HOI4 Dev Diary - Early look at at supply and the coming year

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podcat

Game Director <unannounced>
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Hi everyone and welcome back to regular weekly dev diaries (if you don't count the april fools one last week). I know you are all super excited to hear what we have been up to since Battle for the Bosporus. The answers to that are going to take a few dev diaries to cover, so I figured I would start with a timeline for you:
  • We recently released 1.10.4 to fix various multiplayer exploits going on, but seems an important case was not detected at the time so we are working on a 1.10.5 to address that soon.
  • Pdxcon is coming up in May so expect to hear some more details there.
  • The yearly anniversary is coming in June so expect some cool stuff and a patch.
  • We are however spending most of our time on the 1.11 Barbarossa update as well as the unannounced expansion that will be released together with it. That's what we will spend most of our diaries on, as well as today!

‘Barbarossa’ and the unannounced DLC will focus on the Eastern Front and the core of Hearts of Iron, which is warfare - particularly land warfare. Historically the Eastern Front was without doubt the most important front for World War II. It was the largest confrontation in history and
is where Hitler’s expansion was first stopped and pushed back signaling the eventual doom of the axis powers. There are several areas we want to improve here. Weather does not feel impactful enough, while historically it had a massive impact. Logistics currently doesn’t have much player interaction and is mostly something you have to deal with only when problems appear, and finally the combat and division meta has been stable (with an emphasis on large divisions) for a long time - something we hope we can shake up. As you can imagine, these are all things that affect the game on a deeper level and take a lot of work to get right.

Today, I’ll give you guys a bit of an overview on the supply aspect, but fair warning: it’s early days and stuff may still change here before we’re done. I’ll probably spend 3+ diaries on supply over the course of the development to cover everything, but I figured it would be nice to hear about the overarching ideas.

The old system worked by having discrete supply areas pathing back to the players capital and keeping track of the bottlenecks. To simplify a bit ;) - those bottlenecks then decided how many units could fit into areas near the front without penalties. The areas themselves were unintuitive to players and required you to check multiple mapmodes to see if you stepped over an edge etc. I do like bottleneck systems though, because feedback is usually immediate, but it suffered from not having much scaling cost as distances increased, so it was hard to use it to limit snowballing. As I mentioned it was also a system you didn't care too much about until you had problems, while historically, logistics was a vital part of planning a campaign. This led to combining the issue with another gripe of ours - that the way fronts moved in WW2 often followed important railroads, but don't really in HOI4. We came to the conclusion that we should try and make a system focused on railways and with a truck based component as a way to get more out of it when away from the rails.

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In our new system, supply flows from the capital (the total amount available depends on your total industrial base) through railways, where the level of the railway acts as a bottleneck. To transport more, you need a higher level railway (or a bigger port if it goes over water) so the railways are the current bottlenecks in a way. Depending on how much supply is transported you need a certain amount of trains for the rails to perform. Trains are a new equipment type that we will dig into in a future diary (well actually, several types ;P)

An important part of railways is that they are capturable, so as you push into enemy territory you will want to make sure to hold vital railways and capture railway hubs to supply your troops. There is a conversion time here to model the fact that there was usually some repair or re-gauging that needed to happen for attackers.

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Mapmodes are still quite WIP ;)

Rivers also had a huge importance on the eastern front for transport and supply so they will work essentially like basic railroads now, where you need to control both sides of their banks to use them to ship supplies around.

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Supply is drawn from what we call Supply Hubs now, which are either cities, naval bases, or manually constructed stations along the rails, which have to be linked into the network. Air supply works a bit differently but we will talk about this in the future along with some other supply additions...

The flow of supply from a Hub to a division depends on the terrain/weather etc, and ideally you want to have available trucks here (which is to say, motorized equipment) to increase the amount of supply you get as well as range. Cost of trucks and trains and losses to attrition and bad weather will be a limiting factor on your logistics.

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Overall, this creates a system where it's strategically sound to fight over railways, prepare for large offensives, to try and bleed each other's logistics capability and to force care when advancing in bad terrain and weather. The result is a much more fun, historical and immersive Eastern Front as well as adding a new layer of invasion planning in the rest of the world.

See you all next week for the next diary!
 
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So there's a new building called supply hub?
yes. its quite expensive because we generally want you to use cities and ports and fight for those. you also have new construction options for railways that you can draw etc
 
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Glad these are back. You mentioned you're still early in development. Is this looking like a 2021 release at this point?
assuming you meant to say this year, yes
 
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Yay! By the way are railroads constructable? Or are they preset?
we got historical ones but player can upgrade and build more. In europe its more about upgrading, in other areas more on building.

I hope that terrain will effect the cost of building railways
yes terrain impacts cost

^^

If I see correctly, if a VP does not have adjacency to a rail or a river (southeast france screenshot), it is connected by motorized?

I wish overland transport used not just motorized, but was split into trucks/horses, but I guess the abstraction of horses and motorized into motorized altogether makes some sense
it cant connect into the network as such, but trucks can be used away from rails. Atm trucks is something that may end up changing a bit but the idea is that without them you are basically running with horses so you dont get 0 if you dont have trucks. Oh and there is also some local supply still like before for small amount of troops
 
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Great diary, a few questions. :)

1) Can supply hubs be captured and their stuff used against you?
2) Do supply hubs use general "Supplys", or will you manually decide on what to put in? Like 1 Hub for fuel near the front, 1 hub for tanks further back? Is there a Logistics screen for every hub then?
3) How deep of a performance hit will this new system cause?

Great to hear from you again, the only sad part is, that it will all be released after the june anniversairy, so Q3/Q4.....
1) you can capture them, but its mostly to spread you access. which is like the core gameplay here - capture routes into the enemy land. We dont have any plans right now for say captured supply
2) there is no "supply goods" thats tockpiled its abstracted and produced by your collective industry
3) A good question, its more complex but the old one was also quite costly so we will have to see once its done

Does it occupy a building slots or is like AA and forts.

Also, how does it all fit in with infrastructure levels/construction?
Infra drops down to max 5 levels and some stuff comes from rails instead. they do a bit different things now. More details in future. it doesnt use the building slots so there is no competition

Will railroad routes from the start date be mostly modelled on historical maps or will there be some creative freedom for the sake of balance?
mostly but with artistic freedom, it also need to look good and make sense for gameplay
 
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Very happy about the inclusion of trains and railways to fight over, with improved logistics. Hopefully this makes the Soviet Front, but also the Chinese/Asiatic Front for Japan much more interesting after the system is properly balanced.
yeah it makes a lot more sense now to follow the historical path of the japanese invasion to hold the rails

Also, the most important question from me.

Will there be modelled trains slowly chugging along the map? With smoke. Possibly the odd whistle and chugchug sound if you zoom in close enough.

It is Needed.
yes. they are... disturbingly bright pink atm so we will talk about those later when we have proper art for them

I'm guessing these are primarily intended to use in areas lacking in urbanization, such as... Siberia... or Central Africa..?
yes exactly

Trains are a new equipment type that we will dig into in a future diary (well actually, several types ;P) So big armored trains and artillery trains incoming or not ??
;)

Will railroads connected to recource locations increase the amount of recources you get?
sortof yes. more details in future tho
 
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Did I get it right that just cutting off the capital with a naval invasion or paratroopers is no longer a viable tactic to starve all enemy units quickly?
the system still depends on shipping from capital but there are some ways to deal with this I will talk about later

A good abstraction would be that you had some supply flow even if you didn't have enough trucks, to simulate supplies transported by horse.
yeah thats the idea. they arent needed, but unlock more potential
 
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Will the trains run on a new resource: coal? Also, will units move slower in normal territory now that there are train tracks or will the speed be the same as before?
you mean for strategic redeployment? I am hoping we can tie it together so most of the speed buff comes from rails but we havent done that yet
 
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Also, I can't wait to see if the very much unintended legacy of George Washington Whistler, namely a wider railway gauge than its neighbors translates into anything meaningful for the Soviet Union in game terms.
this question took longer than I expected ;D we arent sure yet. we discussed having a modifier on soviets to represent it takign longer to convert to-from its gauge, but its also sorta abstracted in the conversion/repair everyone needs to do
 
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I'd be interested about knowing if this new system could have some impact on land combat apart from logistics, namely Armored Trains or Railway Artillery which were used before and during WW2.
There will be more details on other railway related stuff further along
 
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Does this mean we can parachute and capture strategic railroad network to starve the enemies frontlines?
yes so those will be important to guard if you dont have alternate routes
 
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Will railroad routes from the start date be mostly modelled on historical maps or will there be some creative freedom for the sake of balance?

They were modelled on historical maps (although finding good maps for 1936 specifically was a bit of a challenge, so I had to use maps from the late 20ies and early 30ies). That said, there were a number of creative decisions for the sake of balance and performance. Not every possible railroad was included, and I aimed more for representing the major network layout (so the French network is heavily centered around Paris, for example) instead of representing every railroad ever. For large parts of central Europe, being completely accurate would have meant covering every province with railroads in ever direction, making them somewhat pointless (and more performance intensive as every unit has to constantly calculate which of the hundreds of nodes is the correct one to draw supplies from). We are still tweaking the system though, so we may decide to add a few railways that don't exist in 1936 but would be complete no-brainers to build at the game start to fix glaring supply issues in various places (The Japanese-Chinese frontier is a bit of a problem child in this regard).

In the final resort, if we have to choose between building the entire system around working with a 100% accurate historical setup or adding a single low-level railway somewhere and have it work with an otherwise balanced system, we will do the latter.

now that railroads are implemented, what role will the infrastructure have apart from more resources and faster factory construction speed? will the focuses that gives you infrastructure also give you railroads in said states?

It depends. The Autobahn focus does not give you railways, but the Australian and Indian focuses talking about railways do. They either upgrade existing railways or add some in places that I thought it would make sense.
 
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Very interesting DD.

Question, assuming you can attack enemy rail lines with aircraft, will there be changes to the air system so players are not playing whack a mole chasing enemy bombers as is required now with strategic bombing?
Not for this DLC, but its a thing I want to do when we get back to looking at air warfare. its too microey on the defense now imo

As a South American I`m pretty much resigned to the fact that we are not going to get a SA DLC anytime soon. But yes Iran would make sense to be included and the next smaller DLC would be Scandinavian focused.
My product manager is brazilian so there is not a day when he doesnt nag me for a south american pack actually ;D

Hey Hoi4 developers, when do you think we might get some focus tree dev diaries? Will you guys cover supplies first then move on to focus trees?
oh pretty soon. i like to mix some mechanics diaries in between focus tree diaries, also this time we are probably gonna split some of the focus tree diaries into two because they are quite large this time around.

Also guys, there is no Italy in this expansion. It really doesnt fit in with the rest and I am a bit surprised that people expected that it would be because we try and keep to themes or close areas (mexico is in MTG because its a neighbor of USA and someone really wanted to make mexico). I had some plans to include it in MTG because of italys naval connections but that DLC got too big with all the other majors in there so there was no room. Italy needs and deserves an expansion with a theme and other nations that supports it imo
 
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My product manager is brazilian so there is not a day when he doesnt nag me for a south american pack actually ;D
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I will not rest until this is in the game. One day... one day...
 
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Excellent DD I aprecciate your work !

Btw Since it's going to be a land warfare update. Should be expecting something in form of MTG tank designer or it will be decided yet?
I feel like I spoiled enough stuff for today feature wise ;D look forward to future diaries for more stuff
 
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