills in space with PD nukes. I haven't yet tested how it
decides to use PD nukes; I assume the PD chassis is selected
as the first listed in TechTables, nukes are probably chosen
as the first warhead listed in TechTables (and if there were
lower-listed warheads with smaller space, they'd presumably
be used in any case where the PD nukes wouldn't fit). It builds
Carriers It selects the fighter weapon listed last in TechTables,
and fills the carrier with SCFs of this type. It then fills
the rest of the space with Laser Interceptors. Predictably,
the SCF/interceptor choice is made by position in TechTables,
and it's also the case that Lasers are chosen as padding also
because of their position in TechTables.
Colony ships, Transport ships, and Outpost ships get autobuilt
with 60% of their max speed. IF ships get autobuilt at 80%
of max speed. Everything else gets full system engines.
At least until the code patch is out, there's a severe problem
that ships usually fail to acquire the first inbound volley
of missiles and/or fighters before they hit/start firing.
The best workaround that's been found is to make sure that
every ship you want to have firing PD has a missile rack with
Some people have claimed that loading up your PD ships with
sensors and ECCM will fix this; I've found minimal improvement
using this method compared to using the missile workaround.
Data Appendix - Click
Other useful tables by visage:
Damage efficiency of weapon/mount combinations at maximum
Damage efficiency of weapon/mount combinations at 50% of
maximum range: http://web.mit.edu/munch/www/moo3/middammetric.html
Percent damage done at maximum range, by weapon/mount: http://web.mit.edu/munch/www/moo3/fardropoff.html
Percent damage done at 50% maximum range, by weapon/mount: