Defensive Combat Bug

  • As it seems that we can discuss bugs, I would like to make this combat bug known to everyone as it’s very easy to be affected by.


    Basically, there’s a bug in the melee combat system when there’s a combat in a city and there are 2 or more groups defending. The defenders don’t do anything to create the bug nor can they avoid it.


    To show you in numbers, I did various tests of 50+50 defending against a stack of 100 units attacking, the results were:


    Combat: 50 (98%) + 50 (94%) vs 100 (93%)

    Result: 26 (76%) + 25 (78%) vs 0

    Losses: 51 / 100


    Combat: 50 (95%) + 50 (92%) vs 100 (87%)

    Result: 25 (78%) + 24 (67%) vs 0

    Losses: 51 / 100


    Combat: 50 (98%) + 50 (91%) vs 100 (89%)

    Result: 28 (83%) + 31 (74%) vs 0

    Losses: 59 / 100


    The morale is a bit lower in the attackers side, but no way does it explain the 2/1 difference in a combat that should actually be a bit more favourable to the larger stack.


    What seems to happen is that the defenders both independently attack the attacker with all their attack damage (as it should be), but the attacker only attacks once (here is the bug). The attacker should combat with each stack independently, so it should attack twice. Also, the defending stacks will appear as if they are not in combat when they are (no combat symbol and doesn't say they are in combat).


    I did many more tests with this bug, and if there are more than 2 groups in the city, the results are even worse.


    - 10 stacks of 100 defending vs 1000 attackers, the results were that defenders lost just over 100 troops while the attackers lost everything.. So losses at 10/1.

    - Let's say the defender has 200 troops and is being attacked by 1000 troops, defender can divide in to stacks and defeat the attacker in a 5/1 inferiority...


    The more stacks there are, the higher the difference and the defender can actually create stacks with it's own troops, he doesn't even need an ally to defend the city. So yes, this is a gamebreaking bug.


    This bug has existed for many years, at least 5... I reported this a couple of years ago too, through the Bug Brigade, with plenty of tests, details, screenshots, etc.


    Some veterans might remember how some alliances were capable of winning combats with a 5/1 loss ratio during the alliance league, the ISAC tournament, etc., these bugs in the combat system have completely destroyed the alliances. I myself organised a alliance tournament last year in the Spanish server with 16 alliances and it had to be ended due to disputes over this bug. But of course, this doesn't just affect alliance games, it affects every single game..


    There are more combat bugs similar to this one, but this is it for now.

  • That is correct


    splash damage

    factor x

    lost dmg while passing it from one unit to another


    plus smaller units gets always better scores than bigger units- IMHO it is some hardcoded behavior, the less defenders , the harder to kill them and they still deal a lot of dmg. Sometimes I killed 85 of 100 enemy units and they were still dealing half a dmg that 100 was giving me .... hardcoded to artificially prolong battles and give better experience to smaller players. Similar to Frank faction in Atilla TW. Dmg rises proportionally to casualties.

  • No, it has nothing to do with what you are saying, none of that explains that 100 troops can beat 1000 troops... These are just some of the results to explain it, but we did many more tests.


    This has been tested and retested many times, it has been discussed by players and mods that know a lot about the game and it has been confirmed as a bug. So just because you don't know it, doesn't make it untrue.


    Let's keep this to the point please.. If you don't believe it, do some tests yourself and you will see the results.

  • not sure what you are saying but I agreed that you are correct. Dividing is always better.

    and system worked the same way since I remember in 2010, they tried to nerf it by hardcoding around 2014 , when they were also creating battle engine for COW, but the truth is that huge stacks were always at disadvantage, even after nerf. So if they havent managed to fix it in 2014 - it means it will never be fixed as it is spread all over the code.


    I can only guess that original design idea was to have more mobile gameplay than static one with two stacks of 50 mln shooting each other for weeks. This is why you have cap limits of 50, this is why dying units always perform better. Talk also to players with top military scores, talk to devs and programmers from bytro as they should have info that you need.


    if you can - send me those tests of yours for small units below 100, medium up to million and huge above million . Check also Petruz's damage bot to get additional info. I believe Petruz said that to have efficient smaller stacks they should in theory have 40% dmg power of a big stack. I would personally go for dmg of same size just as a rule. Talk to Petruz plz - he will explain you that behavior.

  • Though you were saying that the results were normal/correct and justifying the results with those things, my bad if you dind't mean that.


    I'm afraid I have lost all the results, stats and screenshots.. I only have extracts of conversations and posts on out alliance forum. Most was posted on the bug brigade skype group but I'm no longer in it. Not sure what you mean at the end about Petruz, is that about the damage efficiency?


    Tests can easily be done by a GO in a pioneer game, they have the power to speedup games and skip ahead an hour, 24 hours, etc.

  • Petruz figured out in Theory how to divide stacks into smaller baby-stacks. He is convinced that having baby stack of 40% damage of enemy stack is quite optimal size.

    I still think it is better to have more, like 1:1 dmg comparision with a big stack but it is my idea that I use without any argumetns behind. It just works for me with a new off a defensive values introduced in a last update.


    But Petruz explained me that I have not understood your bug correctly as you are aware of size factor. What you are saying is:

    1 .Bug puts in disadvantage single attacking stack fighting multiple defending armies.

    2. Bug also supports multiple attacking armies vs one single stack even though they are smaller.


    now my question is - have you tried that: :

    A.Have you tested bug on home, enemy and neutral territories? I believe picking up enemy away from his provinces will get you much better results.

    B. If we have multiple defending armies they should not attack attacker if they want to avoid losses- this means they cannot move. So if they are from one nation they should stand next to each other, keeping distance so they do not merge, which allows attacker to pick them roughly on by one

    C. Same as B. but with different defending nations in one fort - I believe diplomacy could help here if they havent nerfed it.

    D. If you are still not sure if you can make it - there is always possibility of blockade- you stand 30 mins from opponent blocking bis movement and both your troops and enemy troops are unavalaible for some time without takign any losses.

  • Petruz figured out in Theory how to divide stacks into smaller baby-stacks. He is convinced that having baby stack of 40% damage of enemy stack is quite optimal size.

    I still think it is better to have more, like 1:1 dmg comparision with a big stack but it is my idea that I use without any argumetns behind. It just works for me with a new off a defensive values introduced in a last update.

    I'm not sure about that theory, I have always felt that dividing troops always makes you lose more troops. In a 50+50 vs 100, the bigger group should have advantage as there will 2 independent combats of 50vs100, so the larger group will start off the combat with higher resistance. But I haven't read his theory, so can't say really.


    But Petruz explained me that I have not understood your bug correctly as you are aware of size factor. What you are saying is:

    1 .Bug puts in disadvantage single attacking stack fighting multiple defending armies.

    2. Bug also supports multiple attacking armies vs one single stack even though they are smaller.

    1. Yes, but only when this happens in a city.

    2. No, bug only happens when troops defend the city, many stacks of attacker don't get bugged.


    Have you tested bug on home, enemy and neutral territories? I believe picking up enemy away from his provinces will get you much better results.

    It only happens when troops are all together in a city without moving. If you do the same tests in any other situation, even in the same province but outside the city, there will a normal combat (attacker will attack each stack independently), the results will be very different.

    B. If we have multiple defending armies they should not attack attacker if they want to avoid losses- this means they cannot move. So if they are from one nation they should stand next to each other, keeping distance so they do not merge, which allows attacker to pick them roughly on by one

    They can be in the same point by giving them an order and delaying it, that way they all sit in the same spot. If you stand them next to each other, the bug won't happen.


    C. Same as B. but with different defending nations in one fort - I believe diplomacy could help here if they havent nerfed it.

    Yes, the diplomacy bug also affects this both ways.. The defender can also do the diplomacy bug causing a lot of damage to the attackers. Haven't tested the attacker doing the diplomacy changes, but I do remember it was hard to break this bug.. Tried to see if there was a way to make the defending troops come out of the bug, but couldn't find one.






    Edit on original post:

    What seems tohappen is that the defenders both independently attack the attacker with alltheir attack damage (as it should be), but the attacker only attacks once (hereis the bug). The attacker should combat with each stack independently, so itshould attack twice. Also, the defending stacks will appear as if they are not in combat when they are (no combat symbol and doesn't say they are in combat).

  • Hi


    1. From your tests looks that both defendign stacks are gettign dmg so applying splash damage works fine. Lets focus where dmg is lost.

    2. With every engagement there is a dice roll for a fight round- so the more dice rolls you have , the better chance you will get better scores. One stack has bigger chance to get worse scores.

    3. I believe that when splash dmg is applied it has to be rounded down so it can be passed to the next stack in area in a convenient way . This is how you lose some dmg in my opinion.

    4. Bytro lately supported idea of smaller units fighting better against overhelming odds and 1 inf can survive barrage from 50 arts. I believe it is hardcoded to prolong battles and give satisfaction to smalelr nations but I can be wrong. This would also affected dmg dealt by bigger stack to a shrinking enemy- less dmg every time enemy is smaller.

    In that equation dmg is somehow proportional to enemy size: smaller enemy- less dmg....

    I believe everyone can confirm that after last update.



    I once attacked enemy force of around 10 kk with my stack divided in 20 smaller stacks of 500 inf 50 tanks 50 cars 50 cavs 15 HTs and some ballons . I had to help my guys with 4 k planes. But from what I saw smaller stacks where not so effective as i thought in an attack so I would risk statement that melee defending is a better option that attacking. my 20 meee mini-stacks had overhelming dmg but were killing not more 1.5-2 kk. Dmg got magically spread all over the map. While at the same time 18*50 arts were roughly killing 6kk-.7.5kk mln troops per round.

  • I once attacked enemy force of around 10 kk with my stack divided in 20 smaller stacks of 500 inf 50 tanks 50 cars 50 cavs 15 HTs and some ballons . I had to help my guys with 4 k planes. But from what I saw smaller stacks where not so effective as i thought in an attack so I would risk statement that melee defending is a better option that attacking. my 20 meee mini-stacks had overhelming dmg but were killing not more 1.5-2 kk. Dmg got magically spread all over the map. While at the same time 18*50 arts were roughly killing 6kk-.7.5kk mln troops per round.

    The thing is when you divide, the big group attacks every little stack independently, so big group will always have the advange if the other conditions are equal (same morale, damage attack, etc.). I have also done tests on same troops attacking and defending a city (50v50, 100v100, etc) and there were no differences, it doesn't matter if you attack or defend a city, it was random which side won. So this doesn't have anything to do with that.


    The only thing you need to confirm the bug is:

    A) 5 stacks of 50 defending in a city against 300 troops.

    B) 5 stacks of 50 anywhere that's not a city against 300 troops.


    You will see there is a huge difference in the results.. I would say that defenders will win in A with less than 100 losses, while attackers will win in B with just over 50 troops remaining. But in theory, results should be more or less the same.


    The bug is simply that the attacker only attacks once when it should actually attack each stack independently. Example:


    5 stacks of 50 vs 300. The 5 groups of 50 will each attack the group of 300, so the group of 300 should attack each stack of 50 too, so there would 5 independent battles. What the bug does, is that the attackers only attack once and spreads between all the stacks, reducing it's attack by a 20%..

  • Ahh now I see


    in field - you attack every group, in town - just one.

    use the force LUKE and conquer town with a garrison first.,using my bug Then you will be sitting in a town and laughing .


    but it also confirms that spreading defense overcomes enemy numerical advantage and should with smaller effect, but always with some bonus, help outside town too.

    ow towns became more important for me - thanks Sckopen.

  • To explain this bug:


    It has to do with the way size factors (SBDE) and splash damage are calculated. An army is always spreading its damage among all enemies in a 5km circle around the point of attack (splash damage). In turn also all enemies in that 5km radius defend back, and their damage values are added up.

    The problem is that the size factors (SBDE) are calculated for each enemy stack individually instead of calculating the size factors after adding the damages together. The result is that SBDE limits are circumvented.


    Example: Lets say the stack limit of a unit would be 50 and each unit deals 1 damage. If 5 stacks of 50 of these units are attacked in the same position, their return damage is 250 instead of 50, like it would be for a single stack of 250 of these units.


    In fights where both sides attack each other (on paths for example) this is often alleviated a bit, because also the multiple stacks would attack the single stack and get return damage each time they attack, making the fights more even than fights where only one side attacks or defends.


    This bug is also the reason for the "plane patrol exploit" (known more in the CoW community) or the "flower bouqet exploit". All share the same underlying reason.

    So in order to fix this bug we would need to rewrite the combat calculation in a way that size factors are applied after adding up damage values. Or by making an attacking army attacking each army in an area individually instead of spreading its damage among all of them. It could also be alleviated a bit by removing the functionality that in certain situations only one side in a battle attacks and one only defends.

    There is no immediate solution in sight and I won't make any promises here if or when and how this will be fixed, although we will certainly talk about it again in the team and may put it on an agenda to investigate this again in detail.


    Until this is fixed I personally would argue for allowing to use this bug (but that call should be made by the CMs & support staff), as it is too hard to judge if someone is using this intentionally or accidentally (e.g. you cannot really punish someone just for defending an allied city together with his ally, most people don't even know that this triggers the bug). Plus for example the plane patrol exploit is also not banned in CoW although it has the same reason, and we already allow even more decisive bug usage like Shoot'n'Scoot.

  • So basically, you are saying that splash damage is to blame for it. Troops only attack one stack which divides between all and then doesn't attack the rest of the stacks. But why doesn't this happen outside a city? It only happens when there are various defending stacks in a city (except for flower bouqet).


    The bug also only happens when the stacks aren't showing as in combat, sometimes they "join" the battle and appear as in combat which means bug ends and advantage is lost, combat goes back to normal.


    So in order to fix this bug we would need to rewrite the combat calculation in a way that size factors are applied after adding up damage values. Or by making an attacking army attacking each army in an area individually instead of spreading its damage among all of them.

    But why is the city combat different? I can't see why you have to change all this when combats are fine in other situations, can't you change the behaviour in the city? Find out why those stacks in the city seem to "stay out of combat" (allthough they are)?


    Or if splash damage really is the cause, couldn't this be removed? Then attackers would actually attack each stack.


    I don't agree in allowing a player to be able to divide his own troops, it's insane that he could defeat someone with 10 or 20 times more troops by simply dividing his troops. As for allied troops, I would simply allow as there is no way to prove if it's intentional or not. But I still think it's something that should be fixed even if it takes extra work.. Combat system has to be one of the most important things in a combat game.

  • All units deal attacking damage and defending damage, you can check that in the unit details panel. Normally during battles on paths, both sides attack each other using offensive damage, and also return defensive damage (basically 2 ticks in parallel). In cities or during disembarking or when a single patrol tick happens one side is only defending with its defensive damage and one side is only attacking with its attacking damage (only 1 tick happens then).


    So when meeting on a path both sides attack both ways and also defend both ways, which often times nullifies the advantage of multiple stacks. That's because each smaller stack attacks the bigger stack and each time gets defensive damage in return, just like the bigger stack gets defensive damage from each of the smaller stacks.


    That's why the bug is most often only noticeable when the side with the multiple stacks is defending only, due to the behaviour I explained in my previous post.



    Splash damage is there to prevent the exploit of splitting up stacks in alot of smaller chunks so that artillery shots or plane attacks are wasted for example, so just removing it is also no solution. And yeah removing the behaviour that troops only defend in certain situations should also solve most of these situations (though maybe not all edge cases). And although there would be several ways to fix this that sound easy on paper, implementing that is a different beast because the combat system is a giant knot with alot of possible edge cases, and changing it can break alot of things. We plan to touch the combat system anyway in the upcoming months and I will make sure that investigating this issue again is on the agenda for that.


    As for allowing players to use it until it is fixed: With shoot'n'scoot players already actively use an unintended bug that wields far greater advantages, with which its possible to defeat hundreds of enemy ranged units without losing any ranged units on your own. Allowing this but not allowing the splitting bug would be a little hypocritical in my eyes. It would also create alot of player reports that need to be checked and many of them probably cannot be proven, creating alot of support work, witch hunts and frustration. That's why I back the CM's statement that bug usage is allowed unless we announce it globally as a banned exploit or until we fix it. In this case it is "until we fix it".

  • All units deal attacking damage and defending damage, you can check that in the unit details panel. Normally during battles on paths, both sides attack each other using offensive damage, and also return defensive damage (basically 2 ticks in parallel). In cities or during disembarking or when a single patrol tick happens one side is only defending with its defensive damage and one side is only attacking with its attacking damage (only 1 tick happens then).


    So when meeting on a path both sides attack both ways and also defend both ways, which often times nullifies the advantage of multiple stacks. That's because each smaller stack attacks the bigger stack and each time gets defensive damage in return, just like the bigger stack gets defensive damage from each of the smaller stacks.


    That's why the bug is most often only noticeable when the side with the multiple stacks is defending only, due to the behaviour I explained in my previous post.

    I understand the difference between defensive & offesive damage, but haven't noticed any strange combats outside cities. So according to what you say, outside the city the advantage would be halved.. You would have one bugged round and a normal round. So if we had a combat with 10 stacks which in a city would be 10/1 favourable to the defenders, this must mean that it will be 5/1 favourable anywhere else. Will have to test it or maybe someone else might volunteer (as I'm not currently in any game).

    Splash damage is there to prevent the exploit of splitting up stacks in alot of smaller chunks so that artillery shots or plane attacks are wasted for example, so just removing it is also no solution

    I don't think it would be an issue with artilleries since you introduced the extra attack one minute after destroying the unit/group, but I guess it would with planes.


    And yeah removing the behaviour that troops only defend in certain situations should also solve most of these situations (though maybe not all edge cases).

    I was refering to the fact that the bugged troops appear as if they weren't in combat. The troops that defend a city appear as being attacked, but the bugged ones never do, so was wondering if it was clear why they stay like that as I thought it was what triggers the bug.


    That's why I back the CM's statement that bug usage is allowed unless we announce it globally as a banned exploit or until we fix it. In this case it is "until we fix it".

    Might or might not agree, but I asked for a clear answer and I believe I have it. So thanks for your responses Freezy ;)

  • I was refering to the fact that the bugged troops appear as if they weren't in combat. The troops that defend a city appear as being attacked, but the bugged ones never do, so was wondering if it was clear why they stay like that as I thought it was what triggers the bug.

    If an army is standing inside a city and is attacked, it won't have the combat symbol displayed and it will also not have the "next attack in ..." tooltip, and inside the army bar you will also not see "attacking XYZ". Instead, you will only see "is attacked by XYZ" in the army bar. When now 2 armies are standing in the same province, only one of them is directly targeted, because every army can only target 1 other army at the same time. That means that only one of the armies has the "is attacked by" written in the army bar. The other army however received splash damage of the attack, so effectively both armies are attacked and share the incoming damage, but only one of the armies is targeted so to say.

    So yeah the bug would likely also be solved if multiple units in the same attack location are directly targeted and all armies receive the full amount of damage, instead of the damage being split via splash damage. It would also make ranged weapons very strong against split stacks though, which may be an unwanted side effect. Maybe then another check would need to be implemented to only apply the new behaviour for close combat attacks. On the other hand maybe fixing the calculation of how defensive damage is returned is the more balanced solution, but it could have other pitfalls. Every solution has some tricks or edge cases, so we would need to investigate first how to best solve this, and then the fix itself will also be complicated and take quite some time, including through QA. That's why it wasnt done until now. We will see about the future.

  • Maybe remove splash damage from all non bombardment attacks? Then to circumvent an attack wasting bug, you could make melee attacks reserve their damage until all of their damage is dealt to any and all units.


    So for example if my 10 stack has 10 potential damage and you rush 10 stacks of 1 at them, my stack would damage and kill all of the 1 stacks until it is out of damage to give. And no matter what, once the next attack round starts, my stack would have it's full potential damage again.

  • Golden Frieza and I currently have a map in which we both have 20k x 1000 units easy enough to test this Bug under several scenario's (land/air/sea) to save data and to give screen shots... I have not heard Skopen mention mixing stacks as means to disburse damage, but seems someone mentioned multiple stacks are each individually doing defense damage against larger stack but still this does not explain the disparity in k/d also, splitting stacks is not supposed to make a difference as damage is capped at 50/40/30/etc...depending on the unit/mech involved in the melee....


    I am open to suggestions on how to properly document and reproduce this bug for purpose of future fairness in melee among players.

  • I am open to suggestions on how to properly document and reproduce this bug for purpose of future fairness in melee among players.

    Easy, you need 1 attacker and at least 2 defenders. Get 100 infantry to attack 1 city where it has 2 defenders, one of them being the owner and the other one and ally of the owner, they'll have 50 infantry each.

    Do that a few times and if you want to see even more disparity, add different defenders keeping the same total amount of infantry, if there are 4 defenders and the total is 100, then 25 each.


    Run some tests.


    In order to compare the results, do the same outside a city, in plain road.


    Allegledly, you should see a big difference in results.


    No need for any fortress or buildings in the city

    https://www.youtube.com/watch?v=-HA8kSdsf_M


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