Armed Assault weapon ballistics

[Iron+Cross 0]

Ahh so i think i understand now, you werent just ignoring me & being a bunch of ignorant smeg heads bitching about somthing that you cant do yourselvs i was just off topic?.....(or were you?)  hehe.

well im trying to figure out do you guys mean that you want the projectiles to react to the Wind simulated in game?

So would it not be possible to tap into the, (simulation="shotShell" command in ammo config so that it interacts with the wind like the flags & smoke do? (asking some one who knows about code.

Now when i was playing with ICP's RPGs

they use a way more curved trajectory than the ones in arma that seem to travel realy flat like a bullet almost..

am i wrong or what? (personally i never noticed the diff untill you chaps pointed it out.. & ive been playing since OFP 01)

I got one question is the Supersonic crack activated by the real speed of sound or is it at some engine set speed? if so what is it? as it could be quite slow..??

supersonicCrackNear[]={"\ca\Weapons\Data\Sound\supersonic_crack_close.wss",1,1};

Now another thing do i understand you chaps correctly/wrongly when i say we cant have the curved trajectory's that we had in OFP like with the ICP RPG's?

do ammo configs sutch as:

thrust=000; (how much push will be behind it)

thrustTime=0.00000; (how long the projectle will have thrust)

&

timeToLive=4; (for deleting the bullet/tracer)

maxSpeed=241; (max speed projectile will reach)

not have ANY effect on the trajectory of the projectile now at all?

[maddogx 13]

I don't know where you guys got the idea that bullets don't have a ballistic trajectory.

Any cheap bullet cam script will prove that they do.

[max power 21]

I don't know where you guys got the idea that bullets don't have a ballistic trajectory.

Any cheap bullet cam script will prove that they do.

I think they were talking about a ballistic coefficient to help match up the flight of the bullet to the arc actual bullets follow (instead of behaving as if they are flying through a vaccuum)... at leat I hope so!

[frederf 0]

Do bullets slow down in arma after being fired?

[Iron+Cross 0]

well if some one could point me to a bullet cam script with a small info bar on speed etc. i could tell yeh...

[whisper 0]

Do bullets slow down in arma after being fired?

No, and that's the only point I seee wrong in ArmA ballistic. But I'm no expert, so I keep asking : have some1 a list of what is needed for proper ballistic in ArmA?

We have

- correct air friction effect for bullets. Currently not implemented.

And?

Nota : I don't mean by that that with such a tiny list, everything is right and BI has nothing to do. If correct air friction effect is doable without too much CPU impact on large scale fights, then by all means, BI, do it!

But, if it's the only element missing, then ArmA is not THAT bad in the ballistic department, is it?

[TheElite 0]

is it not the case that ,in arma physics world , everyting with mass

as an affect when multiply by speed.?

maybe when original arma came out we saw that bullet sometime make man shoot flying in air , which may support this theory ?

also this problem when buidling ,altho static has great mass and when tank hit at speed , tank will fly and land on sun ( fixed in 1.05 ?). but wrecks of jeep not fixed when tank ram it.

maybe Bis work on bullet now like they fixed tank v building and in 1.06 is fixed or 1.07

also bullet is not small projectile any more but real big tracer ,maybe they applied mas wrong and they will fix / unless tracer is only a droped particle source ?

anyway there cant be much wrong because arma physics is best i ever saw , right down to how wind affect a leaf is amazing.

[Iron+Cross 0]

So keeping in mind i never was a mastermind, did flashpoint projectiles slow down? like the custom RPG's? is that what made the ark in flight path?

(if so is that what is stoping the 9mm from arking properly?)

on second thought it did dident it? because i remember the pistols not having great range.. it was like a paintball marker without a flatline barrel or an APEX barrel.

[max power 21]

So keeping in mind i never was a mastermind, did flashpoint projectiles slow down? like the custom RPG's? is that what made the ark in flight path?

(if so is that what is stoping the 9mm from arking properly?)

No, they didn't slow down. They arced because of a simulation for the force of gravity. Also remember that mass and other properties of an object don't affect the rate at which they accellerate due to forces.

Is it a sure thing that 9mm bullets didn't arc in arma, or is it perhaps the way that the weapons were zeroed?

[whisper 0]

RPG did slow down (and should also in ArmA), AFAIK, because their simulation took the sideAirFriction parameter into account.

Bullet simulation, though, do not take this parameter into account

[fireship4 0]

I've just pasted in the airfriction part from the config of the missles into the M249. It works.

In fact, If you set the bullets to be travelling slow enough with initspeed...

(don't forget out of cfgweapons, cfgmagazines and cfgammo, if you put different values for the same thing in each one - for example initspeed - then they will override each other in a particular order i think. For example if you set initspeed to 900 in the m249 in cfgweapons and then set the m249 magazine in cfgmagazines to have 10 as initspeed, the latter will work)

...and you add in air friction, the bullets actually turn around in mid air and head back to their origin! This shows something important - airfriction is based on the direction the bullet was fired in the first place. the force will be in the opposite direction the bullet is fired and the magnitude will depend on the number you add for air friction (ie 0.07).

PS can anyone tell me what the air friction is of a 5.56x45 round or how to calculate it?

[4 IN 1 0]

so they are not there because BI somehow didnt give a value to it?

[fireship4 0]

Basically yes. Maybe you can add all the different values from different areas of the weapon config (ie the airfriction line from the missles, etc.) to each weapon/ammo/magazine in turn, therefore giving you more things to edit. This is the way I will do it from now on in the USTP project from now on.

[KaiserPanda 0]

I didn't look in to why bullets weren't dropping enough in flight, thank you for finding that out. If you can solve bullets not loosing velocity in ArmA and mod it, that would be fantastic.

[max power 21]

This is how to calculate 'wind resistence':

http://en.wikipedia.org/wiki/Ballistic_coefficient

[fireship4 0]

Thats an objects ability to overcome air resistance, not the amount of air resistance a 5.56 bullet has. I can probably find out myself if no-one knows.

EDIT: I found this which may be usefu - http://www.uslink.com/~tom1/calcbc/calcbc.htm#calculator

I could use 1 minus BC (like plaintiff1 has just mentioned below) for the value that i give to weapons, I'll see if this works later today.

I have also read that BC changes over distance and with velocity anyway, but this is too hard to model (for starters anyway).

[max power 21]

I was under the impression that you could derive it from that concept.

This one might be more helpful.

http://en.wikipedia.org/wiki/Drag_equation

Here is a graph showing the coefficient of zero yaw drag for NATO bullets at different mach situations.

This was taken from this page, which is an extensive presentation on the flight of bullets:

http://www.nennstiel-ruprecht.de/bullfly/index.htm#Contents

If you take the Coefficient of drag from the initspeed of the bullet, then you will have poor terminal effectiveness... If you take the subsonic coefficient of drag, you will get superior terminal effectiveness. You're going to have to tune those settings using some real-world data.. and even then, finding the coefficient of drag of the east block stuff and more exotic bullets like the .50 match might not be so easy!

[whisper 0]

Knowing that damage is already derived from bullet speed by ArmA engine, this is pretty important finding here!

fireship, did you use sideAirFriction or airFriction parameter?

[4 IN 1 0]

this is the first time i get really really looking forward for the result!

[Iron+Cross 0]

GOD BLESS YOU fireship4 Thats a killer find for us all!! thank you..

Question now is how mutch extra CPU/RAM load dose it cost to add this to every bullet?? (will it lag more in sp/MP)

& the main question dose it work in MP, what i mean is dose the air friction calculation work in MP & dose it work the same?

[fireship4 0]

Hooray! Now Zoidberg is the popular one!

I used sideairfriction - didnt know there was another.

[whisper 0]

there is this :

http://community.bistudio.com/wiki....riction

It is in cfgVehicles, though, so not sure it is really related

[twisted 127]

it would be great if a modified config could be released that combines realistic rates of fire with the discovery from fireship4.

[4 IN 1 0]

 GOD BLESS YOU fireship4 Thats a killer find for us all!! thank you..

Question now is how mutch extra CPU/RAM load dose it cost to add this to every bullet?? (will it lag more in sp/MP)

& the main question dose it work in MP, what i mean is dose the air friction calculation work in MP & dose it work the same?

if it is done through engine instead of extra script, the engine load will not be too much

[canukausiuka 1]

Another thing to consider is how well the AI corrects for it. If the AI can't hit anything at distance because of the correction, I don't know how useful it will be to actually implement.

Definitely worth looking into though