Turret damage: Difference between revisions

This article takes a closer look at the To-Hit-Equation which is the fundament for all turret based damage dealing. Rather than focusing on the equation itself, the aim is to give the reader a general understanding of what comes out of the equation. This can be used to find a golden limit for how far tracking and falloff can be pushed while still keeping a high DPS. There will also be an explanation how the random damage distribution of turrets works, and why hard to hit targets are struck for less damage. As well as some guidelines for how damage modules and tracking modules can be compared if you know what kind of angular velocity the target has.

If you get a headache by just looking at this, don't worry, you will never have to actually do anything with it. And there will not be a test. It is however important, since it always works behind the scenes whenever someone uses a turret based weapon. But it isn't really the equation itself that is of interest in a fight, it is how it affects the fight. So that is what we will be looking at.  

An example of how this is useful, is with autocannons. They have very short optimals and large falloffs, so in practice they always fight in falloff. So the question is, how far can one go into falloff without having any major loss in damage? The equation can tell us this.

But now we have rushed ahead. We should start with the very basics, by looking at the components inside the equation, its variables, so we see what it is that actually effect the chance to hit. Most of these variables are determined before you undock. From your choice of ship, your skill points and your fitting. There are in fact only two variables that are based on how you actually fly your ship in space, those two are Transversal speed and Range To Target. Remember this. How you fly have a direct impact on the damage from turret weapons.

Now let's look a little closer at the equation itself, there is something to be learned from that:

Why is this interesting? From this we can see that tracking and range are actually calculated completely seperately before the results from each are multiplied. This means that Range and Tracking are two separate terms and can not replace eachother. Short range can never be made up for with good tracking, and vice versa.

There is one more thing we can find out by just looking at the equation. This is however a little tricker to grasp. The aim here is to compare the tracking term and the range term for similarities in their behaviour. Do they have anything in common? To do this, we will freeze all values in those terms except for one variable in each, tracking and falloff respectively. Then we can look at how that single variable effects the outcome and if there is any similarities between the two cases.

All guns have their tracking value expressed in something called angular velocity, this is identical to Transversal speed divided by Range to Target, this is inside the tracking term, and basically it means how fast something moves around something else. Lets freeze the angular velocity, this means that it is still moving but that the value will not change. In the tracking term we also have Turret signature resolution divided by Target signature radius, for easy comparison later on we will assume that both these number are the same, then we freeze them as well. What we are left over with is: a frozen number divided by Turret tracking.

Now lets look at the range part. Being inside optimal never incurs a hit penalty, so we must move out into falloff ranges too see any changes in the to-hit-equation's output values. Lets freeze everything apart from falloff. What we are left with is: a frozen number divided by Falloff.

Did you see what they had in common? In the tracking term, we now have ''something / Turret tracking'', in the range term we have ''something / Falloff''. In both cases there is a value that is divided by the variable we are interested in. That means that tracking and falloff behave in the same way. So if you understand how falloff works, you also understand how tracking works, even if you haven't realized it yet.

All turrets have a base damage, this is a fixed number. The higher the number the more damage the turret will do when it hits. It is calculated from the turrets Damage Multiplier attribute and the ammo's damage values. This is before any resistances is taken into consideration. A high base damage means that your guns hit hard (but do not mistake this for DPS (damage per second) since that also depends on how often the guns may fire). The base damage is always a bit below the average damage (about 1.5% lower) when there is a 100% hit chance -- the reason for this are those rare but highly damaging perfect hits.

A small gatling laser turret fires on target. The chance to hit is 0.8981. The EVE server rolls a random number between 0 and 1, and gets 0.6573 -- this is less than the chance to hit so the shot lands on the target. At this point 0.49 is added to the random number which then becomes 1.1473. The turret had a damage multiplier of x2.1 and the ammo does 4 EM and 2 Thermal, so the base damage is 2.1 multiplied with 6 (4+2), which is 12.6. After multiplying this with the random number we get the raw damage, which is 1.1473 x 12.6 = 14.456. In this damage the raw EM part is 1.1473 x 2.1 x 4 = 9.6373 and the raw Thermal part is 4.8187 (half of EM). Assuming the target's shield was hit, and that only the normal 20% resistance to Thermal is in effect, the final damage then becomes 9.6373 + (4.8187*(100%-20%)) = 13.492 points. In the combat log the hit will be described as 'well aimed' and be rounded off to one decimal place.

If you read the previous section, you may remember that the a random number between 0 and 1 is generated to see if a turret hits. If this value is higher than the chance to hit, the turret misses. What this really means, is that the random rolls that would have caused high damage becomes misses instead. This can be seen in the damage log: a hard-to-hit target never recieves excellent or well aimed hits, sometimes barely scratching is the highest possible (though of course perfect hits can still happen).  

The table below shows how damage and DPS goes down as a result of lower hit chance. The decrease is identical for tracking and falloff so either one can be used.  If you wish to combine the effects of tracking and falloff, look them up individuall and then multiply them (note: this only works for the columns Hit Chance and Relative DPS; the clumn Reduction in DPS by % can not be used for this).

Especially the 0.333 value is good to remember (one third of your tracking or falloff). Know your guns and know how far you can push them. If you want to maintain a high DPS, this is how deep you can go into either tracking or falloff (if you are pushing both use 0.25 instead). If you go outside it, your DPS will start dropping and if you go further in there is only a small increase in damage. This is kind of the golden limit that comes out from studying the To-Hit-Equation. Like all guidelines, this one comes with an exception too, see the next section for that.

If you know how many parts into tracking a certain ship is, and you want to adjust for the signature part too, you must multiply ''parts into tracking'' with ''Turret Signature Resolution / Target Signature Radius'' to get the ''true'' parts into tracking. There is no other way. This is not something that can be done in combat, mostly because you will not know the signature radius of your target. But you can use gut feeling and guess from what you see. Shields tanks means a bigger ship, armor tank a normal size. And then you compensate as you see fit.

'''Example:''' A shield tanked and an armor tanked Rifter are fighting. The angular velocity is very high at about 0.5 and they both have a tracking of 0.49 with their 200mm autocannons. So we say one full part into tracking. They are using small guns which always has a Turret Signature Resolution of 40m. The shield tanked Rifter has a signature radius of 50m and the armor tanked one has 35m. From the shield tanked Rifters point of view, his opponant counts as being 1 x 40m/35m = 1.14 parts into tracking, where the DPS loss from turrets are about -70%. From the armor tanked Rifters point of view, his opponant counts as if being 1x 40m/50m = 0.80 parts into tracking, where the DPS loss from turrets are only -46%. The shield tanked Rifter pilot is at a disadvantage from just being bigger, his guns do only about half the damage compared to his opponant. If he doesn't compensate for this by flying in a way that reduces the angular velocity, he is likely to loose.

Weapon upgrade modules can improve raw damage, tracking and range. Making use of an increased range is fairly obvious. However, comparing tracking and damage can be harder to do.

The tricky thing with this comparison is that the need for tracking in a fight often varies depending on how the pilots fly their ships. So to make any sense of the following you must have some rough ideas of what you expect to be up against and what the angular velocity can be expected to be at. The only way to get that is through experience.

The effect from a web is hard to predict, since its use can change both the transversal speed and the range between the ships. Experience and practice will be your best guide here. The drawback with webs is that they can help your opponants tracking as well as your own. The most important thing with a web is its tactical benefits, the fastest ship can control the range.

Beam lasers have the highest DPS (damage per second) and artillery cannons have the highest damage per hit (per volley). Both of these things are valuable, especially in PvP. High DPS is goood because it makes tough ships die faster. A high damage per hit is also good because it can instantly kill a target (something that is important when the target has logistic support that repairs it). Railguns on the other hand have only the second best DPS and the worst damage per hit. The good things railguns have are the fastest firing speed and a slightly longer range than beam lasers.

One must also look at the ammo each type of turret use. Lasers use crystals, changing them is immediate and they never run out of ammo. Projectiles use various ammo types that deal different damage types, which makes it easier to match the damage with the target. The hybrid ammo on the other hand is stuck with the same two damage types (like lasers are) and have a reload time (like projectiles do), if one feel a little mean one could say that hybrid ammo combines the worst of the other two types.

Beam lasers and artillery cannons have drawbacks too of course. Generally speaking: The beam lasers uses a lot of capacitor energy and require immense amounts of power grid, they will only really work on Amarr ships. The artillery cannons also needs a lot of power grid and are designed to be used on ships with a bonus for projectil firing speed, otherwise it takes forever before they can shoot again. So for Gallente and Caldari ships, the railguns will still be the overall prefered pick. They still have the second best DPS, so they are not horrible.

The collected data shows that the normal damage is distributed within 50%-149%. Since the first 1% unit is used for critical rolls (this is most likely, if the last % unit was used additional calculations will be needed if the to it chance is less than 1%), this means that the constant has to be 0.49.