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External ballistics
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Description

It would be nice if you add external ballistics projectile: to wit
wind, vertical angles, temperature, pressure, and humidity.
Thanks in advance

Air temperature, pressure, and humidity variations make up the ambient air density. Humidity has a counter intuitive impact. Since water vapor has a density of 0.8 grams per litre, while dry air averages about 1.225 grams per litre, higher humidity actually decreases the air density, and therefore decreases the drag.

How this can be used in Arma 3: The airFriction would be changed depending on these factors.

Coriolis drift is caused by the Coriolis effect and the Eötvös effect. These effects cause drift related to the spin of the Earth, known as Coriolis drift. Coriolis drift can be up, down, left or right. Coriolis drift is not an aerodynamic effect; it is a consequence of flying from one point to another across the surface of a rotating planet (Earth).
The direction of Coriolis drift depends on the firer's and target's location or latitude on the planet Earth, and the azimuth of firing. The magnitude of the drift depends on the firing and target location, azimuth, and time of flight.

The Eötvös effect changes the apparent gravitational pull on a moving object based on the relationship between the direction of movement and the direction of the Earth's rotation. It causes subtle trajectory variations.
It is not an aerodynamic effect and is latitude dependent, being at its most significant at equatorial latitude. Eastward-traveling objects will be deflected upwards (feel lighter), while westward-traveling objects will be deflected downwards (feel heavier). In addition, objects traveling upwards or downwards will be deflected to the west or east respectively.

How this can be used in Arma 3: Depending on the direction and flight time of the bullet, small changes in the bullets flight path with be applied.

Details

Legacy ID
2243234098
Severity
None
Resolution
Open
Reproducibility
Always
Category
Gameplay

Event Timeline

VBS3 edited Steps To Reproduce. (Show Details)Jul 26 2013, 11:18 AM
VBS3 edited Additional Information. (Show Details)
VBS3 set Category to Gameplay.
VBS3 set Reproducibility to Always.
VBS3 set Severity to None.
VBS3 set Resolution to Open.
VBS3 set Legacy ID to 2243234098.May 7 2016, 3:41 PM

I think having to compensate for humidity and pressure is a little too much. Simple gravity drop and compensating for wind is realistic enough for me while playing a game.

How about making it settable through difficulty or mission settings? So that you could turn the more in-depth ballistics on or off?

I have no problem with it being added to higher difficulty settings or being optional. The only time that I could seeing this used would be with extremely long range sniper shots and artillery being effected by the Coriolis effect and gyroscopic drift.

VBS3 added a subscriber: VBS3.May 7 2016, 3:41 PM
VBS3 added a comment.Sep 3 2013, 6:51 PM

Ballistics in the simulator "arma" is the cornerstone.

Some of those effects (pressure,humidity)
are completely negligible for the arma environment.

Wind is usually not negligible gor accurate shots past 300 meters, but realistic wind estimation methods cannot be properly simulated. Just reading some windmeter and adjusting simply will not work in reality to the point where windmeters aren't very useful.

And if you want to have your rounds affected by pressure and humidity, they might as well add terminal ballistics.

We have a set Simul humidity command and a million other weather related commands, why not have it affect ballistics? Arma 3's penetration and ballistics is already miles ahead of pretty much every other game.

@DennisModem Terminal Ballistics is already a thing, check it on Youtube

I added some notes to the ticket description to make the ticket better than just "I want eternal ballistics".

Goose added a subscriber: Goose.May 7 2016, 3:41 PM
Goose added a comment.Nov 18 2013, 1:07 AM

I would say: priorities first!!!!

Before humidity, temperature, Coriolis effect, etc, we would need proper ballistics.

Right now it's just a single airFriction, and drag is proportional to the square of the speed. It's like fitting a straight line to a curve, it does not reproduce ballistics very accurately.

We would need multiple airFrictions for every projectile, or we would need a better drag model, neither are going to happen because it's too much work and no player will notice in-game if a bullet is going 360 m/s when it should be going 340 m/s at 1200 meters range.

Anyways, what about wind drift? That is a far bigger priority than Coriolis effect etc. Unless you are using artillery at 15km Coriolis effect will not play a big part in a bullet's flight, wind will, and we have no wind effects.

IMO the biggest things we need are airFriction as array and wind drift.

For the airFriction as array I mean something like this:

supersonic = -0.00096
transonic = -0.00120
subsonic = -0.00105

airFriction[] = {-0.00096, 408, -0.00120, 272, -0.00105, 0};

Gravity drop is already there, wind is neccessary, temperature, humidity, and pressure are WAY too much, and the change is not even that much.

Goose, even though you are right, these ballistics at least do just fine.

Using TOH Flight model even as an option would be a far bigger priority, or being able to jam your gun and using Barrel Heat to change the bullet path is also a bigger priority

I think wind drift is the single most important factor right now. At 500 meters you will have to offset your aim about a foot to compensate for a 15 mph cross wind (throwing rough numbers here because I don't feel like calculating it). This is important for making long range sniper shots.

There is a separate ticket for wind affecting bullets.

Goose added a comment.Nov 18 2013, 3:44 AM

For the wind drift, they could use the following formula:

x = w(t-(d/v))

where

x = drift
w = wind velocity
t = time of flight
v = muzzle velocity
d = distance

So example calculation for the .408 CheyTac M320 LRR

airFriction = -0.00049
initSpeed = 910
wind = 10 km/h at 90 degrees = 2.78 m/s

Time of flight 1000 meters = 1.41 sec

x = (t-(d/v))
x = 2.78(1.41-(1000/910))
x = 0.86 meters

Drift at 1000m = 0.86 meters

This formula is more than accurate enough for game purposes, of course it requires that the in-game times of flight match the real life times of flight.

Edit: didn't see ProGamer's response above.

the problem with that formmula is that it would need to calculate the distance and time of flight before impact or before leaving the gun barrel itself.

you would need the game to calculate things that are not happening yet.

Goose added a comment.Nov 18 2013, 5:31 AM

I did think of that, it could perhaps register the current time of flight and continuously adjust the bullet's position accordingly, although I don't know well how that would work in real time and with hit detection, etc.

In any case wind drift is dependent on lag time, the difference between actual time of flight, and time of flight in a vacuum.

IIRC the ACE mod uses a coefficient for each bullet for the wind drift.

Calculating wind drifts in real time shouldn't be a real issue. Making it true to the real life bullets and weather can be tough though.

Goose added a comment.Nov 18 2013, 9:05 AM

Personally I don't think it's a huge issue being 100% true to life, for example drift of 8.5 MOA in-game, when in real life it is 7.5, is acceptable. As long as it is reasonably correct I'm fine with it, it's more the method of calculation which would concern me, the principles of the physics should be correct.

danczer added a subscriber: danczer.May 7 2016, 3:41 PM

Demonstrating how Coriolis effects bullet drop at 1000 yards:
http://www.youtube.com/watch?v=jX7dcl_ERNs

I tottaly support idea. Humidity, coriollis has very marginal influence. Much more has temperature and altitude:
.408 Rocky Mountain 420gr 1500m//910m/s
humidity (%)temperature (C) altitude (m)drop(in)final speed(m/s)
0 0 0 -850.1 412.5
0 30 0 -804.6 443.4
100 30 0 -796.3 449.5
100 30 500 -767.4 472.3
0 0 500 -815.2 436.1

There is no problem for developers to make it work. It just need few lines of code and wheather condition simulation. Seriously.
Ballistic in arma works like this: every 0.001s based on airfriction and all other data in last interval, new acceleration, speed and position are updated.
All they have to do is change constant airfriction to live changeable based on conditions.
But you are naive if you think the will do this. Theire intrested in selling as much copies as they can. If this game turn more into simulator, they will loose a pile of money. So vote up maybe they'll change mind.
Before that check out AGM mode, soon its going to support external ballistics temp. ,altitude, wind etc.
Cheers

gibonez added a subscriber: gibonez.May 7 2016, 3:41 PM

Real life bullet ballistics would probably fundamentally change the game in a good way.

Gun fights will last longer, long range gunfights will be more chaotic and realistic.

Instead of 2 minute long gunfights at extended ranges, firefights could last 15 minutes or more.

Teamwork and logistics would play a huge role. All of this must be done and optimized straight from the engine however in order to get the best performance.

The improvements to gameplay are far too large to ignore.

gibonez I think you are putting your hopes up in the wrong place.

While ballistics in-game could use some improvements for the extreme ranges, the real reason firefights are quick and deadly is due to how easy it is to place your sights on target.

Check out the recent dev branch changes that are supposed to make shooting more challenging - Those are much more critical for what you would like, though IMO are still not enough (it is still too easy to get sights on target in many situations).

ArmA 2 firefights were longer and had the same thing. In arma 2 i could pick up a HOLO sight and shoot almost perfectly fine at 200 meters of range, in arma 3 i cant, although i kinda blame recoil too.

The reason why firefights barely last is because of the AI.

In ArmA 2 firefights ended much faster when comparing to firefights at the same range in ArmA 3. Aiming and hitting targets in ArmA 2 was quite a bit easier than in ArmA 3, and hitting stuff in ArmA 3 is quite a bit easier than real life.

When you can hit targets accurately, firefights are generally quite shorter.

Plus in ArmA 2 Takistan/Chernarus we had quite a bit less cover than we have on Altis.

This is of course talking from a PvP perspective. When it comes to AI of course the more AI the longer the firefight, and the less accurate they are the longer the firefight is too, but that is a configuration/scaling issue rather than shooting mechanics. AI configuration is completely off-topic here. First the players should be adjusted to behave realistically, then the AI can be configured to follow suite (and actually, you can already configure them with very simple scripting or user-friendly mods).

@ Galzohar

Those changes are indeed fantastic. I just see enhanced ballistics to add yet another layer to perhaps make the shooting more realistic.

meatro added a subscriber: meatro.May 7 2016, 3:41 PM