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| − | {{Weapon Systems Links}}
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| − | Gunnery has two main mechanics directly tied to it: Hit chance and turret damage. These two are linked together on many levels and having a basic understanding on the mechanics is important for anyone who flies a turret based ship in EVE.
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| − | =Hit chance=
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| − | [[File:QST_turret_range.gif|frame|right|alt=range animation showing falloff|<center>Range, falloff and chance to hit</center>]]
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| − | The basic question of shooting a turret is wether you will hit or not. In Eve, hitting with a turret is not quite a simple question of being either in range or out of range. Instead it depends on the concepts of optimal range, falloff and tracking. You can find figures for both of these if look at your fitted turret info.
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| − | Due to how the hit chance is calculated the range and tracking do not effect each other and can be considered separately.
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| − | ==range==
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| − | Every turret has two range parameters called "Optimal Range" and "Accuracy Falloff".
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| − | A gun's optimal rangeis the range within which distance has no effect on hit chance. In other words in optimal range the distances can be completely ignored and only tracking has any effect on hitting.
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| − | Accuracy falloff begins at the end of optimal range. Falloff measures how quickly the chance to hit decreases as the target distance grows ''beyond'' optimal range. At a gun's optimal range ''plus'' its falloff, the chance to hit is reduced to 50%. At a gun's optimal range plus ''twice'' the falloff range, the chance to hit is reduced to only 1/16. Since other factors can reduce this hit chance even further, at excessive ranges it is often not worth it at all to fire turrets, unless you're trying to draw aggression from a rat (which can be done at maximum targeting range).
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| − | So, for example, you're firing a gun which has 20km optimal range and 6km falloff at a target which is moving steadily straight away from you (zero transversal), starting at only 1km range. You will (if nothing else intervenes) always hit a target that is less than 20km (your optimal range) from you; your chance to hit will gradually decrease as your target moves between 20km and 26km (your optimal + falloff) from you, reaching 50% at 26km. By 32km (optimal + twice your falloff) your chance to hit will be down to 6.25% and decreasing.
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| − | The penalty for exceeding the optimal range by a small amount is reasonably low; the chance to hit a target at 33% of the falloff range in excess of the optimal range is still above 90%. Minmatar ships especially have signifigant falloff ranges allowing them to fight effectively beyond their optimal range. However, as the distance increases, the chance to hit decreases faster and faster.
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| − | When using turrets that fight inside falloff ranges it can be useful to know that being at optimal+(falloff / 2) results in -20% average damage and being at optimal+falloff results in -60% average damage (note: average damage falls faster than hit chance due to how the random damage interval is calculated, see below).
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| − | Falloff and optimal ranges are visible in the turrets info window. They are further modified by skills, ammo, modules, hull bonuses and incoming tracking disruptors. Target distance is visible on the overview.
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| − | ==Tracking==
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| − | Tracking is a bit more complicated concept than range due to larger number of variables, less intuitive variables, the player not seeing all the variables and chaotically changing variables.
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| − | The first variable is "Turret Tracking" value that is found in all turrets. This value that tells how well the turret tracks a target. Tracking of course depends on how fast the target moves, but instead of raw velocity you need to consider angular velocity. The problem here is that this depends on three other more basic variables, Velocity of shooting ship, velocity of target and distance, and can change very fast during combat. The third variable is target signature value that is often hard to know beforehand.
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| − | Due to being so hard to estimate it is often best to use [[Third-party tools|a Third-party tools]] to see how well your guns track moving targets. Bot he EFT and PYFA are able to draw damage application figures on moving targets.
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| − | The concept of turret tracking value is simple: The smaller a turret is, the faster its tracking speed will be: small autocannon, for example, track faster than medium autocannon. Short-ranged varieties of turret have better tracking than their long-ranged counterparts -- so, for example, medium pulse lasers track faster than medium beam lasers and large blasters track faster than large railguns. Doubling tracking and halving angular velocity have same effect on hit chance so webs and manual piloting are very effective at manipulating hit chance as seen in practical applications section below.
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| − | In chance-to-hit calculations, your guns' tracking speed is compared against your target's angular velocity and signature radius. Angular velocity is a geometric concept to do with radii of circles, but it can be hard to visualise. One way to think about it is to imagine that your screen's point of view in Eve is looking out above the barrels of your turret as it looks at your target -- a turret's-eye-view, so to speak. If your target was moving quickly across your turret's point-of-view, it would have a high angular velocity, and if it was moving slowly across your turret's point-of-view it would have a low angular velocity.
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| − | The ratio of your target's angular velocity to your guns' tracking speed is what's important. If their angular velocity is high, the ratio will be high, and you're very unlikely to hit them.
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| − | The speed at which a target moves across a turret's field of view doesn't depend only on the target's real velocity. The direction the target's moving in relative to the ship firing at it matters too: a ship that burns straight towards you could be quite easy to hit, regardless of its speed, because it's not moving very fast across your turrets' point-of-view. Range also affects angular velocity: a target orbiting you at 400m/s at a range of 7,000m has a much higher angular velocity than a target orbiting you at 400m/s at a range of 30km.
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| − | Note that the actual [[Turret Damage|mathematics of tracking]] make use of several formulae, and there can be quite a bit more involved than the basic summary here. Angular velocity itself depends on the ratio of transversal velocity and range (it's to do with the geometry of circles and radii) -- but it's easier to think about angular velocity since measurements of it in radians per second relate easily to the figures for gun tracking speed. Mathematically, we can talk of substituing the formulae into each other, so our ratio of angular/tracking becomes transversal / (range * tracking). You can find a brief explanation of the differences between angular and transversal velocity [[Overview Guide#The Columns Tab|here]] within our overview guide.
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| − | ===Speeding Up or Slowing Tracking===
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| − | You can increase your guns' tracking speed by fitting Tracking Enhancers in your low slots, or Tracking Computers in your mids, particularly if you load the latter with Tracking Speed Scripts. In your rig slots you can fit the appropriate (Energy/Hybrid/Projectile) Metastasis Adjusters for a 15% (20% tech II) increase in tracking speed, at the cost of higher power grid needs for your turrets.
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| − | Training levels in [[Skills:Gunnery#Motion_Prediction|Motion Prediction]] increases your guns' tracking speed.
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| − | Tracking Disruptors, as the name suggests, can reduce their target's gun tracking speed, especially when loaded with Tracking Speed Disruption Scripts.
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| − | ==Signature Radius==
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| − | Every ship in Eve has a [[signature radius]] (you can find a figure for yours on the fitting screen). Signature radius represents, roughly speaking, a ship's footprint on everyone else's sensors.
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| − | Here are some example signature radii:
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| − | * the Incursus (frigate) has a base sig radius of 44m
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| − | * the Caracal (cruiser) a base sig radius of 145m
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| − | * the Hurricane (battlecruiser) 240m
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| − | * the Abaddon (battleship) 470m
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| − | Base signature radii can be altered by various things: shield extenders, for example, increase your sig radius, while an active MWD boosts your sig radius by 500%.
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| − | In the chance-to-hit calculation, the target's current sig radius multiplies the weapon tracking attribute.
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| − | In fact, what happens is that the target signature radius feeds into the tracking calculation. If the target has minimal or no angular velocity (if, for example, both ships are sitting still, or the target is flying straight towards or away from the firing ship) then the tracking calculation has very little or no effect on the chance to hit, and therefore the target's signature will be irrelevant.
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| − | This is why it ''is'' possible for a rack of battleship guns to hit a frigate for (as they say) massive damage despite the frigate's very small signature: if the frigate sits still, or burns straight towards or away from the battleship, or is at a long enough range that despite its speed it doesn't have much angular velocity from the battleship's point of view, it is toast.
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| − | Since the tracking depends on all three: target signature radius, turrent tracking and angular velocity it can be hard to intuitively see when it is possible to hit. For example medium autocannon with 50 tracking shooting a cruiser with 150 m signature radius with angular velocity of 0.073 rad/s has 90% chance to hit. In same situation but when shooting at frigate with 50 m signatus the hit chance is only 39%.
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| − | {| class="wikitable" border=0
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| − | ! Hit chance from tracking || Angular velocity (rad/s) as a function of <br /> tracking (T) and signature radius (S)
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| − | | 50% || T×S/40000
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| − | |-
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| − | | 60% || T×S/47000
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| − | |-
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| − | | 70% || T×S/56000
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| − | |-
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| − | | 80% || T×S/70000
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| − | |-
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| − | | 90% || T×S/103000
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| − | |-
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| − | | 100% || 0
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| − | |}
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| − | ===Boosting or Reducing Signature Radius===
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| − | Target Painters increase their target's signature radius and (as mentioned already) microwarpdrives increase a ship's sig radius by 500% when active. (Except on certain t2 hulls, which have bonuses which reduce the sig bloom caused by MWDs.) There are implants (Halo) which reduce your ship's signature radius, but their effect probably doesn't justify their price unless you are very, very rich. X-insticnt drug reduces signature radius for more reasonable price but the effect is not long lasting.
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| − | ==Math==
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| − | A turret's chance to hit a target is calculated using the equation below. It will produce a result between 0 and 1, representing a probability between 0% and 100%. This value is then compared to a random number to see if the turret hits or misses.
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| − | <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>
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| − | ''V<sub>angular</sub>'' is angular velocity (movement between the attacker and the target expressed as an angle (in radians) per second)
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| − | ''WAS'' is the turrets tracking value (listed on the info window, previously called Weapon Accuracy Score) and means how well the turret can hit a moving target
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| − | ''sig<sub>target</sub>'' is target signature radius (aka target size, a big target is easier to track)
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| − | ''Distance'' is the range in meters
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| − | ''opt<sub>turret</sub>'' is optimal range of turret
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| − | ''fall<sub>turret</sub>'' is falloff range of turret
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| − | The hit chance equation has the form of ''x''<sup>(''a''+''b'')</sup>, which can also be written as ''x<sup>a</sup>x<sup>b</sup>''. In this 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 (tracking and range), which are calculated individually and then multiplied at the end to get the final hit chance. This means that tracking and range don't interfere with one another, they are indeed two seperate things.
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| − | The equation also shows that the reduction of hit chance from falloff and tracking respectively follow the same pattern. This is because they both look like ''0.5''<sup>(something / x)<sup>2</sup></sup>, where x is either tracking or falloff. The only differance between them are the input variables, the output look the same.
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| − | '''Example:''' At a range equal to optimal+falloff the range part of the equation becomes ''0.5''<sup>''1''</sup>, which means a 50% chance to hit. Against a target with the same angular velocity (rad/s) as a turrets tracking value multiplied with the targets size and divided by 40000m, the tracking part of the equation becomes ''0.5''<sup>''1''</sup>, which is also a 50% chance to hit. In the first case the full falloff range was used, in the second case the full turret tracking was used, and since they both follow the same pattern they end up at the same hit chance.
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| − | =Damage=
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| − | As was mentioned in this page's introduction, your chance of dealing good, more damaging hits ('wrecking' shots that deal more damage) decreases as your chance to hit decreases in falloff. This relationship is not linear, and your chance of good hits decreases quite rapidly as you move into falloff. At optimal + falloff, where your chance to hit is (as always, assuming other factors don't intervene) 50%, you can expect something like 40%, not 50%, of your theoretical maximum DPS.
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| − | [[File:Turret_HitChance_and_AverageDamage.PNG|650px|thumb|right|Click to enlarge]]
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| − | =Skills=
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| − | =Practical applications=
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| − | =References=
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| − | http://forum.eveuniversity.org/viewtopic.php?p=201888#201888
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| − | http://forum.eveuniversity.org/viewtopic.php?p=216525#p216525
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| − | http://www.hostile.dk/files/eve/eve-tracking101.swf
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| − | https://www.reddit.com/r/Eve/comments/5h24bk/turrets_listed_signature_resolution_is_40km/
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