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Turret damage: Difference between revisions

From EVE University Wiki
Attempted a rewrite of several unclear parts (that i was originally guilty of, oh the shame)
m minor fixes, mostly rephrasings
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==Hit chance==
==Hit chance==
A turrets chance to hit a target is calculated from several parameters. The resulting value is between 0 and 1, or 0% and 100% if you will.  
A turrets chance to hit a target is calculated from several parameters. The resulting value is between 0 and 1, or 0% and 100% if you will.  
The hit chance of a turret is given by formula
The hit chance of a turret is given by this formula


<math>\pagecolor{Black}\color{White}\text{Chance to Hit} = {0.5^{\left({\left({\frac{V_{angular} \times 40000m}{WAS \times sig_{target}}}\right)^{2} + \left({\frac{max(0, Distance - opt_{turret})}{fall_{turret}}}\right)^{2}}\right)}}</math>
<math>\pagecolor{Black}\color{White}\text{Chance to Hit} = {0.5^{\left({\left({\frac{V_{angular} \times 40000m}{WAS \times sig_{target}}}\right)^{2} + \left({\frac{max(0, Distance - opt_{turret})}{fall_{turret}}}\right)^{2}}\right)}}</math>


V<sub>angular</sub> is angular velocity (sideways movement between the attacker and the target, expressed as an angle (in radians) per second)
V<sub>angular</sub> is angular velocity (sideways movement between the attacker and the target, expressed as an angle (in radians) per second)


WAS is weapon accuracy and means how well the turret can track a moving target, higher is better
WAS is the turrets tracking value (listed on the info window) and means how well the turret can follow a moving target


sig<sub>target</sub> is target signature radius (aka target size, a big target is easier to track)
sig<sub>target</sub> is target signature radius (aka target size, a big target is easier to track)
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Those who like math may recognize that the hit chance equation has the form ''x''<sup>(''a''+''b'')</sup>, which can also be written as ''x<sup>a</sup>x<sup>b</sup>''. In our case, x = 0.5, a = all tracking terms and b = all range terms. In other words, the hit chance equation can be thought of as having two separate parts, which are multiplied at the end to get the final hit chance. This means that tracking and range can be treated as two seperate things.
Those who like math may recognize that the hit chance equation has the form ''x''<sup>(''a''+''b'')</sup>, which can also be written as ''x<sup>a</sup>x<sup>b</sup>''. In our case, x = 0.5, a = all tracking terms and b = all range terms. In other words, the hit chance equation can be thought of as having two separate parts, which are multiplied at the end to get the final hit chance. This means that tracking and range can be treated as two seperate things.


One more thing we can learn from the equation is that the loss of hit chance due to falloff and due to tracking share the exact same behaviour. So by understanding how falloff works, one also understands how tracking works, even if it's not immediately obvious.
One more thing we can learn from the equation is that the loss of hit chance due to falloff and due to tracking share the exact same behaviour, since they both look like ''0.5''<sup>(something / x)<sup>2</sup></sup>, where x is either tracking or falloff. So by understanding how falloff impacts the damage, one also understands how tracking impacts it, even if that's not immediately obvious.
Example: At optimal+falloff a turret has 50% chance to hit. Against a target with the same angular velocity (rad/s) as a turrets tracking multiplied with the targets size and divided by 40 000 (the resulting number is in rad/s too), a turret has 50% chance to hit.
 
Difficult example: At optimal+falloff a turret has 50% chance to hit. Against a target with the same angular velocity (rad/s) as a turrets tracking (multiplied with the targets size and divided by 40 000) (rad/s), a turret has 50% chance to hit.


===Falloff and optimal range===
===Falloff and optimal range===
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===Turret tracking===
===Turret tracking===
Tracking is a value that represents how well your turret can follow a moving ship. The equation is not fully realistic, it doesn't consider if the attacking ship is spinning around itself, it only considers the relative movement between the attacker and the target. This relative movement can from the attackers point of view be looked at as a change of the angle to the target, this angular speed can be seen on the overview. But don't make the mistake of thinking that a turret can hit a target just because it can turn fast enough to follow the angular speed of a target, it would be realistic if it could, but it's not how the equation works. Instead it behaves just like falloff, so when the turret turns as fast as the target moves, the chance to hit is 50%. This also means that the turret has a chance to hit a target that is moving faster than the turret can turn.
Tracking is a value that represents how well your turret can follow a moving ship. The equation is not fully realistic, it doesn't consider if the attacking ship is spinning around itself, it only considers the relative movement between the attacker and the target. This relative movement can from the attackers point of view be looked at as a change of the angle to the target, this angular velocity can be seen on the overview. But don't make the mistake of thinking that a turret can hit a target just because it can turn fast enough to follow the angular velocity of a target, it would be realistic if it could, but it's not how the equation works. Instead it behaves just like falloff, so when the turret turns as fast as the target moves, the chance to hit is 50%. This also means that the turret has a chance to hit a target that is moving faster than the turret can turn.
With the updates to tracking, the behaviour remained the same, but some variables have been changed to make it easier to compare the tracking ability of turrets. Unfortunately it also made tracking a bit harder to understand, since the turrets own turn speed (in rad/s) is no longer visible and hard to compare against the targets angular velocity (in rad/s). To get a turrets tracking value (in rad/s) so that it can be compared to the targets angular velocity (in rad/s) the following equation must be used:
With the updates to tracking it became easier to compare the tracking ability of turrets, but also a bit harder to understand how it works, since the turrets own turn speed is no longer visible and therefore hard to compare against the targets angular velocity that is visble in the overview. To get a turrets tracking value (in rad/s) that can be compared against to the targets angular velocity (in rad/s) the following equation must be used:


turret tracking in rad/s = WAS x Target Signature Resolution / 40000
turret tracking in rad/s = Turret tracking x Target Signature Resolution / 40000
 
There is of course no time or need to use math in combat. But it is helpful when one is trying to figure out what the actual effect a bonus or a penalty to tracking would have. As stated earlier, falloff and tracking follow the same behaviour, so a +10% bonus to tracking will have the same proportional impact on hitting a moving target, as would a +10% bonus to falloff have on hitting a target out in falloff range.


Turret tracking is visible in turret info window. It is modified by skill, ammo, modules, hull bonuses and incoming tracking disruptors.
Turret tracking is visible in turret info window. It is modified by skill, ammo, modules, hull bonuses and incoming tracking disruptors.


Note that the turret tracking was recently changed. Any info that mentions turret signature resolution is outdated (they used to be 40m for small turrets, 125m for medium turrets and 400m for large turrets, now they all have 40000m).
{{expansion past | The "Turret Tracking" attribute in the formula used to be split into "Turret Tracking" and "Turret Signature Resolution". Combining them to single mumber simplified the formula without changing any mechanics. If you need to calculate turret hit chance with "Turret Signature Resolution" (for example using old NPC attribute info) just replace 40000 with "Turret Signature Resolution"}}
 
====Angular velocity====
This can be a tricky concept. Instead of measuring the speed as m/s or miles/hour, a speed can also be measured as the percieved change in the angle to an object from a certain location. A good example is the suns movement across the sky, where it moves 360° in 24 hours. If the sun is moving away or towards us is irrelevant, that wouldn't change the angle, only sideways movement will.


===Angular velocity===
This can be a tricky concept. Instead of measuring the speed as m/s or miles/hour, it can be also be measured as the percieved angular movement of an object from a certain location. A good example is the suns movement across the sky, where it moves 360° in 24 hours. If the sun is moving away or towards us is irrelevant, that wouldn't change the angle to it, the only thing important is the sideways movement which changes the angle.
Just as a circle can be described as an angle of 360°, it can also be described as an angle of 2&pi; radians. Meaning that one radian equals to (360/2&pi;) roughly 57°.
Just as a circle can be described as an angle of 360°, it can also be described as an angle of 2&pi; radians. Meaning that one radian equals to (360/2&pi;) roughly 57°.
The ingame overview can show the angular velocity of a target if you open the settings and tick a box under the tab called columns. Angular velocity is used to determine the penalty to the hit chance based on the turret's tracking ability. Relying on high angular velocities to stay alive is called speed tanking (not to be mixed up with kiting, which is to keep something at range). If an enemy is orbiting you, it is possible to use special maneuvers (like keep at range) or modules (like a web) to try to reduce the angular velocity, this will make it easier to hit an otherwise hard to track target.
 
The ingame overview can show the angular velocity of a target if you open the settings and tick a box under the tab called columns. Angular velocity is used to determine the penalty to the hit chance based on the turret's tracking ability. Relying on high angular velocities to stay alive is called speed tanking (not to be mixed up with kiting, which is to keep something at range). If an enemy is orbiting you, it is possible to use special maneuvers (like keep at range) or modules (like a web) to try to mess with the angular velocity, this can make it easier to hit an otherwise hard to track target.


Angular velocity is calculated as ω=v<sub>t</sub>/d, where v<sub>t</sub> is tranversal velocity of the target relative to shooter and d is distance to target. The shooter and target will both have same angular velocity to each other.
Angular velocity is calculated as ω=v<sub>t</sub>/d, where v<sub>t</sub> is tranversal velocity of the target relative to shooter and d is distance to target. The shooter and target will both have same angular velocity to each other.


===Target Signature Radius===
===Target Signature Radius===
Every ship is treated as a sphere when they are being shot at. The target signature radius describes how big this sphere is. This is only important when a turret needs to track the target. It has no impact on range.
Every ship has a size that is treated as a sphere when they are being shot at. The target signature radius describes how big this sphere is. The signature radius is only used in the tracking part of the hit chance equation. So it only matters for tracking, it has no impact on the loss of hit chance due to long ranges.


Target signature radius is visible in ship fitting window. It is modified by modules, hull bonuses and incoming target painters.
Target signature radius is visible in ship fitting window. It is modified by modules, hull bonuses and incoming target painters.
{{expansion past | The "Turret Tracking" attribute in the formula used to be split into "Turret Tracking" and "Turret Signature Resolution". Combining them to single mumber simplified the formula without changing any mechanics. If you need to calculate turret hit chance with "Turret Signature Resolution" (for example using old NPC attribute info) just replace 40000 with "Turret Signature Resolution"}}


==Damage==
==Damage==
All turrets have a base damage, which is a fixed number. The damage that a turret deal will be randomly spread around this value. The base damage is calculated from the turret's Damage Multiplier attribute, the ammo's damage values and the pilots skills.  
The damage that a turret deal will be randomly spread around a fixed value called base damage. The base damage is calculated from the turret's Damage Multiplier attribute, the ammo's damage values, hull modifiers and skills.  


DPS stands for Damage Per Second. This number is calculated from the average damage per hit that you do (if your hit chance is 100%) divided by the turret's rate of fire (ROF). The fitting window in the game will show you your DPS from turrets, drones and missiles respectively.
===Randomness of damage===
At the heart of each turret's damage output is a single randomly generated value between 0 and 1 that is several digits long. This random number is used '''both''' to determine if the turret hits the target and then to determine how much damage that hit actually did. If the random number is less than 0.01 (1% chance) it is a perfect hit and deals 300% of the base damage. A funny result of this is that when the hit chance is 1% or less, only misses and perfect hits can occur.


===Randomness of damage===
The damage modifier of the shot is calculated with the following formula, the first 0.01 of the random number interval is used for perfect hits which has a damage modifier of x3:
At the heart of each turret's damage output is a single randomly generated value between 0 and 1 that is several digits long. This random number is used '''both''' to determine if the turret hits the target and then to determine how much damage that hit actually did. If the random number is less than 0.01 (1% chance) the hit is a perfect hit and deals 300% of the base damage. A funny result of this is that when the hit chance is 1% or less, only misses and perfect hits can occur.


The damage modifier of the shot is calculated with the following formula, the first 0.01 of the random number interval will be used for perfect hits with a damage modifier of x3:
Damage modifier = Random number[0.01,1] + 0.49


Damage modifier = Random number[0,1] + 0.49
The base damage is multiplied by this modifier to get the final damage. A turret with a 100% chance to hit will strike for 50% - 149% of its base damage in every non perfect hit. Since the same random number is used for determining a hit and doing the damage calculations the upper damage interval also goes down when the hit chance is decreased. Which means that the average damage done is reduced more than the hit chance.


The base damage is multiplied by this modifier to get the final damage. A turret with a 100% chance to hit will strike for 50% - 149% of its base damage in every non perfect hit. Since the same random number is used for determining a hit and doing the damage calculations the damage interval also gets lower when the hit chance decreases. With a 70% hit chance a turrets damage interval is 50% - 119% of base damage with the non perfect hits, this means that the average damage done is not 70% but actually 59.8%.
Example: With a 70% hit chance a turrets damage interval is 50% - 119% of base damage with all non perfect hits, so the average damage done is not 70% of base damage, it is just 61.3% (69%*(50%+119%)/2+1%*3) of the base damage.


The quality of the hit is also visible on combat log.
The quality of a hit is also shown in the combat log.


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