Armed Assault weapon ballistics

[USM-75R.Hspd -XO- 0]

all I know is this... when training on the rifle in real time, we were told that the round travels, in a wave sort of motion, very slight but still a wave. The bullet drops and raises, but each time it raises it is just a little lower than the prior. When striking at a 50m IRL you aim center of mass on the target, at 100m you aim a little lower, 150m is when you start heading back up for the center of mass aiming just a little up from where you did the 100m target. at 200 meters you are a little higher, 250m you are just under center of mass, and then finally at 300 you are center of mass of the target. Beyond 300 your round starts to loose its momentum and thus you have to aim a bit higher than usual. I only qualified to 300m but I'm guessing a marine qualifying at 500 would agree with me.

i think what you talk about is not only about ballistic now, but also how your rifle is zeroed

No. Weapons zeroing is so you can get a proper sight picture and so that your eyes aren't fooled sorta speak. The way I described the aiming vs the targets also has nothing to do with wind... if the bullets were properly simulated this would be the case. Here is my proof.

Here are adjustments for wind.

I'm done arguing over this now... I just feel its safe to say that the bullet trajectory is NOT properly simulated, if it were then the rifling wave would be simulated.

[4 IN 1 0]

its more to due with how the sights is modeled and thats another thing, also there is no wind which affected the gaddamn ballistic

edit: besides no one said that the ballistic model is 100% accrate

@Eihort

you have a point, but i fail to see that this point could prove anything aside for the fact of a difference between a $1500 training soft and a game

[frederf 0]

This argument that ArmA is half-assed just to not dip into VBS2 sales is the most rubbish piece of nonsense that needs to die now.

Grenades made of rubber and bullets that don't slow down in air are not to prevent the USMC from using ArmA as their trainer. The US military as well as other militaries don't violate software license laws just to save a few bucks. If you had ArmA so good that it was VBS2 about, you could just have a commercial/military version, charge $1500 for a seat with all the extra goodies and support, and the real clients would pay for it.

[UNN 0]

How accurate should OFP and Arma be? It was sold to the gaming community long before the military took interest. Being a game it has to run on the lowest possible spec if it wants to appeal to as many people as possible. So don't be surprised if it does not simulate the damage an Ak would make if a bullet shot straight up, hit you on the head on it's return journey. Everyone here does not buy Arma to train for combat, they buy it to play as a game.

Quote[/b] ]Looks like a parabola to me... which is wrong.

Quote[/b] ]yes because air friction is not implemented.

What else?

As for how Arma models trajectories compared to parabolas:

In this example (one of many I have for OFP and Arma) the red line represents a parabola designed to reach a specific distance. The yellow line represents a trajectory taken straight from Arma , output via Arma.rpt and exported directly to excel. Notice the marked difference in angle of elevation to reach the same distance.

Here are some samples of Arma trajectories for the M119:

The purple plot is at an elevation of roughly 25 degrees, notice how it gives the longest range. The blue plot is around 45 degrees. If this was based on a parabola, then a 45 degree elevation should provide the greatest range.

Now I was never interested in anything other than Artillery. But is there any reason to assume artillery is not treated to the same sort of maths as a rifle bullet?

I could go on to discuss all the other problems I see when dealing with trajectories in games, that try to be as close as possible to real life, but I doubt it's worth the effort.

[rundll.exe 12]

Your plots make me believe there IS something like air friction, as the bullet has allmost zero horizontal speed at the end.

Interesting to see, gives me a better picture how to hide for artillery (and shellers in CTIs)

[frederf 0]

Your plots make me believe there IS something like air friction, as the bullet has allmost zero horizontal speed at the end.

Interesting to see, gives me a better picture how to hide for artillery (and shellers in CTIs)

Those are some really surprising charts.

Can you provide a chart of linear speed of the projectile vs time?

[Törni 0]

Wind, target vector+speed make all the difference in aiming. Plus the fact that pistol rounds should lose their power and accuracy more rapidly over longer distances.

[UNN 0]

Quote[/b] ]Interesting to see, gives me a better picture how to hide for artillery  (and shellers in CTIs)

I should have pointed out that the M119 I was using has a modified time to live for the shell. The default Arma value is 20 seconds, so the unmodified M119 will be restricted to something similar to the brown plot, but even then it's effective range is reduced to 2500m. I've never tried it with COC, but the above graph is probably close to it's flight paths, as it uses an extended time of life.

Quote[/b] ]Can you provide a chart of linear speed of the projectile vs time?

Do you mean the distance it travels horizontally over time or the actual speed of the shell over time?

I did take a quick look at the speed of the shell over time, which did yield some interesting results. The main one, which may be the cause of this thread is the speed command.

If you use that command to grab the shells speed during flight, it will return a constant value (it's initial muzzle velocity). But that looks like it's a limitation of the command itself. As an alternative indicator, I tried using the velocity command, measuring the difference in X,Z vectors over each time slice, to calculate the speed of the shell. That did not return a constant value like the speed command. However it did not return the values I expected either.

You also have to take into consideration the limits of my test. Like I said, I ignored the Y vector of the velocity command when calculating speed. Even though the shell was fired in a straight line, the Y vector does fluctuate, probably due to dispersion and recoil e.t.c I also conducted these test in real time, so my method of capturing the data could introduce minor errors. Finally I don't really trust my maths.

For me the important aspects of Artillery I want with regards to projectiles are Flight path and Time of Flight. I'm pretty sure the game does not take the velocity into acount when calculating damage on impact for class CannonCore. It may take the type of terrain\object the round impacts with into account, but thats hard to say for sure.

I could bang on all day about this sort of stuff, if I had the time. I've transferred ballistic equations into OFP for my Forward Observer & Mortar addons. I managed to match the ballistic equations with OFP's equations (within limits) so I was happy with that. But it did highlight some major hurdles for anyone who wants to implement such things into a game. The more complex and realistic the ballistics model becomes, that longer it takes to calculate where to shoot for the AI. We as humans use trial and error to become marksmen, the same way COC's UA used Neural Networks for it's artillery.  But Arma can't do that, if it had to use pure maths for every bullet fired by every AI in game, the whole thing would probably grind to a halt. So some compromise has to be found.

I have spent a few months trying to come up with an abstract ballistics model for the likes of the M119, something that allows me to produce similar trajectories to Arma's without spending minutes calculating the angle of elevation to fire e.t.c. So far I've had no luck. For me I narrowed it down to three important aspects given the fact that I know the range and different in target elevation; Angle of elevation, the peak height of the trajectory and the time of flight.

So perhaps you sould be doing the same thing for bullets? Given that in Arma, bullets only last for three seconds max. what are the important factors to model during that time period while still keeping the game playable?

Anyway enough of my waffle. I don't mind knocking up simple graphs for the M119, showing the distance a round travels horizontally over time, but thats about it.

I'm just not that interested in pulling apart every aspect of Arma's projectiles. So if anyone wants the configs, test mission and instructions on how to get the data into excel. Then let me know.

[eihort 0]

This argument that ArmA is half-assed just to not dip into VBS2 sales is the most rubbish piece of nonsense that needs to die now.

Grenades made of rubber and bullets that don't slow down in air are not to prevent the USMC from using ArmA as their trainer. The US military as well as other militaries don't violate software license laws just to save a few bucks. If you had ArmA so good that it was VBS2 about, you could just have a commercial/military version, charge $1500 for a seat with all the extra goodies and support, and the real clients would pay for it.

Then why didn't they do that? What's your theory?

[DaveG 0]

Quote[/b] ]Then why didn't they do that? What's your theory?

They did. Look at the graphs on the previous page. I'd say it's fairly conclusive that air-resistance is simulated.

[eihort 0]

I meant in all the other aspects that VBS2 has over Arma like the tracers and things.

[kronzky 5]

I have added some ballistics information to my target range script, but since I'm not a weapons specialist it's hard for me to judge if the data created is correct or realistic.

For example, here is a chart created from data generated with that script:

(Does a bullet from an M9, fired straight, really just fly roughly 200 meters?):

The odd distance steps are there because of the limited sampling capability, due to the speed of the bullets and the speed of the script.

Perhaps somebody with better access to real-life ballistics charts can check whether the data generated makes any sense...

[max power 21]

The ballistics in ArmA are in poor shape compared to what? They aren't perfectly real, but I don't think they are terrible.

[Donnervogel 0]

Perhaps somebody with better access to real-life ballistics charts can check whether the data generated makes any sense...

well I'm in no way a weapons specialist but I was doing a script that would calculate how the tank main gun has to aim to hit a specific target and my findings are, that at least tank ammo behaves closely to a standard trajectory parabola. They also add drag to it during flight. With this I have been able to get really good results. So I think the projectiles behave pretty "plausible" but that does not mean realistic Obviously real projectiles have different flight and drag characteristics that would be hard to find out for a game developer. I just think they have a good approximation to a realistic flight path depending on the parameters they can work with (drag coefficent, initial speed, ...) But if they chose the right parameters is another question

And well. I never tested it with small arms so this is just valid for the m1a1 main gun atm

[kronzky 5]

Yeah, from what the data I've been comparing so far the ballistics seem to be pretty close to reality.

I was at first surprised how long it would take a bullet to travel a kilometer, for example. But then I did some measuring via my program, compared it to real-life data, and it was pretty darn close.

Also, the myth that ArmA bullets all travel at the same speed can definitely be proven wrong if you look at the actual measurements.

As far as trajectories are concerned - I haven't really found a good source for real-life data yet, so I can't really speak for that (But I also have to admit that I haven't really looked too hard, assuming that there would be lots of people here that have all those at their fingertips already.)

[max power 21]

Yeah, from what the data I've been comparing so far the ballistics seem to be pretty close to reality.

I was at first surprised how long it would take a bullet to travel a kilometer, for example. But then I did some measuring via my program, compared it to real-life data, and it was pretty darn close.

Also, the myth that ArmA bullets all travel at the same speed can definitely be proven wrong if you look at the actual measurements.

As far as trajectories are concerned - I haven't really found a good source for real-life data yet, so I can't really speak for that (But I also have to admit that I haven't really looked too hard, assuming that there would be lots of people here that have all those at their fingertips already.)

The problem is that in real life, the amount of drag acting on the bullet depends on its speed. I'd imagine that ArmA has a constant, averaged amount amount of drag acting on the bullet throughout its flight.

[Second 0]

Here's some data from http://www.ammo-oracle.com/body.htm

following M855's (5.56) line and it seems that ArmA has it pretty much same trajectory. At 550 meters my rough calculations (converting inches to centimeters with not very precise values) tells pretty much same drop, i ended up to about 130 cm.

At 300 meters... Seems to be pretty much same also. I don't see reason to tweak these values: I wouldn't notice any difference or wouldn't care.

[Heavy Metal 0]

Kronzy's graph shows a 440M zero for the M4A1.

That thing should have a 200M zero.

[Donnervogel 0]

I don't think it has to do with drag being calculated as a constant but with the rounds not having the real parameters (drag parameter mainly). From my testing it appears that drag is correctly calculated but I have no idea if the drag parameters are realistic.

[Iron+Cross 0]

What was being talked about was not just bullets but things like RPG's, have any of you tried to make an RPG ark properly?

also 9mm rounds keep the super sonic crack at over 1 kilomiter!! & a 9mm shouldent do that under a 10 degree ark! & im no expert but i dident think 9mm's could reach more than 200-400m max??

try placing a guy 500-1000m away from you & do the switch player gag to see that a 9mm & a 5.56 will kill the same at that range & still have crack!

[kronzky 5]

Kronzy's graph shows a 440M zero for the M4A1.

That thing should have a 200M zero.

Actually, the M4A1 (and most other guns) are zeroed in at 300m in ArmA, which matches perfectly with the data in my chart. (I'm not quite sure where you are seeing the 440 meters you mention.)

What was being talked about was not just bullets but things like RPG's, have any of you tried to make an RPG ark properly?

That is tricky because of the unique arcs those RPGs have:

Again, I wasn't very successful in finding official ballistics charts, but the general principle of their ballistics and the range looks realistic (except that it seems to self-destruct about 100m too early, but that should be pretty irrelevant for game play);

[fasad 1]

Nice work Kronzky, fantastic graphs!

I'm especially interested in the high time-to-live and natural trajectory of the artillery shells. Very promising

[4 IN 1 0]

Kronzy's graph shows a 440M zero for the M4A1.

That thing should have a 200M zero.

is trajectory related to zeroing a rifle?

[max power 21]

Kronzy's graph shows a 440M zero for the M4A1.

That thing should have a 200M zero.

is trajectory related to zeroing a rifle?

It is the reason why rifles must be zeroed.

[whisper 0]

Also, the myth that ArmA bullets all travel at the same speed can definitely be proven wrong if you look at the actual measurements.

Errr...

Just to be sure : for me, the "myth" (that I found out to be true) is that ArmA bullets do not decelerate during their flight, ie their speed is constant.

Is that false? Because when I monitor a bullet's speed using a loop, I don't see the speed change. I maybe wrong, but I don't think friction is taken into account