Bullet Drops

[RHYS4190]

Originally Posted by TheLean

In real life a rifle is set (zeroed) to hit exactly at the crosshair at a certain distance, which is usually around 2-300 meters for assault rifles. Zeroed in means that the bullet should hit exactly where we are aiming the crosshair at that certain range. The bullets IRL actually travels above the crosshair when at 100 meters and dead on when at the zeroed range. When the bullet starts to drop it drops in a non-linear trajectory. For example that if the rifle is zeroed at 200 meters the bullet will hit 10 centimeters above the crosshair at 100 meters, exactly at the crosshair at 200 meters, 20 centimeters below at 300 meters and then 50 centimeters below the crosshair at 400 meters. These figures are fictous and exaggerated but you get the idea.



Look at the graph in this example to get an idea of what im talking about. You can also see that the bullet starts below the scope (obviously). In real close ranges the bullets hit a bit below the crosshair. Also notes that the bullets drop more rapidly at longer ranges.



The PR bullets seems to fly straight to a certain point and then start to drop in a linear pattern, meaning for example 10 centimeters below the crosshair for every extra 100 meters. But this is just guesses. Any developer or coder who knows for sure are welcome to tell us how it really works in PR.

I think your on to some thing here, with the bullet drop. but your exaggerating a bit.

you stuffed up your English, 1 centimetre is roughly about the width of your little finger, So yeah if we where shotting ping pong balls at each other then there would be a bullet drop of about 10 cm.

What you are looking at is a bullet drop of a few millimetres. Not 10cm lol.

If you where aiming 10cm above your target you’d practically be firing into bloody orbit and be more liable to hit the sodding international space station. lol

But yeah cool idea though i think it has a lot of merit. il definitely give it a go.

[puppezed]

Originally Posted by RHYS4190

I think your on to some thing here, with the bullet drop. but your exaggerating a bit.

you stuffed up your English, 1 centimetre is roughly about the width of your little finger, So yeah if we where shotting ping pong balls at each other then there would be a bullet drop of about 10 cm.

What you are looking at is a bullet drop of a few millimetres. Not 10cm lol.

If you where aiming 10cm above your target you’d practically be firing into bloody orbit and be more liable to hit the sodding international space station. lol

Either I misunderstood what you wrote or you are mixing up length units and angle units.

Let´s take for example the flight path of an 7.62x39 AK round from Lapua and presume the gun is zeroed to 150m. The flight path is:
50m : +3.2 cm
100m: +4.8 cm
150m: 0 cm
200m: -9.0cm
300m: -64.3cm
http://www.lapua.com/fileadmin/user_...ridges2009.pdf
So if you are shooting at ranges of 300m the drop is 64.3cm and you have to aim that much above the target in order to hit it dead on.

With a mildot sniper scope, milradian angle unit comes into play. 64,3cm@300m equals 2.2 milradians. Since the angle between dots in a mildot reticle is 1 milradian, using the second dot under the cross section of the scope would mean a hold over of 2 milradians which equals 60cm@300m which is pretty close the required 64.3cm hold over. 1 milradian angle equals the length of 10cm@100m and 30cm@300m.


I can tell by first hand experience that hitting a man sized target with an AK (well, at least with a Finnish AK) is quite easy but you do have to take bullet drop into account either by aiming above the target or by manually adjusting sights.

I´d like to see Project Reality putting more emphasis to ballistic flight paths of all projectiles (bullets, RPGs, cannon round etc). In my opinion Red Orchestra (previously WW2 Unreal Tournament mod, now a stand alone game) has implemented ballistic flight paths pretty well and the bullets really do drop. It makes hitting targets more challenging but much more realistic and rewarding.

[McBumLuv]

Originally Posted by puppezed

I´d like to see Project Reality putting more emphasis to ballistic flight paths of all projectiles (bullets, RPGs, cannon round etc). In my opinion Red Orchestra (previously WW2 Unreal Tournament mod, now a stand alone game) has implemented ballistic flight paths pretty well and the bullets really do drop. It makes hitting targets more challenging but much more realistic and rewarding.

My thoughts exactly

However, as far as I can see, the only perceptible problem keeping ballistics from being implemented into previous version is that there's an unfortunate bug with the BF2 engine where tracer rounds will actually drop at a much greater rate (because of either reduced speed or increased drag, I cannot remember which though). Interestingly, it only happens if the tracer rounds are one in every x number of bullets, the tracer bug doesn't come into effect if all rounds are tracers or none are.

That's the only obvious problem with the being implemented, AFAIK, but if any Dev can correct me the extra information would be greatly appreciated.

In any case, Combined Arms has implemented ballistics (I believe it was Zangoo finishing his project, as well), and they work well, the only difference otherwise is that all rounds are tracers, though the tracers are slightly smaller. And seeing as many things from CA are beeing ported over straight into PR, it might increase the chances of finally seeing ballistics inPR on the bf2 engine.

ATM the only mod that accurately recreates them is the WoOkIe sniper mod

[MrScruff]

The guys with the graph just reminded me of a great little tool I used before on another game. It was also based on reality but set in WW2. Using planes, tanks, trucks, transport planes, bombers, etc etc etc. The game however was even MORE realistic. Each squad would be given a mission, and that could be to transport troops to the front, drop bombs, move a supply convoy to the front. Everything done in real life was put in that game. Even changing gears in tanks and trucks. Even starting the engine. Opening the hatch.

ANYWAYS, the point Im getting at is the marksman rifles and snipers in that game had this sweet function whereby you can zero in your target by adjusting the sight according to the distance. If the target is 245m away you would be able to put a setting on that general distance i.e. 200m or 250m. The game allowed you to adjust your sights by selecting the same weapon slot. In BF2 and PR selecting the same weapon slot merely changes fire modes. However if we want to aim at "reality" then get this suggestion:

Sniper rifles vary on some maps. Small maps i.e. Insurgency 2km map get the M24, which in PR has a less powerful scope than the sniper rifles on those 4km maps i.e. Kashan Desert and Quinling. Since the sniper rifles don't have a fire mode selection why not implement a sight adjustment module. And each time you select the same weapon slot to change distance settings it will loop around these options, 100, 200, 300, 400, 500, 600, 700, etc etc. The reason why I mentioned the 2 different sniper rifles that PR accommodates is because I only really see this module useful on 4km maps.

[McBumLuv]

Originally Posted by MrScruff

-snipped stuff about zeroing methods-

Well, that's possible with the BF2 engine, but we don't need o go to lengths of creating different weapon slots. The WoOkIe sniper mod uses the command screen to elavate the scope to different Mil settings. IIRC, I'm pretty sure it was created by Mosquill (an ex-pr dev), whose's also made a similar system for BF2142.

For TR (the mod for bf2142), he used the Q-rose rather than the command screen to set elavation, however. I'm really not sure if using the Q-rose in the same manner is possible with the BF2 engine, however close they may be. But I would think there should be a fairly good chance of that also being possible, which would be awesome.

Anyways, I'm not sure if it would be possible to have a different command/squad screen based per kit, but if the Q-rose idea isn't possible but that is, well we know using the squad screen to set elavation is possible with the BF2 engine

Anyways, to get a feeling for ballistics and the BF2 engine, I'd highly suggest that anyone interested also take a look at the sniper mod, which'll have an event coming up in a few days anyways.

http://www.realitymod.com/forum/f376...-new-post.html

[Tannhauser]

Originally Posted by McLuv

And seeing as many things from CA are beeing ported over straight into PR, it might increase the chances of finally seeing ballistics inPR on the bf2 engine.

Really!?
That's sweet! I hope DEVs will do that for ballistics, it'll stop players from going ''BUT I HAD A SHOT ON HIM! WTF did I miss!?!11!11''

[TheLean]

Originally Posted by puppezed

Either I misunderstood what you wrote or you are mixing up length units and angle units.

Let´s take for example the flight path of an 7.62x39 AK round from Lapua and presume the gun is zeroed to 150m. The flight path is:
50m : +3.2 cm
100m: +4.8 cm
150m: 0 cm
200m: -9.0cm
300m: -64.3cm
http://www.lapua.com/fileadmin/user_...ridges2009.pdf
So if you are shooting at ranges of 300m the drop is 64.3cm and you have to aim that much above the target in order to hit it dead on.

Yes, this was exactly what I was trying to say. I read my text again and it makes sense to me, but I guess it is my explaining or english that is confusing.

[privetB]

Originally Posted by flem615

I think he means machine pistol. Aka submachine guns. Correct me if I'm wrong

yeah. I am sorry, I forget that it is sub machine gun ^^. In germany those kind of weapons are called Maschinenpistole, which means machine pistol(as you said).

[McBumLuv]

Originally Posted by Tannhauser

Really!?
That's sweet! I hope DEVs will do that for ballistics, it'll stop players from going ''BUT I HAD A SHOT ON HIM! WTF did I miss!?!11!11''

I dunno, it's up to the devs, but seeing as sounds/hydra deviation and stuff got into 0.86 and were done by the CA team, I'm hoping ballistics will get in as well for 0.9, with a large deviation reduction of course

[Jonny]

Originally Posted by TheLean

The PR bullets seems to fly straight to a certain point and then start to drop in a linear pattern, meaning for example 10 centimeters below the crosshair for every extra 100 meters. But this is just guesses. Any developer or coder who knows for sure are welcome to tell us how it really works in PR.

Wrong.

They follow a parabolic trajectory whose starting velocity is parallel to the barrel of the rifle (discounting deviation). It is NOT a 'linear' drop.





I have attempted to add realistic ballistics into PR, along with help from Nedlands, CAS-117, Mosquill and Zangoo. We discovered that the tracer rounds start at a different velocity to the non tracer rounds, and that it is too much of a difference to be acceptable. The difference is so great that either one of the realistic gravity or quadratic viscous drag force make the tracers follow a noticably different trajectory to the non tracer rounds.

The DEVs do not approve of any of the workarounds that have been found to this day, and zeroing only some of the guns is not acceptable, apparently.




Some of the work we did went into the wookie sniper mod, if you want to see some decent ballistics.