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Europa Universalis IV - Development Diary 24th of May 2022

Hello everyone, Gnivom here today.

I may return for a future dev diary on the many AI improvements we’re making for 1.34, but today’s topic is Land Combat.

First a recap:

For 1.33, we decided to change some things with combat; first mentioned in this January DD and soon amended by making backrow regiments take 60% less morale damage. The core idea was to remove some weird traps that uninitiated players (I would guess a majority) and the AI (without major modifications) would easily fall for. In particular, having a large army without a full back row of artillery could be disastrous.

However, those changes also caused some unintended balance effects:
  1. Battles last longer, sometimes a lot longer.
  2. Morale is much less important.
  3. Stackwipes (officially “overruns”) are much less common (though this is mostly caused by the AI accidentally exploiting the Zombie Regiments bug, by shift-consolidating troops before battle).
  4. Tech Groups’ impact through unit pips have been amplified. This has not been addressed so I won’t mention it again in this DD.
Additionally, some of you have pointed out that what can be seen as a “noob trap” can also be a source of tactical depth in multiplayer.

Now, let's look at what's new for 1.34 and how this addresses these issues.

Passive Morale Damage​

In 1.33 we made the daily 0.03 “morale damage to reserves” actually only apply to reserves, where it previously applied to deployed troops as well. The intention was to relatively penalize overstacking more as well as to be consistent with the name.
This is a major cause for the longer battles in the early game, and for morale being less important, and has now been reworked in 1.34 to as follows:
  • Deployed troops take a daily morale damage of 1% of max morale.
  • Reserves take a daily morale damage of 2% of max morale.
Only the reserves are affected by the Professionalism modifier, so it remains mostly a QoL modifier, although its absolute effect is now much bigger.

Max morale is not based on the regiment itself, but on the average of all regiments on the other side. Such that, in a standoff between a Prussian and a regular soldier, where neither is shooting, the regular soldier will run first.

The fact that this is now a percentage means that its importance will be consistent throughout the ages, so that late-game battle length is now shorter.

While on the subject of morale, some of you may know that when entering a battle against someone with higher morale, your morale progress bar starts at less than 100%. This is now changed to show the percentage of your own average max morale, rather than the max of all regiments on either side. This makes it easier in my experience to guess who is winning from just looking at the bars.

Zombie Regiments​

As mentioned above, EU4 has always had a bug (feature?) called Zombie Regiments.
In 1.34, regiments will always retreat and be replaced once either strength or morale reaches 0, removing the 12 day invincibility.

Additionally, an obscure condition for stack wipes based on the remaining morale of defeated regiments has been removed. You probably didn’t know about it (I didn’t), but it started mattering when 0-strength full-morale regiments were immediately retreated.

All in all, stack wipes are now much more viable than in 1.33, but still less viable than in 1.32 if the losing side has more than a full front row of decent-morale troops.

zombie_wiki.png

Adding a screenshot here for future readers, as the wiki link may be obsolete.

Insufficient Support​

Insufficient Support currently works by applying a flat -25% Military Tactics to all troops of an army that has too much cavalry, even if it’s just 1 knight above the limit. Although it’s made a bit more complicated by counting armies from different countries separately, as well as mercenaries.

In 1.34, this will instead be a scaling penalty of -1% Tactics per percentage point of cav/inf ratio above your limit. The ratio will be calculated based on all deployed front row troops on your side, while the limit will be calculated individually per regiment. Only cavalry gets affected by the penalty.

Two things to note:
  • A country with a high support can still cause allied cavalry to lose Tactics.
  • If you overstack your armies, an overall balance does not guarantee a frontrow balance at every moment of fighting.
Correction: A previous version of this post erroneously talked about "Combat Ability" instead of "Military Tactics"

Artillery Pips​

Artillery unit pips have been rebalanced.
  • Late-game artillery will have less defensive pips and more offensive ones, contributing to shorter late-game battles.
  • Techs 7, 10 and 13; which give two options; now have a distinct difference between the two, where neither is strictly superior to the other.
pips.png

(compare with current values)

Let me take this moment to briefly explain an existing feature: for each damage calculation, backrow artillery propagates half of the sum of relevant defensive pips to the regiment in front of them (rounding down). For example, the Leather Cannon will propagate 2/2=1 pip to strength damage calculation in the fire phase, and 1/2=0 pips during shock phase. For morale damage, it will propagate (2+1)/2=1 pip during the fire phase and (1+1)/2=1 pip during the shock phase.

With this feature in mind:
  • At tech 7, you choose between winning battles quickly (Mortar) or dealing strength damage (Houfnice).
  • At tech 10, the Pedrero is your anti-cavalry weapon by propagating 1 shock defense to the front row. But the Culverin deals more strength damage.
  • At tech 13, the Small Cannon propagates 1 morale defense to the front row in both phases, but the Large Cannon will deal more damage (to both strength and morale).

Reinforcement to Back Row​

This change in particular is still subject to further testing, tweaking and possible removal.

Reinforcement to backrow means something very different now vs in 1.32. In 1.32 it was a way to push further infantry/cavalry into the death pit that was the back row. Only after all inf/cav reserves were spent did artillery reinforce to the back, and once there they never left.
Now (since 1.33) only cannons can be in the back row, and they can also retreat from it, which makes back row reinforcement an important (and positive) thing.

From 1.34, each combat side will be limited to 2 back row reinforcements per day, plus 1 per 2 maneuver pips of the commanding general. This does not limit initial placement of artillery at battle start.

combat_2.png


This is intended to increase tactical depth in multiplayer, by a number of means:
  1. Armies caught low on artillery are more vulnerable, though not as badly as in 1.32.
  2. Cavalry becomes more useful during two distinct phases of the battle:
    1. Just after the initial line of artillery retreat, which happens roughly simultaneously.
    2. Later in the battle, when the combat duration modifier is so high that artillery reinforcements can’t keep up with churn.
  3. This breaks the symmetry of long battles, so that artillery (and by extension, infantry/cavalry as well) don’t all retreat in huge batches.
  4. Quality becomes more important over quantity in long battles, as high quality troops will lower the “artillery saturation” of the enemy.

Breakthrough​

After some initial testing and discussion, this feature will probably not make it into vanilla, but it will be available for modders to enable.
  • Two defines have been created: INFANTRY_BREAKTHROUGH and CAVALRY_BREAKTHROUGH, each being a probability between 0 and 1.
  • When defeating a regiment with artillery behind it, you have a probability (equal to the corresponding define of your regiment) of pulling that artillery into the front row.
If we don’t change our minds, and if you still choose to enable this, there will be no UI or tooltip mentioning this whatsoever.


Well, that’s all for today!

Next week, @Ogele will return with a Dev Diary showcasing the new content we’ve been creating for the first country in the Scandinavian region: Denmark, and its troubled lead over the Kalmar Union.
 

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It's great to see a rework of the battle system because all you have to do was :
-have a bigger army than your war enemy (but not all the time)
-Be sure to have a good morale (too much important)
-Not being late in military tech (shame on you if you have mil tech 6 but all your enemy have 12)
-Optional but important if the enemy have a good one : have a general for bonuses. (and of course for training)
It's good to see there will be some improvement and new features about it !
(I think a rework on the tech might be interresting to see by the way ^^)
 
Changes seems reasonable but ... It looks good on paper.... Just paste the code that we could actually see if it is true t_T . If u wanna make some clash do it with good players not newbie players that are dying to AI on normal t_T
 
I don't think you're going to find a good solution for the combat issues. The combat model is just too simplistic. Changing numbers around will just cause other problems.

Edit: Would really like to see combat much more fleshed out in general. Like in the Field of Glory series for example.
 
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Would you consider adding the option for armies to garrison inside forts for protection? Would add another layer of strategy.
 
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Would you consider adding the option for armies to garrison inside forts for protection? Would add another layer of strategy.
This has remained one of my biggest criticisms of Paradox's combat system, that a fort being sieged is preceded by a "pitched battle" outside the fort, as if all armies were always vulnerable outside the fort/castle upon arrival of enemy troops. For one thing, organized battles would occur from limited excursions outside the fort ("Sally Forth!") - to peck away at the sieging forces, and not just the RNG events that occur as the siege progresses, but possible siege-breaking events from armies that are within layered protection of forts. Speaking of layers, this is one of the other shortfalls in EU4 and PDX's entire combat systems across their games. When a gamer "increases fort level" it's only a metrics increase, but in real-world terms an increased fort would mean yet-more layering of defenses, such as - a second wall around the fort. A 3rd wall. A trench. A secondary trench system. How to account for that? You could camp a good-sized army in these secondary layers outside the core fort/castle defense system, and again - it's a defended position, which then should have standard defense vs offense metrics applied.

In real world military wargaming metrics, a "standard defensive position" on average, with peer/peer military forces opposing one another, works like this -- you must have 3 times the combat power (in metrics) to satisfy taking down a standard defended position. So, all of PDX's games do not follow this real-world construct that military wargaming has used for centuries (dating back to Napoleon and Jomini). If we did have more of this realism applied, sieging would require more planning, and a whole lot more troops, which in real world would incur a logistics bill to even get there (that PDX has also not accounted for - how to feed/sustain/move large formations that miraculously walk across continents with only a "Supply" metric that amounts to a Supply Depot in each province).

Much to unpack here, but PDX actually needs a total overhaul of their combat system, in future PDX games, but it is too late to retool EU4 to this level of change.
 
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This has remained one of my biggest criticisms of Paradox's combat system, that a fort being sieged is preceded by a "pitched battle" outside the fort, as if all armies were always vulnerable outside the fort/castle upon arrival of enemy troops. For one thing, organized battles would occur from limited excursions outside the fort ("Sally Forth!") - to peck away at the sieging forces, and not just the RNG events that occur as the siege progresses, but possible siege-breaking events from armies that are within layered protection of forts. Speaking of layers, this is one of the other shortfalls in EU4 and PDX's entire combat systems across their games. When a gamer "increases fort level" it's only a metrics increase, but in real-world terms an increased fort would mean yet-more layering of defenses, such as - a second wall around the fort. A 3rd wall. A trench. A secondary trench system. How to account for that? You could camp a good-sized army in these secondary layers outside the core fort/castle defense system, and again - it's a defended position, which then should have standard defense vs offense metrics applied.

In real world military wargaming metrics, a "standard defensive position" on average, with peer/peer military forces opposing one another, works like this -- you must have 3 times the combat power (in metrics) to satisfy taking down a standard defended position. So, all of PDX's games do not follow this real-world construct that military wargaming has used for centuries (dating back to Napoleon and Jomini). If we did have more of this realism applied, sieging would require more planning, and a whole lot more troops, which in real world would incur a logistics bill to even get there (that PDX has also not accounted for - how to feed/sustain/move large formations that miraculously walk across continents with only a "Supply" metric that amounts to a Supply Depot in each province).

Much to unpack here, but PDX actually needs a total overhaul of their combat system, in future PDX games, but it is too late to retool EU4 to this level of change.


The other one to add would be to make some sort of national stockpile which ties in to preventing famines caused by war and bad harvests. A mechanic that takes into account a country's development level and how much agricultural goods it produces. This would allow for development to be regulated by technology and at the same time add a logistics system for armies on campaign. Grain, cows, fish, etc.. plus salt (for durability bonuses which would affect trickle rate to simulate waste) would go into a stockpile and population growth (development) growth could be encouraged at the risk of a smaller stockpile for emergencies. The same could be applied to metals and textiles which would be for military gear and transitioning levies that self-provide to a professional army that has standard issued equipment.
 
Pleased to see the zombie unit issue being fixed, and I like that you're looking at improving the rudimentary EU4 combat system but I still think that you're going down the rabbit-hole of 'Nero fiddles while Rome burns' with these changes.

I'm still not convinced that these changes will encourage players to move away from the meta of ditching cavalry for a full back-row of artillery once mil tech 16 is reached. The role of Cavalry evolved massively over the 1444-1821 time period and only became obsolete in WW1. Whilst I don't want to see EU4's combat system evolve into some kind of battle management system, nonetheless Cavalry should be much more impactful that it currently is in the mid-to-late game.

The suggestions by others regarding Cavalry being able to flank the back line is a good one and something I ask you to look at.
 
I like the combat overhaul and the fact that tech group will impact troops more than it does now, I hope you'll add an auto-conversion button because I can't just go in the religious tab and click everytime to convert, especially for one faith.
 
Wow, thanks a lot! Next patch will be very good!


BTW, for focusing on land combat changes much better, I also want some minor changes for naval blockade.

(I know that you are not yet ready to do 'major feature reworks' for now. I won't demand them for a while.
It's just 'minor changes'! trust me. )

Here's my suggestion. Add additional effects to naval blockade.



1. Blockade effects toward the economy of provinces

In current version, the effects of 100% naval blockade toward a province, is this.
  • +20% Local recruitment time
  • +20% Local shipbuilding time
  • +0.1 Monthly devastation
That's not enough. That's almost 90% of the reason why they say naval units in EU4 are useless.

I suggest more effects to 100% naval blockade toward a province, to be like this.
  • +20% Local recruitment time
  • +20% Local shipbuilding time
  • +0.3 Monthly devastation
  • -25% Local goods produced modifier
  • -25% Local trade power

In addition, when the province is an island (second definition), the blockade should have more effects, like this.
  • +50% Local recruitment time
  • +50% Local shipbuilding time
  • +0.5 Monthly devastation
  • -50% Local goods produced modifier
  • -50% Trade value


2. Blockading hostile units & forts

When you 100% blockade enemy provinces, hostile regiments there, will get...

When you blockade an hostile forts (under siege by your regiments), it'll get...
  • +4 Siege bonus for 100% blockade (+1 bonus per 25% blockade)
  • -25% Fort defense (-1% defense per 4% blockade)
 
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"At tech 7, you choose between winning battles quickly (Mortar) or dealing strength damage (Houfnice)."

Do you mean morale damage or casualty damage? Because it sure would be nice if the wording and the meaning were consistent with in game terms
 
From 1.34, each combat side will be limited to 2 back row reinforcements per day, plus 1 per 2 maneuver pips of the commanding general. This does not limit initial placement of artillery at battle start.

What about using similar maneuver-based mechanic for repositioning fighting units at moments when there is no need for reinforcements? For example, cavalry can be moved further to flanks where it can still make damage and don't prevent flanking damage from infantry (like what happens on screenshot below), fix cases of really bad initial unit placement (or when initial placement becomes bad because of arrival of reinforcements/allies), move artillery from front row to back row when there are better units in reserve to hold the line, or just replace damaged front row units with fresh reserves when there is nothing better to do?

I imagine it working in following way: each day army has a "budget" of 2 movements + 1 per 2 maneuver pips of general. This budget can be spent to pull 1 reinforcement, or move 1 unit in combat. Swapping two neighboring units may cost 2 movements, as they both need to move, so by default each army can make 1 swap per day (when not reinforcing).
 

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For example, in this case 0-mandate Ming's infantry in center have taken very heavy losses, while regiments on flanks at full strenght are slacking off.
 

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Wow, thanks a lot! Next patch will be very good!


BTW, for focusing on land combat changes much better, I also want some minor changes for naval blockade.

(I know that you are not yet ready to do 'major feature reworks' for now. I won't demand them for a while.
It's just 'minor changes'! trust me. )

Here's my suggestion. Add additional effects to naval blockade.



1. Blockade effects toward the economy of provinces

In current version, the effects of 100% naval blockade toward a province, is this.

That's not enough. That's almost 90% of the reason why they say naval units in EU4 are useless.

I suggest more effects to 100% naval blockade toward a province, to be like this.


In addition, when the province is an island (second definition), the blockade should have more effects, like this.



2. Blockading hostile units & forts

When you 100% blockade enemy provinces, hostile regiments there, will get...


When you blockade an hostile forts (under siege by your regiments), it'll get...
This is a good improvement because makes fleets more useful. Blockading must damage trade, and maybe Goods produced (but if not, it must damage trade). Good if devs look at it