ArmA III Ballistics Overhaul

[bakerman 247]

ACE3 arma config values are not on the level of Spartan's. Like Brisse mentioned ACE3 has its own ballistics simulation, which has its own set of values, however the regular values are still used. For example you still have 9mm rounds with ridiculous levels of penetration. Unfortunately Spartan's work often goes unnoticed by the modding community, many still follow BI's examples or make up values as they go.

[Brisse 78]

Yes, it is possible that the hit and caliber values in ACE3 need tweaking. External ballistics should be fairly good though.

[ruthberg 7]

ACE3 vanilla config values (especially hit and penetration) are on a hold, since I already asked Spartan to contribute proper values. No point to spent time on sth. that has already been done.

[Spartan0536 189]

hhhhmm, ok if what I understand about how BIS has penetration and hit, they do not need to be calculated per barrel length as the base should be automatically altered by velocity, so in terms of future development I should not need to calculate hit and penetration per barrel length which makes my job a bit easier if this is indeed true. That being said if the above is correct then I can give the ACE3 team everything they need for all their associated calibers in a relatively quick manner.

[bakerman 247]

Correct, no need to adjust for barrel length or typical range. Hit damage and penetration is purely ammo focused and linearly dependent on projectile velocity.

[Brisse 78]

Edit: Nevermind. Post removed. There was an explanation of typicalSpeed here that I made up, but I have since learned from a developer that it was wrong. See this post for correct explanation: http://forums.bistudio.com/showthread.php?192027-BI-Developer-REQUESTED-for-Ballistics-Question&p=2941533&viewfull=1#post2941533

Edited May 25, 2015 by Brisse

[Spartan0536 189]

Ok so here is my new official stance on my work in the future....

1. In reference to making my data publicly available, I will continue to do this albeit on a much much smaller scale.

Q1 : Why?

A1: I plan to work DIRECTLY with developers through LIVE chat means, either vocal, textual, or both as its much more efficient than waiting for someone to write a forum post. This also allows me to work on a more specific set of ballistics variables, say 2 developers need custom 5.56x45mm values, one at 16 inches bbl length and the other at 18 inches, right now its all guess work for the guy looking into one I have not provided, in most cases I have a calculator that allows me to adjust powder burn rates to get a calculated velocity for that round. I could go inch by inch publicly but the amount of time/work would just not be worth it in the end, I can make a bigger better impact by directly working with the developers to suit their needs as requested (within reason).

2. I will be OFFICIALLY assisting Ruthberg with ACE 3's ballistics as a SECONDARY coder/researcher.

Q2: Why only assist or be secondary?

A2: Ruthberg wrote his script code for ACE 3 and Advanced Ballistics however it still relies on BIS code for the penetration and damage values, this is where I come in as I deal with this data set all the time, my work will be combined with his and will be fully compatible, in fact they will perfectly complement each other. Since Ruthberg has done a vast majority of the work I will not claim to be a primary author just a secondary, and I am fine with that, I still get to make a positive difference in one of the biggest most well respected mods in ArmA/modding history.

[Zriel 12]

Great news!

[Defunkt 431]

Spartan; Robalo of ASDG_JointRails has agreed in principle to the idea of also curating a JointMagazines addon which might define a complete set of ammunition types and all of the usual magazines used by present-day, and ArmA's future-war, firearms; a modern JAM (the Joint Ammo & Magazines mod from OFP days). Given the uptake of JointRails and the current 'magazine-hell' I think we might reasonably expect most weapon addon makers to reference these rather than defining all of their own ammunition (though they would still be free to define their own 'specials').

The upsides to such a thing are massive;

- No more need for cobbled together magazine compatibility patches by the weapon makers or other third parties (which often aren't versioned or regularly maintained).

- Consistent ballistic performance across all firearms in ArmA 3.

Of course it's your data (now that it's soon to also include common Soviet rounds) that could provide the foundation and make all of this possible. As your values are also destined to appear in ACE3, the number of "can you make it ACE compatible" posts that this would circumvent is another big tick. Every weapon that referenced these ammunition classes would be already ACE compatible at the most fundamental level. If there were extra config values that needed to be entered for Ruthberg's enhancements then they could also be added here potentially.

Without getting into any procedural specifics (i.e. workflow, communication channels, naming conventions), how would you feel about this idea in principle? It would get your work to the widest possible audience through a single efficient channel.

[Spartan0536 189]

If Robalo goes for the JointMagazines project I will assist him where possible, however some developers still require a specific set of ballistics so my personal communications will be necessary. I will still keep this page updated just so people know what I am up to.

[tortuosit 486]

2. I will be OFFICIALLY assisting Ruthberg with ACE 3's ballistics as a SECONDARY coder/researcher.

Q2: Why only assist or be secondary?

A2: Ruthberg wrote his script code for ACE 3 and Advanced Ballistics however it still relies on BIS code for the penetration and damage values, this is where I come in as I deal with this data set all the time, my work will be combined with his and will be fully compatible, in fact they will perfectly complement each other. Since Ruthberg has done a vast majority of the work I will not claim to be a primary author just a secondary, and I am fine with that, I still get to make a positive difference in one of the biggest most well respected mods in ArmA/modding history.

Which is very good, thank you!

[Robalo 465]

If Robalo goes for the JointMagazines project I will assist him where possible, however some developers still require a specific set of ballistics so my personal communications will be necessary. I will still keep this page updated just so people know what I am up to.

Thanks !

Here's some work in progress based on your data: https://github.com/robalo/mods/blob/master/asdg_jam/config.cpp

[Defunkt 431]

If Robalo goes for the JointMagazines project I will assist him where possible, however some developers still require a specific set of ballistics so my personal communications will be necessary. I will still keep this page updated just so people know what I am up to.

Thanks Spartan, with your data, Robalo's config-nous and a little buy-in from weapon makers this could deliver a really meaningful community standard.

[Spartan0536 189]

Thanks guys I am honored to be apart of this, it should really help the community get a base for ballistics, and if we can get this coordinated with both ACE3 and CUP and Default, it will be the end all be all for magazine compatability, no more ridiculous BIS default ballistics 12.7x54 Subsonic 353% damage*cough* *cough*

[Robalo 465]

My plan for JAM is to do ammo and magazine classes for reference barrels only (eg. 20" for 5.56, 24" for .308 etc.).

Then we can play with negative initSpeed coefficients in weapon configs to adjust the muzzle velocity per weapon specs.

What do you think ? Will this work or will the resulting ballistics for weapons defined this way stray away too far from realistic ?

Otherwise having ammo and magazines defined for various barrel lengths would become a config nightmare to maintain and I'd like to avoid that.

[quickdagger 170]

My small contribution.

It was made for A2OA, but all G1 BC´s and muzzle velocities are up-to-date.

Sorry for the images.

Or you can have the full 200 pages manual here <- ALL FORMULAS ARE EXPLAINED IN DETAIL.

http://s9.postimg.org/iesm2969r/Slide82.jpg (114 kB)

http://s11.postimg.org/3kx510tib/Slide86.jpg

---------- Post added at 20:02 ---------- Previous post was at 19:54 ----------

BTW, I´ve done a simple experiment with a zero gravity bullet and Bakerman's Community Ballistics Calculator.

I´ve created the following A2OA (the A3 code comes from A2OA) experiment:

class CfgAmmo

{

/*extern*/ class BulletBase;

class Dagger_AUX: BulletBase {};

class Dagger_TEST_3: Dagger_AUX

{

airFriction = -0.000750;

coefGravity = 0;

typicalSpeed = 1; // Just to ensure the bullet is free to decelerate from 786m/s all the way down to 1m/s.

};

};

class CfgMagazines

{

/*extern*/ class CA_Magazine;

class Dagger_TEST_1: CA_Magazine {};

class Dagger_TEST_3: Dagger_TEST_1

{

initSpeed = 786; // That 786 I spoke of.

ammo = "Dagger_TEST_3";

};

};

Then I went to Kronzi Fire range (http://www.kronzky.info/targetrange/) and shot targets 1800 m away. At that distance values must be ultra accurate for a .308, so I use it just to make sure my calculations are right.

Kronzi tells me targets are hit at an average of 371m/s. Remember there´s no influence of gravity, so only airfriction is acting.

Then I´ve calculated decelation using the formula:

v^2 = Vo^2 + 2*a*ds

371^2 = 786^2 + 2*a*1800

a = -132,5m/s^2

Then I went to Bakerman's Community Ballistics Calculator (http://www.armaholic.com/page.php?id=25287), inserted a = -132,5 and it calculated AirFriction = -0,000215 by using the formula:

Deceleration = Airfriction*muzzle veocity^2

But I have inserted Airfriction as being -0,00075.

What´s wrong?

Edited May 22, 2015 by QuickDagger

[Spartan0536 189]

The problem for me even without compensating for bullet drop is the atmospheric conditions that the ArmA III engine uses. This is why I claim to be within a 3%-5% threshold, and in RARE occurrences such as pistols I can get it down to 1% because the distance is much shorter.

Here are major contributing external factors to ballistics that I do not know about ArmA III:

1. Atmospheric Pressure

2. Temperature

3. Humidity

4. Elevation - However I have made a solid educated guess as to it being 0 due to the "island" nature of ArmA's maps

Now perhaps if a BIS DEVELOPER WOULD COMMENT ON THIS GIVING ME/THE COMMUNITY THE INFORMATION MISSING, WE WOULD ALL BE GREATLY APPRECIATIVE *hint hint* *nudge nudge*

*Addendum: Worst case scenario and they did not take any account into these values, then it would be BIS's error in coding ArmA III for how drag affects projectiles.

[quickdagger 170]

They should equation the ICAO atmosphere and bring an Airfriction modifier which uses a formula with height-pressure-temperature-humidity and comes up with the modifier, which should the percentage change from the mean conditions.

About Bakerman´s sim you are all using to calculate the new Airfriction,

I´ve entered:

ticker = 0.05

gravity = 0

angle of correction = 0 MOA

Airfriction = -0.00075

Muzzle velocity = 786

For the closest result to 1800 m it gave me:

t = 4.95

Range = 1801

(F) Velocity = 201

Then I went to the game and fired the 0 gravity round and it gave me:

t = 4.81

Range = 1800

hit velocity = 374

What´s wrong?

Since both times were close and the speeds were too different I presume there must have been some deceleration/acceleration somewhere. But where? Since I´ve zeroed gravity? There should be only airfriction acting on a perfect horizontal path.

[Spartan0536 189]

They should equation the ICAO atmosphere and bring an Airfriction modifier which uses a formula with height-pressure-temperature-humidity and comes up with the modifier, which should the percentage change from the mean conditions.

About Bakerman´s sim you are all using to calculate the new Airfriction,

I´ve entered:

ticker = 0.05

gravity = 0

angle of correction = 0 MOA

Airfriction = -0.00075

Muzzle velocity = 786

For the closest result to 1800 m it gave me:

t = 4.95

Range = 1801

(F) Velocity = 201

Then I went to the game and fired the 0 gravity round and it gave me:

t = 4.81

Range = 1800

hit velocity = 374

What´s wrong?

Since both times were close and the speeds were too different I presume there must have been some deceleration/acceleration somewhere. But where? Since I´ve zeroed gravity? There should be only airfriction acting on a perfect horizontal path.

Welcome to my world, I have been trying to figure this out for the better part of a year. The fault is not with Bakermans calculator, its within the ArmA III ballistics portion of their engine, I have no idea what their variables are set to nor do I know where to look for that data. This is the primary reason why Ruthberg made his mod where he introduces an entirely new set of ballistics calculations that make the bullets fly as realistically as possible, however there is a significant performance hit when getting into automatic weapons firefights as there is lots of calculative strings running.

There are 2 sets of ballistics standards to choose from ICAO and Metric, there are signifigant differences between the two, perhaps they are not using ICAO but metric, hell they use metric in their code why not using Metric for their ballistics, I will provide the data for standardized metric & ICAO ballistics variables below. BTW I am revising ALL of my ballistics to incorporate either the new ballistics standard of either ICAO or Metric, which ever one is more accurate to real ballistics tables.

ICAO

Barometric Pressure - 29.921 Hg

Temperature - 59F

Relative Humidity - 0%

Elevation - 0

Metric

Barometric Pressure - 29.5275 Hg

Temperature - 59F

Relative Humidity - 78%

Elevation - 0

Addendum: Since you are using a zero gravity formula your bullet would have different acceleration and time as bullets do not fly in a straight line but in a parabolic arch, this affects velocity and time.

Edited May 22, 2015 by Spartan0536

[ruthberg 7]

My plan for JAM is to do ammo and magazine classes for reference barrels only (eg. 20" for 5.56, 24" for .308 etc.).

Then we can play with negative initSpeed coefficients in weapon configs to adjust the muzzle velocity per weapon specs.

What do you think ? Will this work or will the resulting ballistics for weapons defined this way stray away too far from realistic ?

Yes, this is will work. And that's what I would suggest.

Otherwise having ammo and magazines defined for various barrel lengths would become a config nightmare to maintain and I'd like to avoid that.

This.

[Spartan0536 189]

Yes, this is will work. And that's what I would suggest.

This.

As long as the different bullet types are available and their performance is correct, I am fine with a more streamlined system. I am not sure how many guns you can alias with different velocities with different rounds but if it simplifies the code I am all for it.

[ruthberg 7]

The problem for me even without compensating for bullet drop is the atmospheric conditions that the ArmA III engine uses.

Vanilla Arma does not correct for atmospheric conditions (air density) at all!

Now perhaps if a BIS DEVELOPER WOULD COMMENT ON THIS GIVING ME/THE COMMUNITY THE INFORMATION MISSING, WE WOULD ALL BE GREATLY APPRECIATIVE *hint hint* *nudge nudge*

There is no information missing. The vanilla drag function is fully described by this: https://community.bistudio.com/wiki/Weapons_settings

The acceleration (m/s^2) that acts on the projectile at any given moment of time is given by:

drag = airFriction * velocity * velocity

The fault is not with Bakermans calculator, its within the ArmA III ballistics portion of their engine, I have no idea what their variables are set to nor do I know where to look for that data. This is the primary reason why Ruthberg made his mod where he introduces an entirely new set of ballistics calculations that make the bullets fly as realistically as possible

I made my mod to replace the simplified Arma physics model.

There are 2 sets of ballistics standards to choose from ICAO and Metric, there are signifigant differences between the two

Are you kidding me?

a) Arma does not model air density

b) The difference between the ICAO and ASM "standard" is by no means significant (reference: http://www.frfrogspad.com/bcdata.htm)

-> All of this is only relevant if you simulate atmospheric conditions.

Besides: Neither the ICAO nor the ASM (Army Standard Metro) standard are "metrical".

---

@QuickDagger (and everyone else who is interested):

I would like to invite you to join our public slack chat channel:

https://ace3public.slack.com/message...ed_ballistics/

You can get yourself invited here:

https://github.com/acemod/ACE3/issues/429

[quickdagger 170]

Hey Ruthberg,

Oh man, it sounds great!

Count me in :D

Hey Spartan,

Welcome to my world, I have been trying to figure this out for the better part of a year.

...

Addendum: Since you are using a zero gravity formula your bullet would have different acceleration and time as bullets do not fly in a straight line but in a parabolic arch, this affects velocity and time.

My pleasure man. Well, unfortunately we are not talking about real life but about the engine. And look what I´ve found:

I´ve done the same test as the one I described on the previous page, but this time adding gravity and the projectile hit the target at the very same speed of 374. And for a .308 at 1800 m we are talking of a huge parabola!!!!

So, I presume airfriction might be affecting only the x axis. But need more tests.

Edited May 23, 2015 by QuickDagger

[ruthberg 7]

So, I presume airfriction might be affecting only the x axis. But need more tests.

airFriction drag always acts in the opposite direction of the velocity vector.

The gravity force is 9.8066 m/(s^2).

@QuickDagger, what are you trying to do btw?

Edited May 23, 2015 by Ruthberg

[Spartan0536 189]

Vanilla Arma does not correct for atmospheric conditions (air density) at all!

There is no information missing. The vanilla drag function is fully described by this: https://community.bistudio.com/wiki/Weapons_settings

The acceleration (m/s^2) that acts on the projectile at any given moment of time is given by:

drag = airFriction * velocity * velocity

I made my mod to replace the simplified Arma physics model.

Are you kidding me?

a) Arma does not model air density

b) The difference between the ICAO and ASM "standard" is by no means significant (reference: http://www.frfrogspad.com/bcdata.htm)

-> All of this is only relevant if you simulate atmospheric conditions.

Besides: Neither the ICAO nor the ASM (Army Standard Metro) standard are "metrical".

---

@QuickDagger (and everyone else who is interested):

I would like to invite you to join our public slack chat channel:

https://ace3public.slack.com/message...ed_ballistics/

You can get yourself invited here:

https://github.com/acemod/ACE3/issues/429

Ruthberg, I was not speaking about in ArmA's engine but in using an external ballistics calculator like JBM Ballistics or Hornady Ballistics Calculator in which you use calculated numbers and real ballistics charts to simulate real drag performance by matching the airfricton value with real drag based on set atmospheric conditions. BIS does not (or at least I seriously hope they do not) just make up random airfriction numbers in their ballistics, it has to be calculated and this is the only means I know of that produces accurate numbers when dealing with BIS default code.

Addendum: As far as significance goes for atmospheric conditions regarding ICAO or ASM, when plugging in the data to calculators to get an airfriction value it can change the drag coefficient about 2-3% which then invalidates my claim on having accurate ballistics within a 5% threshold, this to me is significant, in terms of real world ballistics depending upon the distance, and round, it can be significant or insignificant.

Edited May 23, 2015 by Spartan0536