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HOI4 Dev Diary - News from the Eastern Front

Hi everyone! It’s time to touch base and start talking about what we have been up to since we released 1.6.2. We have been both preparing to start on the next big expansion which will come together with the 1.8 “Husky” Update as well as working on various tasks for 1.7 ‘Hydra’ which is the next upcoming release. Let's jump in. Beware, it’s going to be pretty wordy!

1.7 ‘Hydra’
So first up, why 1.7? This is because we are now going 64-bit which will mean you can no longer run HOI4 on 32-bit, so we want to make it clear it is a different technical base. More on this next dev diary though.
We have also worked on some of the bugs that have popped up since then, most importantly front issues for Germany vs Soviets. This was something that was reported during 1.6.2 development, but as we dug into things it turned out to require a lot more work than we had planned. We made the decision to do it for 1.7, and instead of just fixing that particular issue we also reworked a bit of how fronts and the ai work. This is going to be what the diary will be about today!
Oh and because people will ask... we are not super far away from the 1.7 release. We plan to let you help test it in open beta soon (where soon means like “within a week” or thereabouts).


What’s new on the eastern front?
Operation Barbarossa, which is the German invasion of the Soviet Union, is one of the pivotal balance points in HOI4 (and in all the HOI games) together with the fall of the low countries, Poland and the Sino-Japanese war. After 1.6.2 we had Germany beating the Soviets a bit too easily, and in particular, players had too easy of a time doing it. This had a lot of different reasons. The primary one is that we spent a lot of time overhauling the German strategic and planning AI which has made it very consistent and strong. Additionally for the AI, being good at defending is a much harder job than being good at attacking. What wasn’t working properly was that when the Soviets finally fell, it was often due to an issue related to frontline stability. The Soviet AI would misprioritize this and move a large part of its front elsewhere, leaving a hole that the German AI would often exploit (which players also definitely did). It’s also not fun beating an AI when it makes such a critical mistake. This particular case was extremely random, but the front reaching Crimea was a common factor. At that point, a new front would open at the same time as the line became long enough to require multiple Army Groups to cover it, which was another weakness for the AI. A lot of those technical issues should now behave a lot better and we are consistently seeing much better performance from the Soviets. Although, they do still generally lose in the end, but this is mostly by design.

To explain why this is a good target, let’s look at our balance targets for Barbarossa:
  • The Axis pushes the Soviet line in slowly until the Soviets lose in 1945 unless the Allies secure a big landing and relieve the Soviets, at which point Germany should start losing with its forces split across the 2-3 fronts.
So why is this a good target?
  • As an Axis player, it means business as usual. You get to beat the Soviets, and the better we make the German AI (which does the heavy lifting), the more challenging we can make it for a player Germany and still retain the balance target.
  • As a Comintern player it means you need to defend, hold out, and push back Germany. Here, the stronger we can make the German AI, the more challenging it is for a Soviet player. So to keep our balance target we want to make the Soviet as tough as possible, but on their own, they need to break by ‘45.
  • As an Allied player, you have a bit of a race on your hands. A Germany that has beaten the Soviets will be a very difficult target, so you need to build up your strength and preferably strike when the German army is as extended, as it will get some solid landing points (ai is better at defending too now, so this is not always so easy). From a balance point, we need to make sure that the eastern front holds up long enough for you to get ready to do this. If the Soviets can push back the Germans on their own, there is no reason to play someone on the Allied side. If Germany beats the Soviet too fast, you will not have time to get involved (especially since the Allies are much more spread across the world and contains more minor nations we wanna make sure can make it to the party).
Hopefully, that clarifies how we think about stuff. At the moment the allies do ok in Africa, but pulling off consistent D-Day scale invasions is something we have as more of a long term goal we are working on. Invasion skill for the AI has improved a lot, but the AI has also gotten better at defending. We have thought out a long term plan to also tackle this, but it requires a lot more strategic planning on the side of the AI with respect to theaters, so it is something you will need to look forward to in the future :)

AI in Hearts of Iron is a very complex problem and something we will always be working on improving. It will never really be “done”. We are feeling a lot better about the eastern front now and shuffling issues there, but there is, of course, lots of work left to do everywhere. It won’t fix everything, but I hope it will feel a lot better when you get to try fighting the Soviets again in 1.7 :)

Tools
So while I am talking about AI, let's take a look at some of the tools we use to stay on top of the strategic situation and to help find relevant savegames, etc.

Every night we run several machines hands-off that record various data for us and lets us check whether we broke something, measure improvements, etc. Loading 30 savegames every morning and going over them is neither fun nor effective, so we have developed this awesome web tool that gives us a quick timeline and map to scan over:

Screenshot_1.jpg


Heat maps also make it easy to scan over time and see where the AI is distributing and focusing its units. This example below is highlighting the Japanese forces late 41:

Screenshot_9.jpg


Unit Controller for Players
So that was all about the AI, but we have also done underlying changes as well as UI that will affect you as a player.

A lot of players liked using primarily Army Group Orders for their armies so we have been doing various improvements there. For example, if you do not want to mess with individual army orders on a front you could already hit Shift-Click when setting up the frontline and it would simply keep all the units on the army group order. This is primarily how the AI handles big fronts now. If you do it this way as a player we have cut down a lot of the clutter you get by spreading multiple armies over the same area by having divisions without individual orders and part of an army group order to simply show and group on the map by using the Army Group color. As an example, this is an Army Group Frontline where each army is assigned a piece:

upload_2019-5-15_16-31-1.png

Now, if you are the kind of player who has a big front and wants to simplify things by giving it all over to the Army Group (Shift-Click to create the frontline) you will get this:
upload_2019-5-15_16-31-16.png


There are still 3 armies there, but because you didn’t care to assign a position we won't clutter things by showing that (this also work for garrisoning which is really nice for big areas). You can still select the individual armies as normal in the bottom bar and in the selection lists etc.

For players who prefer to keep control over where each army is assigned we have also made that easier in two important ways:
  • Each army front piece on an army group front must connect, so no holes are allowed. That among other things means that you only need to adjust one point (the connection point) if you want to adjust how much frontline each gets, rather than trying to adjust 2 points, sometimes while the front was moving and with the game unpaused :S
  • We have added controls to be able to change the order of the armies if you want to reshuffle that. The middle of each line when in Edit Mode will now show arrows which let you swap position for that piece of the frontline with its neighbors.
upload_2019-5-15_16-50-51.png


We have also increased saturation on all the rendering of plans on the map to make sure they are easier to see and to make sure they match their respective army colors better.

Next week we will be going over other bugfixes, balance and other changes so tune in then!
 
Who said anything about Operation Sealion?

What I said was this - "then the road would have been open to take Britain prior to Barbarossa."

My argument stands - Britain looses their 224,000 strong professional army at Dunkirk. . . no Churchill speech. . . Luftwaffe destroys RAF. . . England falls

What do you think taking Britain means? It doesn’t mean Britain suing for peace, it means the occupation of the British Isles. Th only way the British are going to accede to a German occupation is if it’s already a reality. That requires Sealion. Sealion has a snowball’s chance in Hell’s sun to succeed.
 
What do you think taking Britain means? It doesn’t mean Britain suing for peace, it means the occupation of the British Isles. Th only way the British are going to accede to a German occupation is if it’s already a reality. That requires Sealion. Sealion has a snowball’s chance in Hell’s sun to succeed.

Think about it instead of digging in and repeating yourself. . .

British government falls. . . Royals go into exile in Canada (like the Dutch,) . . . RAF is destroyed. . . Luftwaffe controls the Channel. . .RN retreats to Canada (Atlantic,) and Australia (Pacific.). . .Way is paved for a puppet/sympathetic government to be put in place in England. . . Britain is taken out of the war.

Who knows, maybe Mosley would be elected in which case the NAZI's would have been invited to Whitehall. . .

That's the beauty of hypothetical. . .
 
Think about it instead of digging in and repeating yourself. . .

British government falls. . . Royals go into exile in Canada (like the Dutch,) . . . RAF is destroyed. . . Luftwaffe controls the Channel. . .RN retreats to Canada (Atlantic,) and Australia (Pacific.). . .Way is paved for a puppet/sympathetic government to be put in place in England. . . Britain is taken out of the war.

Who knows, maybe Mosley would be elected in which case the NAZI's would have been invited to Whitehall. . .

That's the beauty of hypothetical. . .

The Hell? Why are the Royals fleeing? Why would Fascists, who were literally beaten off the streets four years prior, come to power? Why would Mosley ally himself with the Axis? Why is Britain deciding to tear itself apart whenever they could just make peace with a few concessions to Germany? This entire scenario makes no sense. It lacks any basis in reality. The most likely case for a peace with Germany is that Britain accepts German gains on the Continent, recognizes Vichy France, accepts Italy’s annexation of Ethiopia, cedes some Egyptian territory (if that), and calls it a day. The chances of them randomly deciding to ally with the Axis and send the Royal Family into hiding is about as likely as the Communist Japan route.
 
Think about it instead of digging in and repeating yourself. . .

British government falls. . . Royals go into exile in Canada (like the Dutch,) . . . RAF is destroyed. . . Luftwaffe controls the Channel. . .RN retreats to Canada (Atlantic,) and Australia (Pacific.). . .Way is paved for a puppet/sympathetic government to be put in place in England. . . Britain is taken out of the war.

Who knows, maybe Mosley would be elected in which case the NAZI's would have been invited to Whitehall. . .

That's the beauty of hypothetical. . .
Very kaiserreichy indeed :)
 
After Norway, the operational German Navy consisted of exactly 3 cruisers and 4 destroyers. Everything else had been damaged or sunk.

Naval strategy is built strategy -- you can't build a cruiser let alone a carrier in 3 months, especially with Germany's limited shipbuilding capacity.

And that's before looking at logistics needs. In short, Sealion was always impossible.
 
The Soviet Union did not defeat Germany. The big offensives (Bagration, Lvov-Sandomierz, Vistula-Oder etc) that took the Russians from Smolensk to Berlin were possible exclusively because of greater mobility with Lend-Lease trucks and APCs. Six wheel drive Dodge trucks that worked in the rasputitsa and four feet of snow while the Opels sat. (In addition to other massive aid to allow the country to function after GDP was halved from 1940-42)

The story of both world wars is America defeating Germany.
 
The game to be really balanced should limit the number of battalions a country can build, the number of airplanes that can be flown at a given point in time and the number of ships able to float at the same time. These numbers should not be based on manpower or factory capacity but on leadership available. HOI 3 had it right when you had to choose on how much you could research versus how many leaders you could dedicate to the armed forces. Build all the equipment you want but without leadership, none of it makes it to the front.
 
There’s a huge, huge, HUGE difference between Britain asking for peace and the Nazis invading Britain successfully. Britain’s political establishment throwing in the towel is somewhat plausible, their military absolutely failing to stop a vastly inferior force who’s naval heyday was over twenty years past and who lack the naval logistics to actually support any resisted invasion is not.

It was very probable that the British would have attempted to negotiate some limited surrender to the Axis. Ultimately, forcing the British to the negotiating table was also the Nazis goal as well, as the Nazis never intended to fight the West, their long term goal had always been to conquer the Soviet Union. Really the only way that peace would have failed is if the negotiations failed, and, in this hypothetical scenario, neither side could really afford to let them fail.
 
Please fix Air UI.
 
we are consistently seeing much better performance from the Soviets. Although, they do still generally lose in the end, but this is mostly by design.

To explain why this is a good target, let’s look at our balance targets for Barbarossa:
  • The Axis pushes the Soviet line in slowly until the Soviets lose in 1945 unless the Allies secure a big landing and relieve the Soviets, at which point Germany should start losing with its forces split across the 2-3 fronts.


I'm sorry, but this is just ridiculous. Is this game dropping all its pretense at historicity? I mean with all the focus on the alt-history trees it was kind of clear, but at least you could disable them. And this now is way too much.

Historically, by the time D-Day happened, the USSR has already decisivly turned the tides. The USSR has already been outproducing Germany and outmatching Germany in fielded manpower and equipment for quite some time by that moment. After the Kursk battle of summer 1943 (almost a year prior to the D-Day!) Germany was not able to regain initiative and go into offence for the rest of the war even once.The D-Day only hastened the fall of Germany, but was in no way decisive to this outcome (well, it was decisive with respect to the zones of control distribution after the war).

Why then don't you balance the game in a way that Japan defeats the USA in the Pacific in most games, and launches an invasion of California? It'd be even more fun from the balance point of view.

I strongly believe that the game by default should be balanced in a way that in most games we should see developments resembling the historical ones, if you play "Historical". The people who want to see e.g. a stronger Germany have the "Strengthen Germany" slider in their hands.
 
I strongly believe that the game by default should be balanced in a way that in most games we should see developments resembling the historical ones, if you play "Historical". The people who want to see e.g. a stronger Germany have the "Strengthen Germany" slider in their hands.

What you're asking is impossible from a gameplay perspective. Take into account that the historical developments in Europe happened due to serious mistakes made by the Allied/Soviet high command, but that it's not something that you can really represent in a game.

For example, if you make the Soviets strong enough to beat the Axis without the Allies opening a second front playing as either Germany or an Allied power will feel unrewarding as the first cannot win the game and the second it's unnecessary in the conflict after 1941.

The real game balance here that Germany is able to push the Soviets and have a real chance of winning but normally it would be defeated as it has to face multiple fronts.
 
It’s a balance thing. That was explicitly mentioned.



100,000 men is 100,000 men, whether or not they’re on the Eastern Front or in Africa. That’s still several divisions worth of soldiers that could hold Stalingrad’s flanks or support a drive into the Caucasus. Trying to go “It’s but a drop in the ocean” only ignores how influential smaller forces can be. If the destruction of 250,000 men can be considered a crippling disaster, there’s no reason 100,000 men can’t be considered a significant threat.


The Germans had over 100k men stationed in Norway doing nothing the entire war.
 
Thanks for DD!

Although, they do still generally lose in the end, but this is mostly by design.

To explain why this is a good target, let’s look at our balance targets for Barbarossa:
  • The Axis pushes the Soviet line in slowly until the Soviets lose in 1945 unless the Allies secure a big landing and relieve the Soviets, at which point Germany should start losing with its forces split across the 2-3 fronts.

For me, this is the best solution balance-wise. From a historical plausibility it's disputable at least. I doubt it was "D-Day what spared Soviets from an inevitable defeat", but rather some Allied involvement for the whole war. But, again, for me it's fine as long as Soviets don't fold like house of cards in the first weeks of Barbarossa.

  • As an Axis player, it means business as usual. You get to beat the Soviets, and the better we make the German AI (which does the heavy lifting), the more challenging we can make it for a player Germany and still retain the balance target.

I'm a bit worried about the point above. Why don't treat all AI equal? I want a challenging opponents even if I don't fight against Reich.
 
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What's the point of a game that just goes historically?

That's not a game that's a cutscene.
 
So are PDX et al basically stating that lend-lease was irrelevant?

So if i am the USA player and I pump SOV with materiel it doesnt matter as they will lose anyway?

Anyway, anyone with even the remotest understanding of basic WW2 knowledge knows that everything other than the Eastern Front was a sideshow.
German output in 1944 was greater than 1941- this is despite the 'crippling' allied bombing runs.
El Alamein was irrelevant- even if Germany won in North Africa- how would they get any oil across the Med? Rommel was constantly undersupplied and unsupported by German high command- the North Africa campaign was for politcal reasons to shore up the continual embarrassment that was Italy.
Lend lease had no effect on the two critical Soviet Defensive victories Moscow and Stalingrad. Lend lease was however crucial for the speed of the offensive victories in 1944-45.

Kursk was doomed from the start regardless of what was happening in Italy- partially due to allied intelligence sharing (which is not even present in the game yet)

I strongly advise anyone hasn't already to compare D-Day to Operation Bagration which occur at almost the same time.

We all know that D-Day was delayed as long as possible and all it achieved was to protect Western Europe from becoming SSR's.
If D-Day occurred in summer 1943 then it would be considered a turning point, but by summer 1944 the Axis were in a death spiral.

Back to the game- the default position should be a SOV victory but it should take 1 year longer without Allied landings and 2 years longer without lend lease This should be overcome with sliders.
The game should incorporate a ratio between war support and defeat progress ie if war support is high, defence should increase exponentially as defeat progress increases. This would prolong the eastern front to its maximum.
 
Ah, finally another flame war over who defeated the nazis "in reality". As a german, to my mind, the Soviet Union deserves the greatest credit in terms of military warfare, the US deserves the greatest credit in terms of economical warfare, and the British deserve the most credit in terms of ideology and diplomacy. If you took any of the big three, Roosevelt, Stalin and Churchill, out of the equation the war would have developed way more in Hitlers favour - allthough it remains disputable wether Germany could have won the scenario under different circumstances - with Hitler at the top of the chain of command in military, economy and diplomacy.

To my mind, Hitler himself also deserves a lot of credit for defeating Germany. Not only was he the guy who pulled the trigger on Hitler, he was also totally inept in terms of diplomacy, warfare and economy, and arrogant enough not to care the slightest way about that.

Hitler's arrogance and incompetence probably killed as many germans as the Red Army, the Royal Navy and the US Air Force combined, so when it comes to putting credit where its due, for me, it certainly is the austrian who is the most underappreciated in this whole equation.
 
The Soviet Union did not defeat Germany. The big offensives (Bagration, Lvov-Sandomierz, Vistula-Oder etc) that took the Russians from Smolensk to Berlin were possible exclusively because of greater mobility with Lend-Lease trucks and APCs. Six wheel drive Dodge trucks that worked in the rasputitsa and four feet of snow while the Opels sat. (In addition to other massive aid to allow the country to function after GDP was halved from 1940-42)

The story of both world wars is America defeating Germany.
Goodfellas-Hilarious-laugh.jpg

goodfellas-hilarious-laugh
 
Ah, finally another flame war over who defeated the nazis "in reality". As a german, to my mind, the Soviet Union deserves the greatest credit in terms of military warfare, the US deserves the greatest credit in terms of economical warfare, and the British deserve the most credit in terms of ideology and diplomacy. If you took any of the big three, Roosevelt, Stalin and Churchill, out of the equation the war would have developed way more in Hitlers favour - allthough it remains disputable wether Germany could have won the scenario under different circumstances - with Hitler at the top of the chain of command in military, economy and diplomacy.

To my mind, Hitler himself also deserves a lot of credit for defeating Germany. Not only was he the guy who pulled the trigger on Hitler, he was also totally inept in terms of diplomacy, warfare and economy, and arrogant enough not to care the slightest way about that.

Hitler's arrogance and incompetence probably killed as many Germans as the Red Army, the Royal Navy and the US Air Force combined, so when it comes to putting credit where its due, for me, it certainly is the austrian who is the most underappreciated in this whole equation.


The biggest difference between Stalin and Hitler at least in the books I have read, is that the more things went wrong, the more Hitler took over. Stalin on the otherhand took more of back seat when things were going wrong, the STAVKA was really a committee between 1942-44 and Stalin was regularly talked out of different strategies by Zhukov, even shouted at.
 
Awesome news! Good to hear the frontline problems will be solved soon!
Took some time, but better a solid and well designed solution that takes time than a quick and dirty solution.
Pretty interesting. I can imagine how difficult and challanging the whole AI topic in HOI is, and I am impressed about your results how to balance such a complex simulation.
Thanks so much for your amazing work and in-depth explanations ans insights, devs!

PS: I am organizing a small private HOI4 LAN party with 2 friends, so I am very optimistic we have the patch (at least beta) until then! Just in time! ;)
 
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What you're asking is impossible from a gameplay perspective. Take into account that the historical developments in Europe happened due to serious mistakes made by the Allied/Soviet high command, but that it's not something that you can really represent in a game.

For example, if you make the Soviets strong enough to beat the Axis without the Allies opening a second front playing as either Germany or an Allied power will feel unrewarding as the first cannot win the game and the second it's unnecessary in the conflict after 1941.

The real game balance here that Germany is able to push the Soviets and have a real chance of winning but normally it would be defeated as it has to face multiple fronts.


Like I said, then why don't they balance the game in a way where Japan would defeat the USA in the Pacific in most games? It would be even more interesting from the gameplay perspective, would it not?

The North African Campaign was happening at the same time as Stalingrad. The North African Campaign resulted in the Axis losing almost 500,000 men. Maybe the 6th army wouldn't have been encircled if there was a few 100,000 more troops on the eastern front.

https://en.wikipedia.org/wiki/North_African_Campaign

You do realize that even if we accept this highly speculative reasoning, your argument does not in any way support the decision to balance the game such that
The Axis pushes the Soviet line in slowly until the Soviets lose in 1945 unless the Allies secure a big landing
If it's the agrument that you have, why don't you balance the game in a way that "The Axis pushes the Soviet line in slowly until the Soviets lose in 1945 unless the Allies put up a fight in North Africa"?