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HoI4 Dev Diary - Fuel Review and Motorized Artillery

Hello and welcome back for the first dev diary of 2019! Today we will update you on the state of fuel as well as show you a little something many people have wanted for a long time.

Changes and Updates to the Fuel Implementation

When the game launched, oil was used as other resources for the purpose of production. This was an abstraction done for fuel consuming equipment. We have removed this abstraction but are still using a simplified version of what happens in the real world. Oil refining was and is not as simple as simply processing it into a multipurpose “fuel,” but we felt that this simplification was necessary for gameplay and consistency of depth of detail.

We have added fuel as a resource to the top bar. With this UI element we convey a few bits of information. The numbers show the amount of time you have before being full or dry. Here the number is green and indicates that the stockpile will be full in 361 days. The numbers will become red if fuel is being lost. The green bar indicates the state of the stockpile, showing how full it is. The arrows indicate that fuel is currently being gained.

top bar fuel.png


Oil is still traded as it was previously but is no longer used in any production. Instead, excess oil is converted to fuel at an hourly rate. The trade UI has had some slight updates to take this into account. What was formerly the “production” category is now “need.” Oil now has special subcategories of this section. Active need and potential need are now represented with “A” and “P,” explained more thoroughly in tooltips. This helps give the player an understanding of how much oil needs to be traded if they wish to try and cover their current fuel needs with a constant supply from oil refining.

fuel trade ui DD.png


Refineries have also been changed from giving Oil resources to giving hourly fuel. This both makes more sense from a historical perspective and makes it easier to control how much resource is produced by refineries. Previously, tech increases could only allow for a minimum increase of a single unit of oil. This gives developers and modders much better granular control over the output of a synthetic refinery.

For countries that will not have enough fuel production during wartime to meet their needs, developing a healthy stockpile is an option. Most nations will not start with a large stockpile capacity. Stockpile potential will be reduced by economy laws for many nations. Also, increasing stockpile capacity requires some investment, and will take space away from industry through the production of silo facilities. Japan is a good example of a nation that may run into a situation during the war when their usage far outstrips their potential fuel gain, so they will need to have a decent reserve of fuel if they want to fight the US in the Pacific.

fuel_1.jpg


To help understand what is going on with your fuel stockpile and to manage distribution when fuel has become tight, we have added fuel as a special section to the logistics tab. This includes a breakdown of usage by military branch of the military and the ability to control who gets priority for fuel distribution. A special variant of the stockpile menu used for other equipment shows a breakdown of fuel consumption by day, month, and year as well as a breakdown of the state of the stockpile over time.

fuel stockpile menu.png


The logistics support company has also been changed and will help with keeping your armor fuel usage more manageable.

image (1).png



Motorized Artillery Units

When Hearts of iron 4 was released, it featured a very large number of possible battalion types that you could use to design your divisions. However, there were a few unit types that were pointedly absent. For example, if you wanted to make a motorized infantry division that was a faster version of your regular infantry division with line artillery - you couldn’t, unless you were okay with slower speed.

Part of the reason for this was the feeling that a motorized artillery unit didn’t have enough of a drawback to be a meaningful choice - it would just be better than regular artillery, and the added cost of a handful of trucks was not a major issue if you were building trucks anyway.

mot_arty_1.jpg


With the addition of fuel, that has changed. Now it is a long-term decision to motorize more of your force, and it requires more planning as your army suffers increasing penalties if you can’t meet fuel demands. So we decided to add motorized artillery units in regular artillery, rocket artillery, anti-air and anti-tank flavors. They are, by and large, identical in firepower to their horse-drawn versions but require 50 trucks each, have a roughly 50% bigger supply footprint and, of course, require fuel to run properly.

mot_arty_2.jpg


No special tech is required to unlock motorized artillery; having motorized equipment and the respective artillery type researched also unlocks the motorized unit.

That’s all for today, tune in next week when we talk about changes to research and show off the new naval tech tree!
 
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You can't just park the fuel storage anywhere - it needs to be near where the rail networks are, the highways, and in a large enough open space - barring underground storage. It also needs to be far enough away from population centers so a POL fire doesn't become the sort of catastrophe that can't be discussed on these forums. There is only so much industrial land in a given province. You can't just park fuel silos hither and yon.
 
Any reason why fuel silos take up factory spaces? Why shouldn't they work similar to bases/defenses. Maybe each additional level of silo is locked behind a fuel capacity research.
desing choise, but i bealibe that if you uses the slots as infra it will be much complex to calculate the losses and transfers of oil.
 
Let the debate on strat bombers being allowed in MP begin. If Germany is allowed to build unlimited synths and fuel capacity without fear of bombers, and doesn't have to worry about researching AA techs, building Positional AA, and building heavy fighters she is going to be a monster. Motorized Art is going to change template a lot. Also affects the meta on going Concentrated vs Dispersed.
Looking in from the outside (as I only play SP) that always struck me as one of the sillier house rules.

I am also waiting for the spreadsheet debates on Motorized ART/AT -vs- Light TD/SPART, especially as IC cost for Motorized AT and Light TD will be remarkably similar.
 
Any reason why fuel silos take up factory spaces? Why shouldn't they work similar to bases/defenses. Maybe each additional level of silo is locked behind a fuel capacity research.

You mean like forts?

I like this idea a lot more.
I would think more of a statewide building like Air base, Radar and AA, but I also like this approach.
 
You can't just park the fuel storage anywhere - it needs to be near where the rail networks are, the highways, and in a large enough open space - barring underground storage. It also needs to be far enough away from population centers so a POL fire doesn't become the sort of catastrophe that can't be discussed on these forums. There is only so much industrial land in a given province. You can't just park fuel silos hither and yon.

But couldn't you place fuel silos further out from population centers than factories since silos require fewer people to operate? As long as you build the necessary infrastructure to connect it to the highway/rail system.
 
Will the support companies that require trucks require fuel now? That seems like a headache for low industrial nations. Idk if its realistic or balanced, but I like the idea of horse driven alternatives.
 
Any reason why fuel silos take up factory spaces? Why shouldn't they work similar to bases/defenses. Maybe each additional level of silo is locked behind a fuel capacity research.

For balance reason, if you could simply build silos just like forts Germany, Japan and Italy could just get the tech, build the stuff and then forget about fuel problems for the rest of the game just because they can have a stockpile that can last until the end of the war.

With that fuel would become a no-factor like in HOI3
 
We have removed this abstraction but are still using a simplified version of what happens in the real world. Oil refining was and is not as simple as simply processing it into a multipurpose “fuel,” but we felt that this simplification was necessary for gameplay and consistency of depth of detail.

I wonder how fuel consumption is affected by "active" units. In other words, units engaged in movement or fighting. Do they use more fuel, or would that complicate the system too much? I'd be a little paranoid about my usage rates if I had to worry about that. There's a trade-off between realism and fun somewhere in there.

ah the argument, more fun or more realistic. I gave up on getting a real wwii simulator. too difficult to develop to run on a simple workstation. Maybe the pentagon uses a super computer.

It would be cool if you added mechanized Artillery Although this wouldn'd be so historicly accurate

Technically, in a historical sense, yes. But what is represented in game is tank based not mech based. Both Germany and the US (not sure about others) had a wide range of Half-Track based SP-Artillery and AA (not so much on AT).

half-track mounted artillery, AT, or AA guns, would best be represented by an alternate set of equipment to fill out light SP artillery, SP AA, and light tank destroyer units. imo.

Would it be possible to ask that Artillery not add to the width of a division? Artillery is 12 to 18 km behind me. I only see the shells landing in front of me, every once and awhile I see the trucks, half-tracks or self propelled beasts as I move into position.

and while we are it, where are the Russian Artillery corps in the game a good 24km behind the lines with their 152mm tubes lined up hub to hub?


Just a little something to think about on my 500th post
 
It's cool to see artillery that can be transported via trucks, but what about tanks? Historically, countries such as Germany used large trucks to transport light and medium tanks over long distances to prevent resource consumption and wear on the tanks themselves. Will this ever be implemented in the form of a special line unit type or perhaps a support unit?

Pros:
(Would save fuel, increase division speed, and increase reliability)

Cons:
(Initial production more expensive, unit loses more organization while moving, limited to select countries such as with the bicycle divisions)

Proof of concept:
 

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It's cool to see artillery that can be transported via trucks, but what about tanks? Historically, countries such as Germany used large trucks to transport light and medium tanks over long distances to prevent resource consumption and wear on the tanks themselves. Will this ever be implemented in the form of a special line unit type or perhaps a support unit?

Pros:
(Would save fuel, increase division speed, and increase reliability)

Cons:
(Initial production more expensive, unit loses more organization while moving, limited to select countries such as with the bicycle divisions)

Proof of concept:
Strat redeploy models that pretty effectively.
 
the ty
ah the argument, more fun or more realistic. I gave up on getting a real wwii simulator. too difficult to develop to run on a simple workstation. Maybe the pentagon uses a super computer.

types of fuel is mybe too deep to hoi iv concepts, but at least fuel usage and production well modelled could be a radical change for game. I preffer refineries as building inspite of having fuel/gasoil/planes fuel.
 
Do we have the option to motorize our logistics for better supply at the cost of heavy fuel use?
 
Is strat redeployment still an effective system with a fuel system in-place?

@podcat this is a really good point, is there a fuel discount for strategic redeployment since you're really using trains and the like rather than actually driving them around? If so, how much is the discount? Does it only apply to states with above a certain level of infrastructure, everywhere, other conditions...?

Edit: should have paid better attention to who posted the diary. Podcat can answer if he likes, of course but I believe I meant @Archangel85
 
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Would it be possible to ask that Artillery not add to the width of a division? Artillery is 12 to 18 km behind me. I only see the shells landing in front of me, every once and awhile I see the trucks, half-tracks or self propelled beasts as I move into position.

Besides combat width not actually representing the number of men you can fit shoulder to shoulder on the front line in this game, this is also actually an inaccurate representation of the artillery warfare of the time, given that many of the guns were used even in direct fire roles quite often and to good effect. Very long range bombardment was a thing, but generally only when bombardment was verging on the sub-strategic rather than tactical level.
 
Yay!
 
I am somewhat concerned about the AI being able to handle fuel. Even conceptionally it seems a hard AI problem. How would i.e. the Japan AI know, when it is crunchtime and fuel ressources should be spent as if there is tomorrow e.g. for its carriers and when to sit on its hands and save fuel for the right time. If the AI runs dry on fuel, it looks to be easily exploitable. Maybe the AI should cheet?
 
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