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Bad hit handling on Tanks: near invulnerable, rounds overpenetrating, crew/cargo unaffected by hits. Repro inside.
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See inside, Mission setup with 1x M2 vs a BTR-K filled with civilians. Access civilians via teamswitch (u) after firing at the BTR-K to observe casualties.

Note that hits directly into the cargo compartement will not kill 3 out of 5 times, and if they kill, they will only affect one or at best two inside the compartement.

Further, almost always will the round be observed to overpenetrate and strike ground far behind the target.

An APFSDS round will not overpenetrate an armoured target because it -disintegrates into a nuclear ball of fire- inside the vehicle. Not only will a moving vehicle, 50 tons in weight and moving at 30 kph be brought to a -dead stop- when hit in the frontal arc for a microsecond by the hit, but its inside will also be ravaged by the blastwave, burning uranium/tungsten dust and shrapnel, and armour spalls and fragments blasting through the insides.

APFSDS penetrators will only overpenetrate a target with very little armor (for example, a BMP cargo compartement from the side, or a civilian vehicle.) but will not overpenetrate an armored vehicle like the BTR-K, lengthwise.

Why are there no distinct hitzones for ammo compartements, individual crewmembers, mission critical equipment, etc? {F21936} {F21937}


Legacy ID
Steps To Reproduce

Place any Tank, fire against any other vehicle, and observe overpenetrating APFSDS rounds as well as no damage to crew and vehicle.

Event Timeline

InstaGoat edited Steps To Reproduce. (Show Details)Sep 5 2013, 5:24 PM
InstaGoat edited Additional Information. (Show Details)
InstaGoat set Category to Config.
InstaGoat set Reproducibility to Always.
InstaGoat set Severity to None.
InstaGoat set Resolution to Fixed.
InstaGoat set Legacy ID to 1819834822.May 7 2016, 4:32 PM
InstaGoat edited a custom field.
Bohemia added a subscriber: zGuba.Sep 5 2013, 5:24 PM

It seems you have misconception about momentum ... a 50 ton vehicle will NEVER "dead stop" from a sabot round . It is designed for penetration and it does not explode inside the vehicle , it's the heat gained in flight that does the "burning" damage if any .

Also not sure about going all the way through the btr-k but the devs said it has poor armor so i would count it as possible .

I am quoting from Bundeswehr tests done in the 80s, to which I have no access anymore since my dad sold his books. (bad argument, I know.)

They made an M-48 travel at 30 kph and shot it from 1500 meters with a 105mm Leopard 1 APFSDS round. The tank stopped dead for a fraction of a second from the force, before continuing on at its previous speed. The time where it was slowed down was during the moment that the KE penetrator punched through the front armor.

APFSDS rounds are made from high density materials, tungsten and depleted uranium. They do not heat up during flight to any significant degree. They heat when impacting, because the energy they carry has to go somewhere, it can't push the material away, so it heats up. The temperature on the inside of the penetrators impact is in excess of 10.000° centigrade. For a flash of a moment, it is hotter than the surface of the sun (5000~°K).

Additionally to that searing hot blast of disintegrating uranium, you have high speed spalling and fragmenting, overpressure blowing panels off every piece of equipment and setting anything that can burn on fire.

A typical russian made KE round has an impact force around 240 Megajoules that need to be turned into -something- when it strikes. And that is a plasma jet that will either blast a glowing crater into your armor, or come out on the inside and give you an impression of what the photosphere of our star is like.

zGuba added a comment.Sep 6 2013, 12:10 AM

Thanks InstaGoat.

We worked hard to make the penetration in A3 as good as possible. However there are technical limitations for simulation of penetration we have; currently the engine does not feature disintegration of projectiles after penetration, as it should occur with SABOTs; this is probably the reason for issues described.

Side notes:

  • all armored vehicles in A3 have weak points: zones like engine, ammo compartments, turret mechanisms, crew members receive damage from explosions and penetrating shots, both as a "hitpoint" and for whole vehicle.
  • the BTR-K is lightly armored vehicle, it's armor is mostly comparable with wheeled APCs we have ingame. I would expect the 120mm SABOT under normal conditions to pierce two 30mm RHA plates with ease.

Red Orchestra 2 tanks are a good example on hit handling on tanks. Crewmembers die if hit, specific zones of the vehicle are marked as engine and ammunition, the armour is weaker on the sides and rear, also there are weak spots in the armour allowing you to easily take out the crew inside, even on the front with an AT rifle.

I don't seem to understand the stopped dead thing :| , then i assume you mean that it will have an impact on its speed but not stopped? , this is true but it won't make much of a change other than a good shake :)

But generally a round does not have enough momentum to dead stop (literally stop) a tank , just do the math p=m*u , in my calculations i used 4Kg for the mass of the round and 50 tons for the tank with 1900m/s for the round and 8,3 m/s (30Km/h) for the tank.

I am not sure about the mass of the round though , i made some rough calculations based on uranium density and the volume from the dimensions of a typical sabot round.

Depleted uranium can ignite on its own in high temperatures but considering the friction at these high speeds this is almost certain at least on impact .

Also the energy goes to the vehicle as both heat and deformation but mostly as deformation (to archive penetration) and when penetration happens the round still hasn't given all of its energy as it is still in motion inside the vehicle. Deformation also happens on the round and that's also some energy lost

There may be also heated fragments (mostly from the vehicle itself i believe) inside the vehicle but i highly doubt that the round itself will end up disintegrating into plasma .

I am not an arms expert so my limited arms knowledge comes from the net and wikipedia which says that APFSDS rounds generally operate in the range of 1,400 to 1,900 m/s and with the max listed velocity and a round of 4 Kg mass it only gives energy of 7,22 Megajoules .

Anyway as i stated i am not an arms expert i just love physics so i might just say nonsense :) but with the numbers i gathered around it just impossible to have a round produce 240 Megajoules of energy (that's a lot!).

And all these are not to say that collateral damage is impossible as hot air alone can burn a person's face but setting up the vehicle on fire if it does not make contact with something flammable (fuel,ammo,seats for example) in my opinion is unlikely .

In my opinion there should be major hull damage/deformation and death to any passengers in close proximity from point of impact , deformation should affect vehicle movement performance.

Don't forget that APFSDS is designed for armor penetration and not to explode :) .

Byku added a subscriber: Byku.May 7 2016, 4:32 PM

The calculation I used to get the energy was Ke = 0.5 * M * V² where Ke gives energy in joule, M is projectile mass in Kgs and V is velocity in m/sec.

I didn't write down the numbers I used, but I know that I fudged the weight of the projectile (went way too high), and I completely got the energy number wrong. My new one is better and coincides with numbers people who actually understand math have come up with.

For example, a 1980s 125mm Sabot of soviet production will weigh around 4800 grams (4.8 kg) and have a muzzle velocity of about 1600 m/sec.

So that gives 6144000 joule of muzzle energy. Project Rho's boom table gives an energy of 6.1 x 10^06 joule for the US made 120 apfsds penetrator, so that seems to be about correct. Again, I fudged the decimals, so that number is actual 6.1 megajoule, not my extraordinarily high number above.

Still, especially DU rounds will cause damage not just by penetration and spalling, because depleted uranium is pyrophoric, ie, it will ignite on contact with air if heated sufficiently. The actual event that happens on impact is actually something we do not know a lot about, some argue that the round turns into plasma spray, some say it doesn't, but there doesn't seem to be a scientific concensus yet.

Fact is that it gets extremely hot inside the tank, you get blast overpressure from the shockwave of the round boring through the inside of the tank that will blow off anything that isn't tied down, and the burning uranium fragments will set anything that can burn on fire and melt anything that doesn't unless it is made of steel.

The website I quoted above and that Byku already linked is a pretty decent source for russian made KE weaponery. These are generally less effective than western ones, since they are lighter and shorter. Longer projectiles seem to have better penetration.

zGuba: Thanks, maybe there can be some sort of workaround to make the impact harsher on the crew?

Maybe some sort of functionality similar to the aircraft could also be added where sensors stop functioning after a hit, rangefinder, zeroing, optics modes, etc?

You shouldn't underestimate the Russians :D , velocity is squared and therefore plays a far bigger role in the energy output of the round than its mass :) .

An other thing is that we calculated the muzzle energy of the weapon (point blank shots) and not the energy upon impact which is heavily dependent on distance traveled .

I tested the btr-k with the slammer tank it reacts weirdly , sometimes when hit it just explodes right away , sometimes it takes no damage at all .

I believe what we are asking here in general is an advanced damage model for vehicles which is an old subject and community wish.

Also thanks for the informing site guys.

Byku added a comment.Sep 12 2013, 12:21 AM

What also I believe you should look into is the damage from 30-40mm guns. Currently AA tank will wreck a T-100. Put T-100 AI and Cheetah on map and look. Furthermore, as you don't have proper sabot simulation, wouldn't it be better and easier to make specific zones bigger so it would be easier to hit the engine or turret? As a small example, when in T-100 i've hit Cheetah turret directly from 100meters, no damage to it.

Kirill added a subscriber: Kirill.May 7 2016, 4:32 PM

I think generally non-penetrating shots should be less, penetrating shots more damaging. Right now there seems to be no differentiation between the two, and the only way to single-shot any tank is to hit the engine. Even for the Marid I need an average of three shots before disabling it using apfsds, which is excessive.

Damage to the vehicles at large is not as significant as damage to crew and components, such as optics. Ability to damage and disable optics and crew should be improved, I think, the damage against the vehicles per se is okay. Also, internal fires should be simulated, so even if the vehicle survives a hit, it may still burst into flames after a while. Can this be feasibly done without scripting a hack on, so the modders can be spared reinventing this wheel again?

zGuba added a comment.Sep 16 2013, 9:15 PM

A HitHull class in HitPoints offers such feature - when it reaches > 0.9, the tank "catches fire" and explodes or burns a while later.

So, yes, there is still big room for improvements in that matter. ;)

Perhaps it is worth adding the third simple effect - smoke without fire.

zGuba added a comment.Sep 23 2013, 4:11 PM

Some issues will be improved soon-ish.

zGuba added a comment.Sep 30 2013, 9:15 PM

The improvement on APC damage handling is still pending.
I'll work on turret damage handling during course of October.

From watching and playing some missions, it is beginning to look better now. I saw a helo catch on fire mid air and attempt a landing, that was quite nice. Did you enable that recently, or was that a fluke?

zGuba added a comment.Oct 2 2013, 1:16 AM

Helicopters are not my area of work... at least in A3.

maturin added a subscriber: maturin.May 7 2016, 4:32 PM

The problem is that a sabot is just 30mm (ish) wide. The game handles it as one big bullet, whereas it should be treating it as a cloud of spall and heat. Penetration is simply insufficient for modeling crew damage.

Quantti added a subscriber: Quantti.May 7 2016, 4:32 PM

"APFSDS penetrators will only overpenetrate a target with very little armor" -InstaGoat

This is untrue since there are documented cases of 120mm APFSDS fully penetrating T-72's and even M1A1's in friendy fire cases. See pic I uploaded.

But in the game there are cases where a 120m APFSDS rounds penetrates a whole Slammer tank hitting the crew compartment and even the hull doesn't take damage, please fix this bug.

zGuba added a comment.Nov 28 2013, 4:43 PM

Generally fixed for all armoured vehicles. I'll only fix reported detail problems since now.

Goose added a subscriber: Goose.May 7 2016, 4:32 PM
Goose added a comment.Nov 29 2013, 4:33 AM

"This is untrue since there are documented cases of 120mm APFSDS fully penetrating T-72's and even M1A1's in friendy fire cases."

Exactly, and many of the people in vehicles hit by DU penetrators survived, check the friendly fire incidents... a "nuclear ball of fire"? Sorry, no, that's fiction, DU is pyrophoric, what happens is it can ignite ammunition / fuel.

It can't bring a moving tank to a halt either, let's see, 41.5 tonne T72 at 30 km/h has 3.458*10^5 N*s momentum, it is hit by an M829A1 penetrator weighing 4.6 kg with an impact velocity of 1545 m/s (~500m range), the penetrator has 7.107*10^3 N*s momentum, best case scenario, assume it stops dead on the armor transferring all it's energy immediately, inelastic collision (yeah right)

So we can calculate the tank's speed after the impact, 29.4 km/h, hardly slowed it at all, only 0.6 km/h. And in real life the penetrator would go through the armor like it was butter, meaning even less effect on the immediate speed of the tank.

Mass closing resolved issues not updated since November.