Realistic ballistics & zeroing rifles

[Jonny]

The ballistics in PR are currently non-existant.

In the guide I see claims of rifles being zeroed, but in the files I see values for gravity modifiers set WAY too low. Some of the values are 0.3 and 0.1, there is no way in hell you can EVER claim this is realistic because the lowest values acceptable are about 0.67, which would give a value close to gravity on earth. If you then try to approximate drag this value should be higher to compensate, not lower.

So the current 'ballistics' are basically taking the piss. I have re-done them from scratch, including drag in my model.

The equations for the velocities and displacements of the bullets can actually be found on wikipedia. I have used the same equations, and actual values of bullet masses, diameters and the loss of velocity at 300m of a certain kind of bullet to get all of them to act more realistically.

This means, that with my model:

• heavier bulets travel further than lighter bullets
• drag exists
• wider bullets feel more drag than thinner bullets
• all bullets follow realistic and believable ballistic tragectories
• all rifles can be zeroed to any distance they can be fired to
• sniper rifles can be zeroed to several different ranges

To zero a rifle the user must be made to aim the barrel slightly above the target, to let the bullet rise and then fall onto it at the range it is zeroed to. To accomplish this the sights must be moved down by a few tenths/hundredths of a degree so that when they are lined up on a target the rifle will be zeroed correctly. This angle is very small, it only causes a rise of 10-20 cm at the highest point, but you will be able to say that the rifles are actually zeroed and that the ballistics are realistic. I was also told by a friend who was in (I think) the army cadets that they are told to aim for the neck, not the head. I think this shows why that is.


The current model used is a parabolic tragectory (red line), which follows a totally different path to a ballistic tragectory (blue line):
This particular graph shows the L85 projectile with and without drag fired at the same angle with the same mass and the same velocity. With drag it reaches 600m, without it reaches over 1000.
graph

DEVS:
To add this model to the mod you must set ALL gravity modifiers to 0.666 (9.81/14.73), ALL weapons MUST have a drag modifer of 1 in the same section as the tracers, Masses must be set to the values listed in the tables page of the spreadsheet I have PMed to dbzao, and the velocities must be set to the values shown on the table (which I believe are the correct values, they can be changed without affecting the mass except the L85, which is used to calibrate everything else).

The new masses given are almost all less than 1 kg, which is the default mass for projectiles I think, so will only help stop bodies flying around.

I still need some data for UGLs and all tank rounds used in the game.

The tables also contain data for recoil and damage (kinetic and explosive) which dbzao has already asked for.

[Mora]

interesting..

[H3eadshot]

Nice work, interesting to see how this pans out.

[Waaah_Wah]

lol, why isnt Jonny a R-DEV yet?:P

[VipersGhost]

IIRC the gravity level is set like that as to compensate for the BF2 meter being longer than a RL meter. I'm not saying its still correct as it is but I'm pretty sure why it's like that.

[Jonny]

Originally Posted by VipersGhost

IIRC the gravity level is set like that as to compensate for the BF2 meter being longer than a RL meter. I'm not saying its still correct as it is but I'm pretty sure why it's like that.

The BF2 metre is EXACTLY the same as a RL metre.

http://www.realitymod.com/forum/bf2-...8.html?t=30068

The scales are out by different amounts for everything else. Its like that because no one has tried doing the ballistics properly until now.

[Raymond.Reiloff]

1 RL m might be 1 BF2 m but i doubt the gravity is RL based, tho im not sure

[zangoo]

i cannot wait till this is in the game, it will add so much to game play. i am really interested to see how this will change fire fights.

[VipersGhost]

Originally Posted by Jonny

The BF2 metre is EXACTLY the same as a RL metre.

http://www.realitymod.com/forum/bf2-...8.html?t=30068

The scales are out by different amounts for everything else. Its like that because no one has tried doing the ballistics properly until now.

Ah OK, good to know. For some reason I swore I had heard it elsewhere. Well heck ya then, lets get this fixed. I'm all for fixing the ballistics big time! As much as we can at least.

[Jonny]

Originally Posted by Raymond.Reiloff

1 RL m might be 1 BF2 m but i doubt the gravity is RL based, tho im not sure

No, in BF2 the default is 14.73, according to Rhino.

Hence the need to set the modifier to 0.666

this gives a value of 9.81 to 3 sf, which is exactly what we need it to be.

(just read the line under "DEVS:")

The gameplay wont be changed that much, but it will be harder for snipers to hit targets properly at long ranges. It will be a lot more difficult to guess the time it takes the round to reach the target.