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HOI4 Dev Diary - Combat and Stats changes

Hi everyone and welcome back to another dev diary! Today is about various changes that affect combat and units. With the Barbarossa update we want to shake up the meta a bit and also change a few stats and other aspects to make using the tank designer more interesting and rewarding.

High Command bonus changes
For a long time now unit bonuses from high command have confused people. Most expect that they apply to battalions, when in fact they apply only if their target unit type was “the majority type”, which was basically a weighted type count. They also could overlap, so infantry, mountaineers and artillery would apply to the same units letting you stack stuff in ways that was never intended and quite unintuitive.

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This system has now changed, and divisions get bonuses based on their composition, this is a straight up ratio based on the number of non-support battalions of each type, so a 2x artillery 3x infantry division will be 40% artillery 60% infantry.
Battalions are always classified as a single type for this (even though some are scripted with multiple types) based on this priority:
cavalry > armor > artillery > motorized > mechanized > infantry

The exceptions being rocket & special forces, which both act as an addition, so if the 3 infantry divisions in the example above were mountain units, then the division would also be 60% special forces and if the 2 artillery are nebelwerfers it'd also be 40% rocket

When counting the battalions of armies (ie when we have an actual unit and not only a division template), battalions that lack equipment will count as less, so a Light Tank battalion with only half it's tanks will count as 0.5 battalions (and not count at all if without tanks). The total sum of the compositions will still end up 100% (unless every battalion is without equipment).

Screenshot_3.png


To make it easier to see this we now have an indicator in the division windows showing the breakdown.

Combat Width
As a part of our efforts to shake up the 40/20 width meta, we have made changes to the combat width of province terrain. Province widths now range from 75 to 96. Plains have a new base combat width of 90, while Mountains have a new combat width of 75. Most of these widths will not divide into each other easily, hopefully moving the ideal width away from multiples of 10.

Urban provinces are now the “widest” with a width of 96. But this does not mean they will be the easiest provinces to overwhelm. Mountains, marshes, and urban provinces now have reinforcement widths of ⅓ of province width instead of ½. This should hopefully give these provinces a slight defensive buff, while allowing us to open up pushing power in the more open tiles.


Screenshot_2.png


In conjunction with these changes, we have also been looking at reducing the overstacking penalty. We hope that this will alleviate some of the need to have divisions that are the perfect width for a given province. But at the same time, smaller countries should now be able to specialize their division width to suit their home terrain more appropriately.

Breakdown (numbers not final etc etc)
  • Plains
    • Standard 90
    • Reinforce 45
  • Desert
    • Standard 90
    • Reinforce 45
  • Forest
    • Standard 84
    • Reinforce 42
  • Jungle
    • Standard 84
    • Reinforce 42
  • Hills
    • Standard 80
    • Reinforce 40
  • Marsh
    • Standard 78
    • Reinforce 26
  • Urban
    • Standard 96
    • Reinforce.32
  • Mountain
    • Standard 75
    • Reinforce 25
One of the major things that make larger divisions like 40 width armor hit disproportionally harder than smaller ones is also how targeting and damage works inside combat in relation to the enemies defense. Essentially the larger divisions make more efficient use of concentrated damage as it punches through defense. To solve this we are doing a few things. First of all we are weighting the targeting towards wider divisions being more likely targets and also when picking targets to try and match it to have wider divisions spread damage over smaller rather than always concentrating it. They will probably still hit harder, but combined with width changes and other downsides of larger divisions it should make it less clear cut.
However, this part isn’t quite done yet though so I’ll cover it again in more detail in one of the “bag of tricks” diaries in the future when i see how it pans out, but I figured it needed to be mentioned now ;) That said though, to wet your appetites here is a little tease from a debug mapmode in development...
1620214309589.png


Armor and Piercing
Currently the effects of having stronger armor than the enemy can pierce, or being able to pierce an enemies armor are binary and give fixed bonuses. This meant that there wasn't really any benefit to have more armor than you needed to stop the enemies piercing, and also that being a single point of piercing under enemy armor was just as bad as having no piercing. So things were quite binary. With the tank designer coming we wanted to make it feel like your investments in upgrades were always worth it, so we are changing armor and piercing to have more gradual effects.

Armor > Piercing
  • Unit takes half damage (as it currently works)
Armor < Piercing and Amor > 0.75 * Piercing
  • Take damage between half damage to normal damage by difference in value
Armor < 0.75 * Piercing
  • The unit takes normal damage
Lets break this down with an example:
  • A panzer division has an armor value of 52
  • Its being attacked by an infantry division with some anti-tank guns. Their piercing is 60
  • If this was the old system this armor would be worthless and not reduce damage at all
  • Now because its close enough (between 60 and 45), so you get roughly half of the normal effect around 25% reduction of damage.

Reliability
For the tank designer it was important that reliability was more impactful if it was to be a good tradeoff with other aspects of design, so we needed to change it up (lest @CraniumMuppets 0% reliability tank monsters would take over the world). Now it will not just affect rate of loss in attrition but various other aspects:
  • Reliability affects losses from attrition like before
  • Reliability now affects org regain when moving, and also makes any weather related org effects more impactful when low
  • Lower reliability scales up all impacts from weather so if facing extreme weather a unit with low reliability equipment will suffer more of those weather effects
  • At the end of combat units with better reliability will be able to get back a certain amount of tanks etc to simulate that simple more reliable constructions would work better for battlefield repair and be less fragile when taking damage. So it's a bit like capturing enemy equipment in combat - but in reverse :cool:

Screenshot_4.png


Our goal is that this creates interesting tradeoffs when designing equipment and will make you have to consider if its worth switching a strategy focused on speed and firepower towards reliability when operating in bad weather and tough areas like the Russian winter or in northern africa or jungles.

Oh, and I figured now might be a good time to point out that there will be a future diary on weather changes and other cool related stuff, so these changes aren't completely in isolation. But one step at a time :)

But before we go, a few words about the studio...

Studio Gold
Hello everyone, my name is Thomas, but perhaps better known as @Besuchov here :)

As you saw here we have recently reorganized ourselves a little, moving from a big centralized Stockholm studio to splitting ourselves into Red, Green and Gold. This is mainly an internal org shift to make sure we keep our growing organization firmly focused around making good games. You shouldn't notice too many differences in the short term, we are still PDS making GSG on the Clausewitz engine, but it does mean that we can align each studio to the particular games. Since you will hear the studio names every once in a while, I just wanted to say who I am and what the studio is responsible for.

My role is Studio Manager, which means I'm accountable for the long term success of Studio Gold and working with things like management, staffing, and long term plans. Studio Gold has as its main focus Hearts of Iron (but we may or may not have some secret other stuff as well). Directly making the games though, that's still the job of Podcat and the team, but I intend to do my best to create an environment where we have the best chances to make great games together.

For me this is coming full circle at Paradox. I started as a programmer in 2004 and one of my first tasks was to work on Hearts of Iron 2. Since then I've done various things including being lead programmer for Hearts of Iron 3 (and Victoria 2), Project Lead for EU4 and more recently Studio Manager for PDS. Next to EU, HOI is my favorite game and I'm delighted to be back in a place where I can focus on fewer games and where that game is Hearts of Iron. You will see more of me in the future even though I will mostly take a backseat to the team working on the game.

That’s all, see you all again next week for more dev diary goodness!
 
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Pretty sure the Stalingrad province in hoi is larger than just the city limits, if anything it’s pretty analogous for a 200km diameter if not larger.
@Sourlol

If my analysis is correct, then:
  • province 3529 (Stalingrad) is made of 486 pixels. Note- used the GIMP grid tool to "count" the quantity of pixels in the HOI4 province id map.png
  • from defines MAP_SCALE_PIXEL_TO_KM = 7.114
  • therefore each pixel represents 7.114 km x 7.114 km = 50.6 square km per pixel
  • therefore province 3529 (Stalingrad) is 50.6 square km per pixel x 486 pixels = 24,596 square km
Assuming a perfect circle:
  • the area of the circle is 24,596 square km
  • the radius of the circle is the square root of (24,596/pi) = square root of (24,596/3.141529) = square root of (7,829 square km) = 88.5 km
  • the diameter of a circle is 2 x radius
  • therefore the Stalingrad province "diameter" = 2 x 88.5 km = 177 km
I do not know the actual geographical size of the Stalingrad city limits during the time of WW2. I will try to search for this info on the internet for a complete comparison. Others are more than welcome to provide this information as it might require Russian archives.

EDIT: My internet search did not reveal the geographical size of the Stalingrad city limits during the time of WW2. However, present day Volgograd (formerly named Stalingrad) has a geographical size of 859.4 square km.
 
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However the game is designed, I want to be able to optimize my gameplay. The game making itself impractical to optimize is something I disagree with. Every strategy game is just a set of optimization problems at its core. If the game discourages optimization by making it basically impossible, then it's not well designed in my opinion. And when they design different widths that ensure players are taking penalties no matter how they design their troops, that's kind of what they did.

The problem with forcing division design that doesn't equal the combat width of a battle is that you're going to be wasting whatever extra division joins the battle above the combat width. In the previous system an extra division would sit in the reserves until needed, but in the new system if there's even a little bit of free width (since divisions will be either a little bigger or a little smaller than some battles) a division will join the fight and take damage while providing no combat benefit to being there. It's just the game forcing you to waste resources.
While I agree that field manuals suggest a RANGE for combat width (not a single number - a range), real life forces commanders to make adjustments to the terrain. I do not know what your reasoning is not to model combat width a little closer to given terrain characteristics. Some players (me included) think that it adds flavor to the game and mixes things up a little. This does not mean that it is impractical to create optimized division, they are optimized for a certain situation.

Example - a small Finnish Jäger Division is ideal for the Karelian woods. They are made for that terrain. They would not stand a chance spread out over miles and miles of open field in the steppe.
No-one would burn out a highly mobile division in urban warfare (oh wait, yes some single German leader would...), because it is not made for that terrain.

It is very refreshing that the developers are are mixing things up a little.

And a little "historical nudge" - thinking in categories let the French military botch their defense in 1940. How could the Germans ever do the unthinkable and pass through the impassable Ardenne forest??? ;)
No flexibility there, my friend...
 
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Ahistorically, I might add. It's not like IRL a commander would roll in all their divisions' units into range of enemy artillery and then tell 3/4ths of them to take the day off and just wait to be shelled.

The general idea of combat width is pretty necessary to the game. Unfortunately, without making a system which splits divisions and keeps the others' mp/equipment from being affected (or better yet, lets them recover) having combat width like this will make it so that while bad divisions are less bad, it's much harder and less fun to make/use good divisions. I would have massively preferred a tactics rework with (more) terrain-specific tactics, where tactics were more closely connected to doctrine, where they were easier to understand for new players, and they had varied/dynamic effects, such as contributing to breakthrough/defense, or modifying enemy stats.
So, it would have to be a choive between infantry or mobile forces? And both is not possible?
If that is what you suggest - I think we have something like that already.

Otherwise - what would your idea look like?
 
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While I agree that field manuals suggest a RANGE for combat width (not a single number - a range), real life forces commanders to make adjustments to the terrain. I do not know what your reasoning is not to model combat width a little closer to given terrain characteristics. Some players (me included) think that it adds flavor to the game and mixes things up a little. This does not mean that it is impractical to create optimized division, they are optimized for a certain situation.

Example - a small Finnish Jäger Division is ideal for the Karelian woods. They are made for that terrain. They would not stand a chance spread out over miles and miles of open field in the steppe.
No-one would burn out a highly mobile division in urban warfare (oh wait, yes some single German leader would...), because it is not made for that terrain.

It is very refreshing that the developers are are mixing things up a little.

And a little "historical nudge" - thinking in categories let the French military botch their defense in 1940. How could the Germans ever do the unthinkable and pass through the impassable Ardenne forest??? ;)
No flexibility there, my friend...
Most infantry units didn't change their OOB too much outside of logistical reasons or equipment/manpower shortages, and most infantry divisions of a country were intended to have the same OOB regardless of where they were sent to. But divisions were also made up of smaller subunits, and as such could be used more flexibly than the game sytem of hoi4 allows, where each division is a single immutable entity. The Germans and Russians didn't decide to completely reorganize their infantry because they pushed forward one province from plains into a forest tile, and they also didn't magically have entire divisions stop fighting effectively just because they got pushed back from a plains tile into a hill tile and forgot to reorganize their division template.

I don't think the new system is any more realistic than the old one.
 
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Most infantry units didn't change their OOB too much outside of logistical reasons or equipment/manpower shortages, and most infantry divisions of a country were intended to have the same OOB regardless of where they were sent to. But divisions were also made up of smaller subunits, and as such could be used more flexibly than the game sytem of hoi4 allows, where each division is a single immutable entity. The Germans and Russians didn't decide to completely reorganize their infantry because they pushed forward one province from plains into a forest tile, and they also didn't magically have entire divisions stop fighting effectively just because they got pushed back from a plains tile into a hill tile and forgot to reorganize their division template.

I don't think the new system is any more realistic than the old one.
I get your point. I still think though that the developers are trying to make an effort at adapting the system.
 
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I get your point. I still think though that the developers are trying to make an effort at adapting the system.
I agree, it is nice to see the devs making an effort. I just think the proposed solution isn't particularly great with what we've been shown so far.

It would have been possible to just change the combat width to encourage something more historical between 20-30w, that would satisfy both the min-maxing players and most of the historical players. In fact, that's what a lot of mods do whose primary selling point is making the game more historically accurate.
 
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It would have been possible to just change the combat width to encourage something more historical between 20-30w,
But that is what they have done. Historical German division being 30w. Design Mountaineer divisions around 25w and that covers over half of the global terrain types.
 
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But that is what they have done. Historical German division being 30w. Design Mountaineer divisions around 25w and that covers over half of the global terrain types.
But not all of them. Hills, forests, and urban provinces are more often than not the most important parts of a country's defensive lines, particularly on the two main European fronts. And neither of those terrain widths can coexist with plains being 30w as showcased so far. It leads to all the problems that have been discussed so far.

The only front I can think of where purely 30w divisions would work is the Egyptian/Libyan front. Every other major front has lots of forests/hills/urban interspersed with plains enough that you won't realistically be able to avoid taking penalties.
 
I just would like to know how you would like to see your idea implemented in doctrine and wanted to make sure that I understand.
You mean having tactics incorporated into doctrines? They already are. Some (including many of the best) tactics require specific doctrines to unlock. You could increase that by having more/all tactics be connected to doctrines, but they'll be reworking doctrine anyway.
 
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Hills, forests, and urban provinces are more often than not the most important parts of a country's defensive lines, particularly on the two main European fronts.
And you should be taking penalties for fighting in this less than ideal terrain. Let's see what they will make those penalties for the update. If they are outrageous, they will be modified.
 
And you should be taking penalties for fighting in this less than ideal terrain. Let's see what they will make those penalties for the update. If they are outrageous, they will be modified.
There are already penalties for fighting in less than ideal terrain. Combat width doesn't have to be one of them, just tune the province modifiers to attack/defense/movement/attrition accordingly.
 
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However the game is designed, I want to be able to optimize my gameplay. The game making itself impractical to optimize is something I disagree with. Every strategy game is just a set of optimization problems at its core. If the game discourages optimization by making it basically impossible, then it's not well designed in my opinion. And when they design different widths that ensure players are taking penalties no matter how they design their troops, that's kind of what they did.
This seems to be a very peculiar variant of the concept of "optimum". "Optimise" means "do the best you can with what is available", not "force or expect every situation to allow 100% effectiveness". If 80% is the best that can be done under a certain set of conditions, then 80% is the optimum. And many circumstances will have multiple, local optima - some of which may even be very similar in their value. Add in the effects of uncertainty and restricted access to information and, while there might, in theory, be an optimum, the usual real life situation is that it's difficult to see and almost impossible to check whether or not you are at. All you really know, most of the time, is whether or not you're currently doing better than the other guy!

Ahistorically, I might add. It's not like IRL a commander would roll in all their divisions' units into range of enemy artillery and then tell 3/4ths of them to take the day off and just wait to be shelled.
For a triangular division structure roughly 80% of the division will be "just waiting to be shelled" at any one time because of the way that reserves usually work. The idea that every weapon of a division fires at once is... just wrong.

The general idea of combat width is pretty necessary to the game. Unfortunately, without making a system which splits divisions and keeps the others' mp/equipment from being affected (or better yet, lets them recover) having combat width like this will make it so that while bad divisions are less bad, it's much harder and less fun to make/use good divisions. I would have massively preferred a tactics rework with (more) terrain-specific tactics, where tactics were more closely connected to doctrine, where they were easier to understand for new players, and they had varied/dynamic effects, such as contributing to breakthrough/defense, or modifying enemy stats.
I'll actually disagree, here, because in Arsenal of Democracy we did it quite differently. Given that formations take up area but fight along a line we made it such that the attack value in a battle was the square root* of the sum of the unit sizes, divided by the total of the unit sizes, times the total attack of all the units. This provides diminishing returns for putting more units into the battle, but no limit - the limit being effectively provided by the logistics.



*: Actually it was a power function close to but not quite square root, for technical/balance reasons.
 
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For a triangular division structure roughly 80% of the division will be "just waiting to be shelled" at any one time because of the way that reserves usually work.
I was referring to the concept that a division "partially" in a battle will still lose equipment like it's fully in the battle, just with less HP (so the effects are worse) in Hoi4. I don't think that IRL reserves "reserved" in the line of fire.
Given that formations take up area but fight along a line we made it such that the attack value in a battle was the square root* of the sum of the unit sizes, divided by the total of the unit sizes, times the total attack of all the units. This provides diminishing returns for putting more units into the battle, but no limit - the limit being effectively provided by the logistics.
I like the "diminishing returns" part but not the massed attacks part. How did attacks interact with defense? Did it just effectively turn battles into one blob vs. another?
I suppose if that's an abstraction of how combat worked irl...
 
Even if they make it so the combat width is guaranteed to be filled so long as you have enough combat width in your divisions to fill it (i.e if you have two 40 width units in a 41 width combat, both will join) then any percentage of your division which is over combat width will be "wasted." You will have put ICs into a division which will be having no impact on the game.
The IC argument only works if you always fight that terrain. If you fight across different terrains (as you usually do), the IC not participating is merely "in reserve".

More importantly, you seem to be repeating the idea that by microing and swapping templates in the field to achieve perfect fit you can somehow gain an advantage / less waste. That is nonsense. If you already have a wider template in the field, then you gain nothing by switching to a narrower template (assuming the over-width penalty is fixed). The equipment goes back into your stockpile but there's no benefit for you compared to the same equipment being on the division. The wider division has more HP so it loses the same amount of equipment, not more.
The IC cost / waste argument is only relevant for how many divisions you can field in total and that is a macro concern not affected by micro.

Let me rephrase: there are 2 reasons to fit perfectly:
1) to avoid having lower total combat performance in the current system (too high over-width penalty) - hopefully this factor is completely removed after this patch
2) to avoid "wasting" IC on the extra width not participating - this still matters on the macro level, but you can't save that IC by changing templates because your divisions are already in the field and paid for. It would only be worth it if one could immediately use it to spawn more smaller divisions in the same spot.
 
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The wider division has more HP so it loses the same amount of equipment, not more.
1k IC division with 100 HP and 100 attack vs 500 IC division with 50 HP and 50 attack
half of the 1k/100/100 division would still be "connected" to the equipment pool of 1k ICs, but only have 50 HP and 50 attacks. Or is the HP not affected? I guess we'll see how it's actually done in the upcoming update lol
either way, i disagree with your argument. let's say that to do a combat a division takes 10 damage (and let's have attacks, damage and hits all be the same). if the 1k/100/100 division hops into a battle halfway, it will do 50 damage at the cost of 10 damage - it just lost (10 dmg/50 HP)*1k = 200 ICs to do 50 damage. meanwhile, the 500/100/100 would only lose 100 ICs to do 50 damage in that situation. so even if they make the overwidth penalty 1%:1% it will still be wasteful to use larger divisions when they don't fit.
as for this:
If you fight across different terrains (as you usually do), the IC not participating is merely "in reserve".
I get what you're saying; eventually, the parts overwidth in some battles will be used in others, so it isn't "in reserve." but that doesn't change the fact that when it is overwidth it's being wasted as it is "in reserve" while exposed to enemy damage. and in a game where, at least against other players, battles are fought for the purpose of depleting enemy ICs this is quite important.
 
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Or is the HP not affected?
HP is not affected, and therefore both divisions in your example lose the same amount of 100 IC to 10 hp damage (20% of HP for the 500IC and 10% for the 1000IC division).
Assuming HP was scaled as well as in your example (it isn't, and they're not likely to change it), I would agree with your argument. But it just isn't the case.
 
HP is not affected, and therefore both divisions in your example lose the same amount of 100 IC to 10 hp damage (20% of HP for the 500IC and 10% for the 1000IC division).
Assuming HP was scaled as well as in your example (it isn't, and they're not likely to change it), I would agree with your argument. But it just isn't the case.
in that case there are other stats to consider, such as being very likely to receive critical hits. but those really can't be discussed until when we see what's in store for targeting and attack dispersion.
 
The more I hear people argue against the width changes the more I like them. I bet, in all of WWII, there was never a situation where a division did not have enough frontage in combat to effectively use all of its strength... I like to minmax but what people are complaining about here is foreign to me. Because a realistic simulation is more important to me than having simple perfect strategies to get the absolute maximum out of every single division.

Worse yet, people are making assumptions about the combat system that has yet to be revealed in their attempt to counter the new changes.

If you want to play a game with perfectly defined moves, I suggest chess, checkers, or perhaps tic tac toe. This is a WWII simulation. I would argue it should be impossible to perfect every combat situation.
 
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