Turret mechanics: Difference between revisions

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There are basically two things that affect your chance to hit a target with a turret-mounted weapon: range and tracking. This guide explains each factor in turn, and explores some of these factors' practical implications for combat. The second section looks at how the damage is calculated and how hit chance affects damage distribution. Having a basic understanding of the mechanics is important for anyone who flies a turret based ship in EVE, or wishes to avoid being hit by 1400mm artillery fire.

When a turret shot is fired, the game generates a random decimal number between 0 and 1. This number is then used in the '''[[#Hit Math|Hit Math]]''' and '''[[#Damage|Damage]]''' equations described below. This random number is used twice:

As can be seen, the lower the random number, the easier it is to hit - because the hit chance will always be above a low random number. However, when the random number is added to 0.49 it will end up in a low damage multiplier, so the shot will deal less damage when it does hit. The following sections go into more details about where these numbers come from and other implications of this system.

The basic question of shooting a turret is whether 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 all of these if look at your fitted turret info.

Due to how the hit chance is calculated the range and tracking do not affect each other and can be considered separately. A nice thing to remember is that against a stationary target the tracking part can be ignored while against a target that is in optimal range the range part can be ignored.

Every turret has two range parameters called "Optimal Range" and "Accuracy Falloff".

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 significant falloff ranges allowing them to fight effectively beyond their optimal range. However, as the distance increases, the chance to hit decreases faster and faster.

Tracking tells how well turrets hit a moving target. If the target is stationary relative to the shooter tracking is ignored and only range effects hit chance. If the target is both inside optimal range and stationary the turrets have 100% chance to hit. As a result against stationary target the turret tracking is irrelevant and even the largest turrets can hit the smallest targets if the target is foolish enough to sit still.

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.

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. There is only one value for tracking unlike the optimal and falloff for range. One way to look at it is to consider the turret to always being in "tracking falloff" with zero optimal tracking.

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).

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.

* Tormentor 35 m

* Thrasher 56 m

<pre>turret tracking (new) = Turret tracking (old) * 40000 m / Optimal Signature Resolution</pre>}}

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 between 0 and 1. By convention, the random number has to be less than the calculated result to hit. If the random number is greater than the calculated chance, the turret misses.

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''^{(something / x)²}, where x is either tracking or falloff. The only difference between them are the input variables, the output look the same.

'''Example:''' At a range equal to optimal+falloff the range part of the equation becomes ''0.5''^''1'', 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''^''1'', 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.

The damage that a turret deals 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. The base damage is the so called "paper damage" that is shown in all info windows. "Paper DPS" is simply "paper damage" divided by rate of fire.

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As was mentioned earlier, your chance of dealing good, more damaging hits ('smashing' shots that deal more damage) decreases as your chance to hit decreases. 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 40%, not 50%, of your theoretical maximum DPS.

'''Example:''' When the hit chance of a turret is 70% the damage interval has shrunk to 50% - 119% for all non perfect hits. When combined, these two things results in an average damage of just 61.3% (69%*(50%+119%)/2+1%*3) of the base damage.

No. Even if the guns are grouped on your screen, they are still treated separately. This can be seen by collecting damage data and comparing that with the expected damage distribution, it's very clear that it's a combination of several separate turret shots instead of a single one. It can also be deduced by looking at the turret group's damage output when shooting at hard to hit objects, like things deep into falloff, it's then possible to tell when one, two or more guns hit the target.

The hit chance and its relation to range, tracking, velocity and signature radius have many effects on combat with turret ships. Taking advantage of this knowledge allows you to control range, control velocities and choose the right modules for the job. This section gives several useful tricks and maneuvers for ships that either fight with turrets or against a turret ship.

Although you can use tools like EFT's DPS graphs, this knowledge comes partly with experience. It's much easier to figure out against NPC rats, which always have the same characteristics while kindly heading more or less straight for you until they close into their preferred orbit range, than it is with PvP enemies.

If your ship is faster and more agile, and the opponent is orbiting you, the angular velocity can be minimized (can reach zero) by using Approach. If your ship is slower or less agile, and the opponent is orbiting you, angular velocity can be minimized by using Keep at Range (if set to far away, but be warned: if you reach this range your ship will stop). Alternatively, if your ship has very poor agility, it is better to fly in a straight line to maximize your own speed and let the orbiting ship chase after you. Maximizing the angular velocity is harder but will happen if both ships orbit one another, or if one is using Approach but isn't agile enough to get behind the other. A ships agility is the multiplication of its inertia modifier and mass, a lower value means it can do sharper turns.

Shield extenders increases the signature resolution (size) of a ship, which makes them easier to track with turrets. Armor plates increases mass (slower turn speed) and reduces the top speed with afterburners and microwarp drives, which makes them easier to track too.

The conclusion from all the information about tracking speed and signature radius is: when you want to avoid damage, you want your angular velocity to be as high as possible and your signature radius to be low. But if you want to hit should probably try to fight within your guns' optimal range, but be prepared to fight within your optimal + falloff range (also called 'first falloff') if you must. One of the simplest yet important rules to remember is that two ships always have the same range and angular velocity towards eachother. The pilot who can control these two values, can control how much damage turrets will be able to do.

If you have a PvP fleet of large ships that are struggling to hit a swarm of smaller targets you may find it helpful to spread out, and order each ship to target the enemies furthest away from it. Even if your enemies are flying under your guns individually, you can use the low angular velocity provided by greater range to kill the small ships attacking your fleetmates, who can do the same to the small ships attacking you. (By the same token, large ships are most vulnerable to smaller enemies when they're on their own.)

For new pilots who are likely to be flying small fast ships one of the key ideas that follows from this is the tactic of 'flying under the guns' of an enemy ship: orbiting them at high speed and short range so it's very hard for their guns to track your small-signature ship. (Sometimes referred to as a form of 'speed tanking' or 'sig tanking'.) Assuming you're fast and small enough to survive under the enemy's guns, the main trick is getting there in the first place: if you burn straight towards the enemy, they will probably hit you (especially if you have an active MWD). If you approach a distant target straight on, there is no angular velocity, and the hit chance from the tracking term will be 100%. A battleship can easily hit a frigate for full damage if there is no need to track it.

# Zoom in reasonably close to your ship and press C to make your camera autofollow the selected enemy (alternatively center the camera on your enemy manually so that it covers up the enemy on your screen.)

# Now double-click in space halfway between your ship and the edge of the screen (in any direction).

# As it does so, every few seconds repeat double-clicking halfway between your ship and the edge of your screen. (If you are playing without autocamera repeatedly realign your camera so your ship goes back to blocking your view of the enemy, and each time you do so double-click halfway between your ship and the edge of your screen again.)

# This should make you spiral around them, moving ever closer until you can orbit (hopefully safely).

The Disruption EWAR module will reduce a turrets tracking and/or range. Since ships are often fitted around an idea, like fighting at a certain range, a disruptor can really mess with that. Always bring both range and tracking disruption scripts, you won't know which one you'll need until you are in combat.

* Against missile ships angular velocity is irrelevant, although a small signature and high speed still help you reduce damage from missiles; if you're only facing a missile ship, you could head straight for them

* Drone ships using normal drones (''not'' sentry drones) won't have a problem because their main damage dealing is coming from the drones, not any guns they have fitted

* Your enemy may have smartbombs, and medium and especially large smartbombs deal quickly with frigates; this is why rookie tacklers are advised to orbit large ships outside smartbomb range

https://www.reddit.com/r/Eve/comments/5h24bk/turrets_listed_signature_resolution_is_40km/