Difference between revisions of "Basic PvP Mechanics"

Revision as of 06:44, 29 June 2009

Copyright Sanfrey Statolomy & Agony Unleashed

Introduction

Eve players don't play for long before running into the term "Signature Radius". Most develop some idea about what this means, but this - and some related terms - takes on a new importance when players become concerned with killing each other.

Understanding the terms explained in this article will help you deliver more damage to your enemies, avoid taking damage from them unnecessarily, and understand the impact of EWAR.

Signature Radius

It is easy to see by comparing different ships that the signature radius is relative to the ship class. At first glance the number, measured in metres, seems to simply give players an impression of how big each ship is. However there’s much more to it than that! The signature radius of a ship influences how much damage it takes from guns and missiles, how easy the ship is to scan out, and how quickly it can be locked.

Everything’s Round
Imagine trying to throw a sandwich at a Stop sign. There’s an easy way – face on, so you’re throwing it at the front of the sign; and a hard way – side on, where the sign is only a few millimeters across, and the largest target’s probably the post the sign’s nailed to.

Now imagine trying to shoot a Tempest battleship. Tall and long, the Tempest should be much easier to hit ‘side on’ than from the front as it has a much larger cross section when viewed sideways. (See diagrams 1 and 2 below.) Eve doesn’t work this way; the clue is in the term signature ‘radius’. Eve sees all ships as spheres, for the purposes of treating them as targets. As far as Eve is concerned, your battleship is just a well armed ball with a 400m radius! (Diagram 3.)

1. 2. 3.

As you’ll read below, it’s preferable to have a small signature radius. The larger a ship’s signature radius, the more damage it is prone to take, the faster enemies can find it with scan probes, and the quicker it can be target locked.

Things that increase Signature Radius

• Shield Rigs
• Shield Extenders
• Microwarpdrives (only when turned on)
• Being hit with a Target Painter
• Inertia Stabilizers

Things that decrease Signature Radius

• Training “Shield Rigging” skill (Only when using Shield Rigs)
• Training “Interceptors” skill (Only when flying Interceptors)
• Training "Electronic Attack Ships" skill (When flying a Hyena)
• Halo implants
• Skirmish Warfare links

Considering the lists above it’s easy to see that increasing a signature radius (which is bad) is much easier than decreasing it!

Signature Resolution

All guns in Eve have an ‘area of effect’ similar to that of a shotgun, or an artillery shell. Imagine shooting a tennis ball from 30 feet away with a shotgun – sure, the ball would get blown to pieces, but it would only have been hit by a few of the pieces of shot. Most of the shot would have spread out a little and missed the tennis ball.

In Eve, it’s easy to imagine this being the case with a blaster – after all, they spray out hot plasma and it’s intuitive that it could spread. However even artillery shells in Eve have this ‘area of effect’, known as the Signature Resolution. One way to think of this is to think of the artillery shell as an explosive charge – similar to real life artillery, they don’t simply hit something like a bullet does, they hit then explode. That explosion could be small or large, and on really big guns, the explosion’s really big.

The Signature Resolution of a gun measures the size of this area of effect in the same way that the Signature Radius measures the size of a ship. The relationship between the two determines how much of the gun’s damage the ship will take. (There are other factors too though!)

Our tennis ball example above describes the situation of a “Really Big Gun” shooting a little ship. For example, a 1200mm Artillery Cannon I has a signature resolution of 400m, and a Cormorant destroyer has a Signature Radius of only 90m. Therefore the Cormorant will only be subject to a small portion of the damage that the gun is trying to deliver, as the gun’s total damage will be spread over a circle with a 400m radius, and the destroyer is only 90m in size.

Explosion Radius & Velocity

The explosion radius is the missile’s equivalent to a gun’s signature resolution. In the same way that a gun has an area of effect, so does a missile.

A missile will hit for reduced damage if the explosion radius is greater than the ship's signature radius. For example a torpedo cannot hit for full damage against a frigate.

Also, a missile will hit for reduced damage if the ship's velocity is greater than the explosion velocity of the missile. This effect is combined with any reduction from the signature radius to explosion radius ratio.

Scan Resolution

The length of time it takes for one ship to lock another is determined by the targeting ship’s scan resolution, and the targeted ship’s signature radius. The higher the scan resolution, the faster a ship will lock onto targets; and the higher the signature radius of a ship, the faster other ships can lock it.

This is why a frigate can lock a battleship in very little time, but a battleship will take ten times longer to lock a frigate.

Imagine you are attempting to use a satellite to find a vehicle lost in a forest. The two things that will make the car easier to find will be the resolution of the satellite’s camera, and the size of the vehicle – a fire truck will be easier to find on a high quality, zoomed in picture than a motorbike on a low quality picture.

Sensor boosters improve scan resolution, allowing the ship carrying it to lock other ships faster. Sensor dampeners decrease the target’s scan resolution, thus increasing the length of time it takes for he or she to get a lock back.

Generally the Minmatar ships have the lowest signature radii, and also the highest scan resolution – making them the fastest to get target locks and the hardest to lock onto.

Sensor Strength

A ship’s sensor strength determines how difficult the ship is to jam, and how easy it is to find using probes. The chance of an ECM effectively jamming a ship depends on the strength of the ECM versus the target ship’s sensor strength.

Generally speaking the Caldari ships have the highest sensor strength and the Minmatar ships the lowest, making Minmatar slightly easier to jam than other races.

The sensor strength and signature radius of a ship both determine how easy the ship is to find using scanning probes. The two factors combine to what’s known as the ‘signal strength’. The higher the signal strength, the easier the target is to scan out.

For example, a rigged Vargur with only basic rigging skills will have a signature radius of 500m, and the paltry sensor strength of 11. The signal strength will be 500 divided by 11, which equals 45. This makes Vargurs incredibly easy to scan out with probes. In contrast the Rook has a sensor strength of 32 and a signature radius of 173, meaning its signal strength is 5 – nine times less likely to show up on a scanning probe.

Other factors such as the distance from the probe to the target, whether the target is in dedspace, and the probing pilot’s skills also contribute to the chance of a ship appearing on a scanner probe’s results list.

ECCM modules can be fitted to ships to increase their sensor strength, making them both more difficult to jam and more difficult to scan down. Be sure to fit the correct ECCM for your ship type!

Amarr – Radar
Caldari – Gravimetric
Gallente – Magnetometric
Minmatar - LADAR

Examples

This table compares the locking times of a few common ships. These are rough numbers, using the raw ship attributes without skills applied.

Nasty Maths

For the totally obsessed amongst you, here are the formulas behind the theories above. You do not need to know this stuff!

According to Akita T, the damage formula for turrets is:
z is the "To-Hit Chance", a number between 0 (0%) and 1 (100%)
x = random number between 0 and 1 (generated for each shot)

z = 0.5^{[Angular/ModifiedTracking]^2 +[(max(0,Range-Optimal))/Falloff]^2}
where Angular = Transversal/Range, and ModifiedTracking = TurretTracking * TargetSig / GunSig

If {x<0.01} Then {quality = 3} else {quality = x + 0.5}
If {x<z} Then {damage = quality x expected base damage} Else {missed shot}

In not so many words, what this means, is that :
* DPS goes down a lot faster as chance to hit does * chance to hit is never 100% whenever any transversal is involved * within optimal, after sig adjustments, if "adjusted turret tracking" equals target's angular velocity, you only have a 50% chance to hit, and you deal a bit under 40% DPS overall * you can get hit in a fast, small ship by a large gun with lousy tracking... it just has a very low chance to hit (but not zero)

According to Stafen, the damage formula for missiles is:
Damage = Base_Damage x MIN(MIN(sig/Er,1) , (Ev/Er x sig/vel)^(K x ln(drf)))

Where
sig = ship's signature radius
vel = ship's velocity
Er = Explosion Radius of missile
Ev = Explosion Velocity of missile
K ≈ 0.586
drf = damage reduction factor which changes according to missile type

drf for T1 missile types:
light = 2.8
rocket = 3.0
heavy = 3.2
heavy assault = 4.5
cruise = 4.5
torpedo = 5.0

According to Blazde, the time it takes for one ship to lock another is determined by:
seconds = ((40000 / ScanRes) / (asinh(SigRadius) ^ 2))

The chance for ECM to work, according to Trillian McMillan, is:
A / B = D
(100)D = E

A = ECM jamming strength for the intended sensor type
B = The target ships Sensor strength
D = Unfinal decimal of success
E = 100 times D, which will show you the final percentage.
Example against an Apocalypse:

6 radar jamming strength / 20 sensor strength on the apoc = .3 100 * .3 = 30

Multiple ECM formula:
Chance_to_jam = {1-[(1-E1)*(1-E2)*...*(1-En)]}*100 With Ez, E2... En being each of your jammers' chance to jam the ship.

If all your jammers are equal, E1=E2=En, of course, and the formula is:
Chance_to_jam = {1-[(1-E)^n]}*100
n being your number of jammers on the target.

Chance of being scanned out by a probe, according to Hoshi:
Signal Strength = (Probe Sensor Strength * (1 + Level of Astrometric Triangulation * 0.05) / 100) * (e^-((Target Range / Max Range)^2)) * (Target Signature Radius / Target Sensor Strength)