How do video game bullets and projectiles work?

[El_Vikingo]

No wonder the ******** never went down! I have to rethink my whole strategy when shooting at range.

[Rico11b]

Paladin-X explained it pretty well, but I'll also note that DICE used basic high school physics equations throughout the game.

While playing around with the mortar the other day in the editor I could do some simple math and calculate at what distance the round was going to land. Was kinda cool.

Only oddity you have to account for is that DICE used 14.8 m/s*s as gravity in-game, instead of the 9.8 m/s*s in real life. Not sure why they did that tbh.

Probably because their scale is off in game. One meter in game is not the same as a real life meter. It's more like 1.5 or 2 meters. Maybe they uped the gravity to get more bullet drop to "seem" more real and a little less acade like. I think they didn't do their homework.

[El_Vikingo]

They weren't creating a simulator though, so arbitary units are just as good.

[Rico11b]

They weren't creating a simulator though, so arbitary units are just as good.

So why even bother with using realistic weapons at all then. Why bother using anything that simulates reality. You mentioned "arbitrary units", I would say you are correct. (start of sarcasm) I'm sure they were thinking, "lets make all the in game player models 6 ft 8 inches tall (2 meters) and see how long it takes for gamers to discover that we don't know jack about anything remotely realistic". (end of sarcasm) IMO I don't think they knew what they were creating. They just threw a bunch of **** together and left mod makers to figure it all out as best they can.

My hat's off to you DEVELOPERS. You have taken a shit game engine and made it into a wonderful bowl of ice cream Bravo, Bravo! If it weren't for you guys most of us would have tossed BF2 into the trash for good. Thanks for making the 50 bucks I spent on BF2 worth something after all.

R

[MrDow123]

Ummm sorry if I sound rude, but BF2 was a damn fun game. Even if it was unrealistic, Vanilla is still a fantastic game. I think PR is even more fantastic, but BF2 by itself is an awesome game.

Maybe I just dont care as much to realistics as you guys do, but I think vBF2 is still an excellent game. PR IS better though

[geogob]

Sure could. This is initially what I wanted to do but it's questionable as to whether or not the effects on gameplay would justify the huge amount of work involved, calculating exactly how much to lower the sights would be incredibly hard and we would have to edit every single weapon in the game to move its sights down like that....

EDIT: wait. Let me reread the whole thread... I think I missed something about your reply, Jaymz.

EDIT 2: Ah! Get it now... missed the single post that held the key.
As I understand it, you were suggested to use artificial means to simulate zeroing whilst using still improper ballistic models (what ever the reasons to that - possibly engine limitations).
To that, I say no, that's not worth it nor a good idea or a good time investment. I'd rather focus on finding a way to implement a realistic model. Now to the original post (which is still valid, but I original thought you were questioning the pertinence of using a realistic model - which wasn't the case, my bad for the misunderstanding).

I do think it would. In my experience with infiltration, the differences in type of bullet having different flight characteristics and difference with rifles having different muzzle velocities really come to play when you have proper external ballistic models.

Quite a few experiments we made showed that the impact is considerable. I experimented a lot with zeroing in game using different types of rifles and different zeroing ranges.

I can assure you that having a rifle zeroed at 500 yards would have an important impact on it's use at close range. Same with a rifle zeroed at 50 yards when used on targets at 500 yards. With slower projectiles, the effect grows even further.

In a game like Insurgency, I can even accept the fact that they use direct line tests for shots because of the short range engagements (let alone mention the pointlessness of doing all this work for that game). In Infiltration, I noted major gameplay impact from the use of somewhat more accurate ballistics models (although not exactly true to life). Most engagement occur at ranges under 250 yards in that mod.

In PR, having engagements at over 500 yards is not unusual. My experience tells me that at these ranges, it will have a considerable impact (one of them being people whining - "BS I can't hit ****").

[Blaec]

so if a bullet is an actual projectile in the game does this make it possible to shoot bullets out of the air with another bullet?
my god that would be so useless yet so cool

[Long Bow]

I'm still trying to wrap my head around the BF2 bullet physics.

But what I still don't understand is how the bullet drop becomes so pronounced at long range. If we take the linear bullet drop zerod in at 600m, the degree of drop from the barrel out to 600m would have to be slight, say 1 degree. Assuming that is the case and the bullet hits the 600m mark and keeps traveling, in game it seems to start droping more, more then a 1 degree drop.

I don't understand how it appears to drop more at range then in between the zerod range and the barrel? Does the speed or momentum of the bullet come into play? Example being the bullet drops 1m every second, traveling at top speed out to 600m and then begins to slow down. The 1m drop per second would still be in effect but since the bullet speed is reduced the drop is more pronounced.

Is bullet speed variable in game? I'm sorry I'm not trying to be argumentative I just don't get it?

[Rico11b]

Okay, just so I understand this right:

Rifle M16 A is ranged in at 600m
The muzzle velocity is something like 975m/s if I remember correclty, so let's round it to 1000 m/s so it's easier math-wise.

The bullet needs 0.6 seconds (in game, as I doubt the velocity gets recalculated in flight) until it reached 600m. That means it droped somewhere around 2,6m using the 14.8m/s² gravity value.

The same Rifle at 300m -> Bullet droped 0,67m


To hit someone at 300m with a rifle zeroed in at 600 I'd have to aim almost 2 meters below the point I want to hit (i.e. below the feet for a headshot) - I am 100% sure that is not the case in Project Reality.


I used d=0.5*g*t² as formula for calculations, but I am not 100% sure I did it right (tired ) (g=gravity t=time)


-----

So, to re-iterate

Are you 100% comepletly and utterly sure the bullet drop starts as the bullet leaves the rifle for small arms and not only as soon as the projectiled reached the "zeroed at" mark?

975m/s (3200 ft/s) is not used anymore. That was for the old M193 55 grain bullet. NATO now (since about 1996) uses the M855 62 grain ball ammo. Which has a listed muzzle velocity of 930m/s(3025 ft/s). That's what PR should be using for muzzle velocities on the M16 variants. If they aren't then they are using old out of date material.
Bullet drop at 600m (656 yard) should be somewhere in the neighborhood of 78 inches down, instead of the 2.6M (102 inches) you referred to in your example. All in all it means that the Gravity settings in game are WAY over powering, and are in desperate need of adjustment.

R

[BlakeJr]

So why even bother with using realistic weapons at all then. Why bother using anything that simulates reality. You mentioned "arbitrary units", I would say you are correct. (start of sarcasm) I'm sure they were thinking, "lets make all the in game player models 6 ft 8 inches tall (2 meters) and see how long it takes for gamers to discover that we don't know jack about anything remotely realistic". (end of sarcasm) IMO I don't think they knew what they were creating. They just threw a bunch of **** together and left mod makers to figure it all out as best they can.

My hat's off to you DEVELOPERS. You have taken a shit game engine and made it into a wonderful bowl of ice cream Bravo, Bravo! If it weren't for you guys most of us would have tossed BF2 into the trash for good. Thanks for making the 50 bucks I spent on BF2 worth something after all.

R

Vikingo was actually talking about DICE, NOT about the PR team...

[Rico11b]

Vikingo was actually talking about DICE, NOT about the PR team...

Yeah I knew that, I was talking about DICE as well. In the first paragraph. In the second paragraph I was giving an ataboy to the PR Devs for picking up the ball where DICE dropped it DICE didn't drop the ball, they fumbled it lol

R

[Alex6714]

Something I have been thinking about for a while: Bear with me here.

If in BF2 you can have a projectile speed and with that the "time" it takes to get to its target, what is the point of hitboxes that move to simulate the need to lead your shot? As I see it, if the bullet takes 0.6 seconds or whatever to reach the target, then you have to aim 0.6 seconds ahead, where the target will be in 0.6 seconds. So why have hitboxes compensating for this aswell? Or is it just weird lag? Or am I just out of my mind? Why not have them fixed to the target like real life when it is the bullet travel time that we are compensating for, as I understand this can be simulated ingame?

I hope someone understood that and corrects me. I am just curious and I don´t know that much about the physics of BF2.