Bombs are too slow!

[ray243 11]

Well, its a little something that annoys me, Its the fact that bombs fly so slow to the targets. From those explosion videos, the bombs almost came instantly, and I can hardly see the bombs. Its just a small thing I hope devs might fixed.

[11aTony 0]

I find the gbu12 for example quite realistic although I am not an expert. Are you?

[ray243 11]

Nope. But I can always see the bomb drifting slowly towards the target.

[[aps]gnat 28]

Is this laser guided bombs?

Yes .... the laser targeting code causes bombs to almost *float* their way to target.

[DillonAero 10]

I thought bombs are only as fast as gravity allows? Even LGBs rely mainly on gravity, with a system to make adjustments to the downward glidepath. I wouldn't expect it to be lightning fast like a missile.

[tj72 0]

Bombs are released at the speed of the plane at time of dropping. Im not sure if the laser target system slows it down or takes over its normal gravity. If the plane dropping the LGB is too slow the bomb will likely fall short. If too fast the guided bomb may overshoot but not as likely.

I recently made a script to manually angle a dumb LGB to a target position on the way down and it seemed like aiming the bomb to the target too soon caused the undershot to happen. Letting the momentum carry the bomb straight for a time to get a steep enough angle to target and then start pointing at the ground worked better. I think close to 600+ is good high altitude dropping speed.

[ray243 11]

Gnat;1810952']Is this laser guided bombs?

Yes .... the laser targeting code causes bombs to almost *float* their way to target.

Yeah, mostly LGBs.

[Tankbuster 1747]

Drop bombs from a hovering Harrier or F35 for even more comedy physics.

[max power 21]

I've heard that gravity in ArmA is somewhat less than it is in real life.

[Stinger656 10]

I've heard that gravity in ArmA is somewhat less than it is in real life.

Lol you are so right about that. For example when i dropped a GBU from my A-10 at a car it flew up in the air and stayed up in the air for about 30 seconds in one spot lol.

[vilas 477]

I've heard that gravity in ArmA is somewhat less than it is in real life.

probably there is reason

you can check it :

take flight to 300 m, stay there (Harrier, Mi24 with bomb, not aiming at target, or simply, jump off it without parashoote -if it is possible in game, but do it on sea level/beach, not on ground which will be higher than zero )

trow it

if gravity is real, it should fall to ground in :

t=\/^0.5 of (2*300/9.81)=7.8 seconds

if your bomb will fall in 7.8 sec, all will be okay

from 400 m ca. 9 s.

from 200 m ca. 6,3 s

Edited December 13, 2010 by vilas

[Stinger656 10]

probably there is reason

you can check it :

take flight to 300 m, stay there (Harrier, Mi24 with bomb, not aiming at target, or simply, jump off it without parashoote -if it is possible in game, but do it on sea level/beach, not on ground which will be higher than zero )

trow it

if gravity is real, it should fall to ground in :

t=\/^0.5 of (2*300/9.81)=7.8 seconds

if your bomb will fall in 7.8 sec, all will be okay

from 400 m ca. 9 s.

from 200 m ca. 6,3 s

Are you a mathematician lol?

[[aps]gnat 28]

@ray243,

Which island addon are you using?

Maybe the terrain makers are not making the ground suck hard enough.

[twisted 128]

probably there is reason

you can check it :

take flight to 300 m, stay there (Harrier, Mi24 with bomb, not aiming at target, or simply, jump off it without parashoote -if it is possible in game, but do it on sea level/beach, not on ground which will be higher than zero )

trow it

if gravity is real, it should fall to ground in :

t=\/^0.5 of (2*300/9.81)=7.8 seconds

if your bomb will fall in 7.8 sec, all will be okay

from 400 m ca. 9 s.

from 200 m ca. 6,3 s

interesting confirmation. is there a way for modders to fix it and would this also mean bullets drop slower than they should?

[max power 21]

What confirmation? He just did some kinematics to show how fast they should fall. There's nothing in there that shows how fast they do fall.

A short while ago there was a discussion about the time-to-target for bullets in ArmA. Bullets in ArmA are apparently too slow. I think the discussion turned to the fact that while the ballistic path of the bullets are correct, they take too long to get where they are going. This can only mean that they don't fall as you would predict. If a bullet falls the distance you predict but not in the time you predict, there must be something wrong with gravity.

Way back in OFP, there was some mention, regarding the difficulties of modding in OFP, about how the meters in the RV engine are slightly different from actual meters. For instance: If a bullet leaves the barrel at the correct muzzle velocity, follows the correct flight path, but takes too long to get to its target, then... ???

It would be interesting to know what happens if you change gravity. Do guided munitions still function? Can helicopters still fly? Can the AI still fly aircraft without killing themselves?

[vilas 477]

Are you a mathematician lol?

it is basic physics from secondary school in my country

S or h = (gt^2) / 2 (free falling kinetics)

so t = \/^0.5 of 2 S (or h) / gravitation acceleration (9.81 m/s2)

if you will jump from Arma plane on 200, 300 , 400 meters and you will fall ca. time I calculated it would mean that gravity in Arma is similar to real-life

if you will fall in 20 seconds instead of 9 seconds it would mean that gravity is twice smaller in game , which of course causes slow falling bombs, longer flight of bullet (Max told it)

cause gravity causes falling things , if bullet fly with given velocity, the bigger gravity - the faster it will fall

cause the same rule as for free falling - there is for bullet drop

bullet moves forward thanx to velocity, but falls also in time t = \/^0.5* 2h/g

if gravity was zero, than bullets would not have any curve in movement and any drop and zeroing (laser bullet or bullets in many shooter games when you have no bullet drop but all go straight )

the bigger gravity, the faster bullet goes down, but the bigger velocity, the farther it fly

when you shoot straight s = V0 * t (of course minus air Cx coefficient)

so if bullet fly far and it fly slow (reaches target in 3 seconds instead of 1 second) you know that something is not real with gravity and velocity

it is very important in term of mil-sim

why ?

cause when you fire from BMP (one mod in past had mistake) which has slow velocity cannon ( 650 m /s not 1500 like sabots) to another vehicle which moves perpendicular than you fire before vehicle

in time t HEAT will reach enemy vehicle

for example enemy vehicle is 1300 meters away (real BMP HEAT should fly in 2 seconds - circa about)

vehicle is moving 21 miles per hour/ 36 km/h, 10 m/s

so as you see in time of 2 seconds it will move for 20 meters, right ?

vehicle is 7 meters long, so ... you must fire 2-3 lenghts of vehicle before him, to hit him

right ?

but if in game you will fire at him and your grenade will hit ground and vehicle will be 10 meters away from hit point, it would mean that velocity is not realistic to real life

sniping with rifle i can observe the same, enemy soldier is running perpendicular 250 meters from me

i have SVD or Sako in game, so to shot him i need 0.3 second in real life , right ?

how much running man can move in 0.3 second (+ triger time) let's say 0.4 sec ?

1 or 2 meters ?

so fireing 1.5 in front of him i must catch him, but i missed

what does it mean ? it means that bullet flew to long , so both time and gravity in game is not perfect

so as topic issue - bombs fall to slow and noone can fix it except developer

[ray243 11]

Gnat;1812116']@ray243' date='

Which island addon are you using?

Maybe the terrain makers are not making the ground suck hard enough.[/quote']

It has nothing to do with the island. I tried on utes and other addon island, same thing happens.

http://www.youtube.com/watch?v=dBXqZ0TnXKA

Look at the speed of the bomb. You see it in one moment, the next, it blows up.

[max power 21]

It has nothing to do with the island. I tried on utes and other addon island, same thing happens.

http://www.youtube.com/watch?v=dBXqZ0TnXKA

Look at the speed of the bomb. You see it in one moment, the next, it blows up.

I think what he was saying is that there is a gravity property in each lsland's config file... not that there may be a problem with one island in particular.

[vilas 477]

island config contains cutscene, markers (names of cities) , icon path, file paths

not physics

[noubernou 77]

It is the simulation for shotRocket/shotMissile (bombs are considered missiles in ArmA2, at least they use the same simulation type).

There simulation there is really really really odd. Gravity has no major effect on them, the main thing is that they will point towards their target and go that way. I have seen ammo using the shotMissile property slow to less than 100m/s and still be flying perfectly level... basically they do not gain velocity correctly as they fall.

The only property that really seems to use gravity and air resistance correctly in ArmA2 is the simulation type used for shells. That can easily be confirmed because common ballistics code using basic math will predict the right distance and time of flight for a given elevation of fire. If that wasn't true the original BIS arty module would not have worked at all in terms of accuracy.

So why not switch the bombs to use the same simulation type as shells? Wellllll shells are harder to guide in this simulation type, in shot missile you can roughly steer the bombs using common vector commands, they will deviate course based off of the center of the models rotation, with shells... they just rotate around while still traveling in the same direction as before. In that case you have to go further and then simulate EVERYTHING for them including g-forces in turns and everything else that bleeds kinetic energy.

So yea... Thats the main reason.

On the other hand I have been able to make pretty convincing simulation of LGB and JDAM guidance using the normal bombs and they do hit pretty hard. I think the guidance code in the ArmA2 engine takes some liberties with the velocity.

[avengerzx 10]

The Mark 82 500lb JDAM flys faster to their targets (Low Drag Bombs)

[max power 21]

island config contains cutscene, markers (names of cities) , icon path, file paths

not physics

Well there you go :p

[maturin 12]

A short while ago there was a discussion about the time-to-target for bullets in ArmA. Bullets in ArmA are apparently too slow. I think the discussion turned to the fact that while the ballistic path of the bullets are correct, they take too long to get where they are going. This can only mean that they don't fall as you would predict. If a bullet falls the distance you predict but not in the time you predict, there must be something wrong with gravity.

The discussion I remember wasn't particularly scientific, with the only hard numbers involved a .6 seconds some guy just posted.

The most persuasive thing I heard was that air resistance is excessive in-game, slowing bullets too quickly. This will result in a slower round and a shorter-ranged one. It will also get you higher trajectories and extreme bullet drop at certain ranges.

But this sort of thing isn't for the layman to test. As many people have pointed out, there is a lag between bullet impact and dust spray, which throws everyone off.

[max power 21]

The discussion I remember wasn't particularly scientific, with the only hard numbers involved a .6 seconds some guy just posted.

The most persuasive thing I heard was that air resistance is excessive in-game, slowing bullets too quickly. This will result in a slower round and a shorter-ranged one. It will also get you higher trajectories and extreme bullet drop at certain ranges.

But this sort of thing isn't for the layman to test. As many people have pointed out, there is a lag between bullet impact and dust spray, which throws everyone off.

Right.. and if the people who claim that bullets are too slow are correct, and if the ballistic trajectories are correct as BIS claims, then something must be wrong with gravity also. From that thread, I seem to remember charts and a video, but I might be mistaken. Through his own testing, Vilas says that it's necessary to make vehicles much heavier than they should be in order to get them to stop behaving like toys (bouncing, flying around, etc). This could also be an indication that gravity is a little light in the ArmAversum. You're quite right to be sceptical, though. I agree with that.

[noubernou 77]

Right.. and if the people who claim that bullets are too slow are correct, and if the ballistic trajectories are correct as BIS claims, then something must be wrong with gravity also. From that thread, I seem to remember charts and a video, but I might be mistaken. Through his own testing, Vilas says that it's necessary to make vehicles much heavier than they should be in order to get them to stop behaving like toys (bouncing, flying around, etc). This could also be an indication that gravity is a little light in the ArmAversum. You're quite right to be sceptical, though. I agree with that.

Gravity is wrong for shotBullet then. Gravity works as expected in shotShell.

Thats the thing that people tend to forget/not know about how ArmA simulates things. Its not one giant cohesive system to simulate everything, but individual simulations written for specific entities, like bullets, cannon shells, missiles/rockets/bombs, cars, helicopters, planes, etc.