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HoI4 Dev Diary - Officer Corps Recap & AI Improvements

Hi all, and welcome back to today’s developer diary!

It can be very easy to get super-focused on details when looking at individual systems or parts of features - something we often tend to do when writing developer diaries. Each week, we’re going to give you an overview of a core system that we’ve so far introduced in parts, and will include all of the changes we’ve made to that system over the course of development, since we first looked at it.

In addition to this, we’ll also take a look at some changes coming to the AI in No Step Back, so if that’s more your jam, feel free to skip to the end ;D

We’ll begin with an overview of the Officer Corps:

0.png

This image represents a near-final take on what the office corps screen will look like.

As you can see, the branch chiefs, theorist, and military high command have found their way to the officer corps screen, though for ease of access you may still view and appoint them in the country overview screen like before. This kind of change is the sort of thing that comes up during playtesting - while it made sense to collect similar things together, there was no good reason to change the player’s flow expectations.

The manner in which you’ll appoint advisors has changed a bit. We decided during the officer corps development process, to make a bigger deal out of the advisor ‘level’ (specialist, expert, genius) that all non-theorist advisors possess. In addition to adding a flat command power allocation (reduction of max command power) which is reduced by high advisor ranks, political power costs are raised by having a higher rank advisor.

Branch advisors now grant daily experience gain, meaning stacking your command cadre well is vitally important to the pre-war development of your military. To add to the choices, doctrines now cost experience rather than being something you spend a research line on:

1.png


For owners of No Step Back, military branches also possess several specialization options in the form of Military Spirits, which are also unlocked with experience:

2.png


We found during development that less was more when it came to creating a tightly balanced set of choices, and we’ve limited the number of options in each category to around six, with each category being strongly themed around Academy, Military Service, and Command.

To add slightly more nuance to choices here, we ensured that several options in each category would be made available based on situational factors - ideology, doctrine branch, and in rare cases, country choice, can all make new choices available.

The most important part of cultivating a strong officer corps, is the ability to give your trusted commanders advisory roles. Commander traits earned in active combat can make your characters eligible for specific advisory roles:

3.png


Characters promoted to advisory duties this way will continue to advance their advisory rank as their commander level increases - a highly experienced field commander will grow from specialist to genius over the course of their career.

Lastly, we are introducing the preferred tactics weighting system. This allows you to set a national, field marshal, and commander-level preferred tactic, which will weight the chances of picking said tactic in a combat situation. While the national preferred tactic can be switched out for a cost, selecting a preferred tactic for your commanders and field marshals is something that remains a permanent choice, representing their adherence to a particular doctrinal theory.

Of course, a host of minor changes accompany the officer corps, including new alerts, better resource tooltips, and adding some of this information into intel ledgers for opponent countries.

The AI

And now, on to a topic that is sure not to evoke strong opinions from anybody here: the AI.

During the development of La Resistance, work was begun on adding additional tools through an imgui that allow modders and users to see various internal data. In NSB, a significant amount of time was spent adding to this tooling and providing support for future AI development, as well as laying the groundwork for easier iteration on AI behaviour and more.

4.png

One of our new in-game tools for assessing AI font priorities. These tools will be available for modders, who can continue to fine-tune AI for their own needs through the use of strategies and defines. Here, you can see that the AI has evaluated the topmost defense order as desiring a minimum of 7 divisions, an 'ideal' count of 8, and a maximum count of 50. Defense orders tend to fluctuate quite heavily in 'ideal' unit counts: they tend to be quite elastic to make up for units not needed elsewhere.

While much of the work done here was investment for the future, we’ve also made some pretty big changes to the way the AI evaluates where it commits its troops and more.

While it can be hard to indicate objective improvements in terms of AI, there are several key areas we aimed to improve for this release:

Use of specialized divisions - the AI for assigning armor and special forces to appropriate fronts has received some improvement. The practical upshot of this means you ought to see fewer armor divisions assigned to inappropriate orders (garrisons, pure defensive lines etc), and mountaineers used in frontlines that have the right terrain types.

5.png

Did I mention the AI likes tanks?

Unit weight distribution - combined with the new supply system, the AI evaluation of where to put units has been totally overhauled. In practical terms, this is likely to manifest as seeing the AI commit more troops to defend key areas (ports & coasts), care more about the active supply situation on frontlines, and provide something slightly resembling a defense in depth for their own core territory, even during active frontline pushes elsewhere.


6.png


You can see that the AI considers supply carefully when assessing front unit distribution. There are certain circumstances in which the logical supply capacity of a front can be exceeded by the AI - notably when a defensive frontline is facing a numerically superior foe, or when the AI determines that it needs to win a war fast.

7.png

Once Moscow has fallen, the supply situation can get pretty dire as you push east.

Naval Invasions - logic for AI naval invasions has seen significant improvement. You should be encountering larger, less frequent naval invasions overall. The Ai will try to take advantage of weak points in coastal defences, and generally be more keen to invade to support theaters. This got so scary we had to turn the new capabilities down several times (of course, these can be tuned back up).

Counters - while it can be difficult to determine a ‘right’ time to switch templates or create a specialized template, we’ve improved logic for majors utilizing specialized divisions such as Tank Destroyers in relevant circumstances. You should see the AI care a little more about what you throw at it.

Buffer Fronts - Several AI strategies now involve the use of buffer fronts. These are specially defined area defense orders which will request a proportion of national divisions to man them. Where these differ from regular garrison orders, is that these fronts will ‘loan’ their unit distribution counts to nearby fronts or invasion orders.

For example, the heatmap below show the distribution of US troops several months prior to Overlord. The troops stationed in Alexandria and the UK are using buffer fronts, which will supply frontlines in europe, in order to avoid having to relocate troops from much further away. Here you can see the (somewhat anachronistic) defense of Greek territory being supplied by the buffer front in Alexandria, which is in turn supplied with divisions from the US mainland (arriving through the Mediterranean).


8.png

The locations and weightings of these are instructional only.
 
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Yes and that's part of the problem there is no unique specialization to them thus allowing ridiculous numbers of planes to be fielded with minimal or no detractors.

Yes, and I'm fairly sure that's what @dcalpanda would like to have changed.

It's also not a thing I believe PDX will ever do in HoI4, since doing so goes away from the simplified design philosophy they've followed for most of HoI4's systems.
Exactly. With this change it would make the player use their air force in a more tactical way. Maybe they wont do it but I dont think it would impact things too much. We already have a manpower pool. There was just be a sub pool that is just for pilots. Maybe you can spend cp to increase the rate at which pilots are trained for X amount of time. IDK just a suggestion.
 
Exactly. With this change it would make the player use their air force in a more tactical way. Maybe they wont do it but I dont think it would impact things too much. We already have a manpower pool. There was just be a sub pool that is just for pilots. Maybe you can spend cp to increase the rate at which pilots are trained for X amount of time. IDK just a suggestion.
I like your idea of a pilot pool, but using CP is not something I would recommend.

The real life main constraints to a pilot pool were 1) the fuel it took to train them, 2) time, and 3) the number of planes trainees and new pilots crashed. I would make the game's pilot training program reflect that. It would be more realistic and some of the tools are already there.

For example, the player could access the pilot pool, via a UI window, assign some manpower to it, select what planes he is willing to let the trainees consume, and choose how fast or slow he wants the pilots to train. This speed of training is important. The United States was willing to lose tens of thousands of aircraft and unlimited fuel to train its pilots very fast, like six or seven months. The Germans, up until about 1942, spent about thirteen months to train pilots, but they lost much fewer planes doing it. By 1944 the British were spending almost two years training pilots, but losing even less aircraft doing it.

For game purposes, it has to be simplified and abstracted, but fuel, time, and crashing aircraft are already in the game. While nothing is easy in making a game, at least a pilot pool can use some of the functions/tools already in the game.
 
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I've been looking at the new officer corps system and it has generated a few questions. Overall, I think it is a welcome addition.

1. Does the theorist generate xp do we know?
2. Is the advisor rank directly linked to field officer rank? If so, then most field officers will start at specialist. Rommel is a genius so I don't expect him to start at level 8 rank? Or will he?
3. If advisor rank is linked directly to field rank then this system will still favour combat roles and countries which engage in more warfare. Perhaps a small amount of experience to level up should be given for being an advisor? This would also benefit the advisors without a field officer avatar. You'd expect the head of your army, navy or airforce to learn something after years of warfare.
 
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I like your idea of a pilot pool, but using CP is not something I would recommend.

The real life main constraints to a pilot pool were 1) the fuel it took to train them, 2) time, and 3) the number of planes trainees and new pilots crashed. I would make the game's pilot training program reflect that. It would be more realistic and some of the tools are already there.

For example, the player could access the pilot pool, via a UI window, assign some manpower to it, select what planes he is willing to let the trainees consume, and choose how fast or slow he wants the pilots to train. This speed of training is important. The United States was willing to lose tens of thousands of aircraft and unlimited fuel to train its pilots very fast, like six or seven months. The Germans, up until about 1942, spent about thirteen months to train pilots, but they lost much fewer planes doing it. By 1944 the British were spending almost two years training pilots, but losing even less aircraft doing it.

For game purposes, it has to be simplified and abstracted, but fuel, time, and crashing aircraft are already in the game. While nothing is easy in making a game, at least a pilot pool can use some of the functions/tools already in the game.


I like your suggestion and since these mechanics already exist in the game, I hope it can be added some day. In a perfect world, in NSB.
 
Good Questions LostinSpice and I like them.

1. I don´t know, but I think so. For what we have the Theoreticans? Not only for giving us a Bonus with new R & D-Thinks.

2. and 3. From what I have read, all can be Advisors with a normal General-Rank and work it up too like they were in Fieldtraining or War. From what I have seen in the Dev Dirays too that the Command-Staff / Advisors give XP too (like Student, Dönitz, Bey etc.) with more XP-Gaining and better use of the Combat-Things later on.

Short said: We will see how good everything works. It´s already in the Game, but can´t fully used with the existing System. The Refit is a good Chance to link everything together and we have to experiment with it after it comes out. If we get lucky an Gameplay-Vid will be presentet or it comes in the Tutorial-Vids.
 
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@Arheo

Great dev diary! :)

Will your team's efforts to improve the AI for NO Step Back include revising the AI area id's for Northern Epirus provinces 13234 and 13235? These 2 provinces currently show as AI area id's 3-north america. I believe that the ai area id's should be 2-europe. Please reference bug report 1495030 issued today.
 
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@Arheo

Just to put it out there, Would adding a Pilot pool be in the plans ever for HOI?

just to quote a good post for reference.


I like your idea of a pilot pool, but using CP is not something I would recommend.

The real life main constraints to a pilot pool were 1) the fuel it took to train them, 2) time, and 3) the number of planes trainees and new pilots crashed. I would make the game's pilot training program reflect that. It would be more realistic and some of the tools are already there.

For example, the player could access the pilot pool, via a UI window, assign some manpower to it, select what planes he is willing to let the trainees consume, and choose how fast or slow he wants the pilots to train. This speed of training is important. The United States was willing to lose tens of thousands of aircraft and unlimited fuel to train its pilots very fast, like six or seven months. The Germans, up until about 1942, spent about thirteen months to train pilots, but they lost much fewer planes doing it. By 1944 the British were spending almost two years training pilots, but losing even less aircraft doing it.

For game purposes, it has to be simplified and abstracted, but fuel, time, and crashing aircraft are already in the game. While nothing is easy in making a game, at least a pilot pool can use some of the functions/tools already in the game.


Great dev diary !
 
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The real life main constraints to a pilot pool were 1) the fuel it took to train them, 2) time, and 3) the number of planes trainees and new pilots crashed. I would make the game's pilot training program reflect that. It would be more realistic and some of the tools are already there.
I'd argue that all off the tools are there.

This speed of training is important. The United States was willing to lose tens of thousands of aircraft and unlimited fuel to train its pilots very fast, like six or seven months. The Germans, up until about 1942, spent about thirteen months to train pilots, but they lost much fewer planes doing it. By 1944 the British were spending almost two years training pilots, but losing even less aircraft doing it.
Can you provide a source for those training times? I came up with nine (9) months for training, but that is probably biased from US sources. I'm wondering if maybe 12 months wouldn't be more appropriate, with the US getting a spirit to reduce the training time (and increasing the accident rate)? 2 years for the Brits? Assume it is because of late war conditions, more of an exception than the norm.
 
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Can you provide a source for those training times? I came up with nine (9) months for training, but that is probably biased from US sources. I'm wondering if maybe 12 months wouldn't be more appropriate, with the US getting a spirit to reduce the training time (and increasing the accident rate)? 2 years for the Brits? Assume it is because of late war conditions, more of an exception than the norm.
I just did quick Googles for the post so to have something to start the discussion with.

For the RAF I saw this:

RAF Museum

It has the following paragraph on the first web page describing RAF training times:

"The time taken to qualify as a pilot could vary. At the start of the war it could be as little as six months (150 flying hours). On average it took between 18 months to two years (200-320 flying hours)."


For the US I saw several sites, but here is one:

National Museum of US Air Force
It has the following paragraph on the first web page:

Flight Training Aircraft
At the beginning of the war, flight training lasted nine months, with three months of primary, three months of basic, and three months of advanced training. Each pilot had 65 flying hours of primary training and 75 hours of both basic and advanced training. During the war, each phase was reduced first to 10 weeks and then to nine weeks. Primary training was accomplished in aircraft such as the PT-17, PT-19, PT-22 and PT-23 while basic training took place in mostly in the BT-9, BT-13, BT-14 and BT-15. Advanced training for fighter pilots took place in the AT-6, and training for multi-engine aircraft occurred in the AT-9 and AT-10 aircraft. The AT-11 was used to train bombardiers and navigators.

As you can see, it started off as nine months, but go truncated from three x three month sessions to three x 9 weeks, which is 27 weeks.

I am sure there are much better sources. This was just what I found with a quick glance.
 
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Hi all, and welcome back to today’s developer diary!

It can be very easy to get super-focused on details when looking at individual systems or parts of features - something we often tend to do when writing developer diaries. Each week, we’re going to give you an overview of a core system that we’ve so far introduced in parts, and will include all of the changes we’ve made to that system over the course of development, since we first looked at it.

In addition to this, we’ll also take a look at some changes coming to the AI in No Step Back, so if that’s more your jam, feel free to skip to the end ;D

We’ll begin with an overview of the Officer Corps:

View attachment 764652
This image represents a near-final take on what the office corps screen will look like.

As you can see, the branch chiefs, theorist, and military high command have found their way to the officer corps screen, though for ease of access you may still view and appoint them in the country overview screen like before. This kind of change is the sort of thing that comes up during playtesting - while it made sense to collect similar things together, there was no good reason to change the player’s flow expectations.

The manner in which you’ll appoint advisors has changed a bit. We decided during the officer corps development process, to make a bigger deal out of the advisor ‘level’ (specialist, expert, genius) that all non-theorist advisors possess. In addition to adding a flat command power allocation (reduction of max command power) which is reduced by high advisor ranks, political power costs are raised by having a higher rank advisor.

Branch advisors now grant daily experience gain, meaning stacking your command cadre well is vitally important to the pre-war development of your military. To add to the choices, doctrines now cost experience rather than being something you spend a research line on:

View attachment 764653

For owners of No Step Back, military branches also possess several specialization options in the form of Military Spirits, which are also unlocked with experience:

View attachment 764654

We found during development that less was more when it came to creating a tightly balanced set of choices, and we’ve limited the number of options in each category to around six, with each category being strongly themed around Academy, Military Service, and Command.

To add slightly more nuance to choices here, we ensured that several options in each category would be made available based on situational factors - ideology, doctrine branch, and in rare cases, country choice, can all make new choices available.

The most important part of cultivating a strong officer corps, is the ability to give your trusted commanders advisory roles. Commander traits earned in active combat can make your characters eligible for specific advisory roles:

View attachment 764655

Characters promoted to advisory duties this way will continue to advance their advisory rank as their commander level increases - a highly experienced field commander will grow from specialist to genius over the course of their career.

Lastly, we are introducing the preferred tactics weighting system. This allows you to set a national, field marshal, and commander-level preferred tactic, which will weight the chances of picking said tactic in a combat situation. While the national preferred tactic can be switched out for a cost, selecting a preferred tactic for your commanders and field marshals is something that remains a permanent choice, representing their adherence to a particular doctrinal theory.

Of course, a host of minor changes accompany the officer corps, including new alerts, better resource tooltips, and adding some of this information into intel ledgers for opponent countries.

The AI

And now, on to a topic that is sure not to evoke strong opinions from anybody here: the AI.

During the development of La Resistance, work was begun on adding additional tools through an imgui that allow modders and users to see various internal data. In NSB, a significant amount of time was spent adding to this tooling and providing support for future AI development, as well as laying the groundwork for easier iteration on AI behaviour and more.

View attachment 764656
One of our new in-game tools for assessing AI font priorities. These tools will be available for modders, who can continue to fine-tune AI for their own needs through the use of strategies and defines. Here, you can see that the AI has evaluated the topmost defense order as desiring a minimum of 7 divisions, an 'ideal' count of 8, and a maximum count of 50. Defense orders tend to fluctuate quite heavily in 'ideal' unit counts: they tend to be quite elastic to make up for units not needed elsewhere.

While much of the work done here was investment for the future, we’ve also made some pretty big changes to the way the AI evaluates where it commits its troops and more.

While it can be hard to indicate objective improvements in terms of AI, there are several key areas we aimed to improve for this release:

Use of specialized divisions - the AI for assigning armor and special forces to appropriate fronts has received some improvement. The practical upshot of this means you ought to see fewer armor divisions assigned to inappropriate orders (garrisons, pure defensive lines etc), and mountaineers used in frontlines that have the right terrain types.

View attachment 764657
Did I mention the AI likes tanks?

Unit weight distribution - combined with the new supply system, the AI evaluation of where to put units has been totally overhauled. In practical terms, this is likely to manifest as seeing the AI commit more troops to defend key areas (ports & coasts), care more about the active supply situation on frontlines, and provide something slightly resembling a defense in depth for their own core territory, even during active frontline pushes elsewhere.


View attachment 764658

You can see that the AI considers supply carefully when assessing front unit distribution. There are certain circumstances in which the logical supply capacity of a front can be exceeded by the AI - notably when a defensive frontline is facing a numerically superior foe, or when the AI determines that it needs to win a war fast.

View attachment 764659
Once Moscow has fallen, the supply situation can get pretty dire as you push east.

Naval Invasions - logic for AI naval invasions has seen significant improvement. You should be encountering larger, less frequent naval invasions overall. The Ai will try to take advantage of weak points in coastal defences, and generally be more keen to invade to support theaters. This got so scary we had to turn the new capabilities down several times (of course, these can be tuned back up).

Counters - while it can be difficult to determine a ‘right’ time to switch templates or create a specialized template, we’ve improved logic for majors utilizing specialized divisions such as Tank Destroyers in relevant circumstances. You should see the AI care a little more about what you throw at it.

Buffer Fronts - Several AI strategies now involve the use of buffer fronts. These are specially defined area defense orders which will request a proportion of national divisions to man them. Where these differ from regular garrison orders, is that these fronts will ‘loan’ their unit distribution counts to nearby fronts or invasion orders.

For example, the heatmap below show the distribution of US troops several months prior to Overlord. The troops stationed in Alexandria and the UK are using buffer fronts, which will supply frontlines in europe, in order to avoid having to relocate troops from much further away. Here you can see the (somewhat anachronistic) defense of Greek territory being supplied by the buffer front in Alexandria, which is in turn supplied with divisions from the US mainland (arriving through the Mediterranean).


View attachment 764660
The locations and weightings of these are instructional only.
Really liking the way this is going. :)
 
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The real life main constraints to a pilot pool were 1) the fuel it took to train them, 2) time, and 3) the number of planes trainees and new pilots crashed. I would make the game's pilot training program reflect that. It would be more realistic and some of the tools are already there.
IMO, the simplest way to, if not solve this, at least improve it would be to increase the pilot training time and significantly increase the accident rate for untrained pilots. Plus, accidents should result in reduction of squadron experience, not just equipment, the same way casualties do for land units. Because sometimes accidents are fatal! We know from WWII how highly effective Japanese carrier pilots were in 1940-42 - because they had spent years training both individual flight skills as well as squadron and air group tactics and coordination. And we know how poorly they performed in 1944-45 precisely because they didn't have the time or the fuel to train.
 
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@Arheo just a quick question about the AI stuff you've taked about here, in particular about having to turn down the scariness of naval invasions etc (and presumably other elements). Can this/will this be implemented as a factor in the difficulty settings for the AI in a given game? E.g. lower difficulties tone it down, harder difficulties tone it up... this might prove more challenging for experienced players than just a production/research bonus/malus, and also give newer players an option too.
 
@Arheo just a quick question about the AI stuff you've taked about here, in particular about having to turn down the scariness of naval invasions etc (and presumably other elements). Can this/will this be implemented as a factor in the difficulty settings for the AI in a given game? E.g. lower difficulties tone it down, harder difficulties tone it up... this might prove more challenging for experienced players than just a production/research bonus/malus, and also give newer players an option too.
It can be scary for AI too. Eg. Japan has tuned down landings in China