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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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For some background and info - it's definitely the case that much of the fuel used in the UK was refined overseas (although prior to Jun '41 US imports were relatively minor, maxing out at 18.6 per cent of the total between Dec '40 and May '41). From Jun '41, US fuel/oil supplies steadily rose until they comprised around 75 per cent in 1943.

Britain did have significant domestic refining capacity (although only enough to meet around (very roughly) 15 per cent of local demand in the first year of the war), but the amount of fuel refined locally actually fell during the war because refining locally meant a greater volume of oil needed to be imported (I can look it up, but iirc they saved about 15% of volume on tankers by importing refined products rather than crude oil). Thus, refineries were left idle to save tanker space.

After Britain, the largest source of oil was from the Caribbean, where Island refineries took fuel from Venezuela and other nearby fields. Prior to US supply taking over the lions' share of imports, it was Caribbean fuel that formed the majority of imports to Britain. Imports from the Middle East (Iran and Eastern Med, which was largely Iraq but also included some oil from Romania, which Britain bought to try and keep it out of the hands of the Axis) but the Caribbean was the most important source, and had enough refining capacity alone to meet most of Britain's needs in the first years of the war.

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View attachment 440080

OK - you can all go back to being more exciting now :).
im a bit anoying becose the fuel and UK is same special and unique and for GERMANY, as well for france if they font die fast.
This thing of refineries and where is fuel produced is a bit more complex for normal handle on direct pools.
In ww2 oil was so complex that should be some how compensate. But... mybe this colonies could be made as puppets and send fuel as land lease or something... i dont know. Pointing UK im not sure a solution... easy solution.
 
4-6000 horses in an infantry division need to be spread over many square kms if they're going to be living off grass long term, and as I said that dispersion makes it difficult to use them for their daily supply hauling duties. In any case, over winter in many parts of Europe there is no grass to eat, so they need fodder.

If they are going to "live of grass long term" (staying in place ) then they won't be needing to haul any of the heavy stuff like the hundreds of guns ( Artillery, AT, AA ) in a division.

The east front for example during most of the war was at least 2000km long, and was covered by 150-200 German divisions, so the average length a division would be expected to cover would at least 10km. By just going 2 km in depth behind your own lines that's 20 square km or 4000 square meters per horse ( 63 x 63 meters or not far from a football field each ). Artillery or supply dumps would often be located even further back than that from the front though, and speaking generally the longer a division needs to stay in the same place the less action they see ( less ammo need, more secure/better quality roads, railheads built up closer ), so the less issues delivering supplies will be = less work for horses.

Way to cherry pick data - just ignore that I said Allied divisions were 2-3 times larger than German ones in 44/45
I tend to ignore data which is factually wrong. My apology for not making that clear.

A German infantry division would be over 17000 men in 1941 and about 13000 men in 1944, while a US infantry division in 1944 would be about 15000 men. Even if we use the most extreme numbers in favor of your example and assume an under-strength German division ( which most certainly is not what they used to calculate daily supply needs on ) we are stretched to make a case of a US division being more than at most 1.5 times larger than a German.

Heck even a German 1945 Volkstrum division would be over 10000 men strong!

...and even though number of artillery tubes were comparable, the number of shells fired per gun was much higher for the Allies.
This is a valid point, higher ammunition expenditure of allied divisions is a plausible explanation for some of their increased supply needs, and not just for artillery but for all types of weapons. I still think motorization and vehicles is another main reason though.

Divisions have a fixed need for some supplies, mainly food
Again, food is not a major part of a divisions supply needs. 15000 men x 3 kg ( using your own higher number here ) is 45 tons, not even 10% of the 700 ton per day daily need listed.

Even if you include fodder for 5000 horses in "food" ( 10 kg x 5000 = 50 ton ), it's still not the major portion of needs.

Ideally from my point of view there should be 3 categories of supply - general, fuel & ammo. General supply, needed to keep troops & horses alive etc, should have first demand against supply capacity, then fuel, ammo & replacements should have to use what's left. This would mean that having too many units at the end of a long supply chain would result in them withering away through losses that could not be replaced. Building up for offensives should take a long time if 90% of the supply capacity is used for food, as only 10% is available for ammo & fuel.

I don't think going down to that level of micromanagement would be beneficial to the game. Adding ammo, sure thing, but all 3 of them ( basic supply, ammo and fuel ) can use the same system of delivery. It's rare to read about a situation of grave shortage in WW2 where just one of these were missing, generally if divisions get cut of or in situations of bad supply deliveries of all 3 will start to lag behind. The effects of each could instead be tweaked so that the penalties associated with them become severe after different times much easier than it would be to create 3 parallel supply flows.

I agree with the stated goal you have ( bad supply = longer time to build up for offensives ), but don't fully agree with the way to get there. Building up for offensives is in HoI4 represented by planning bonus, so that needs to be worked into it somehow as well.
 
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@Archangel85

Two questions:
  1. Will you be adding an extra command power button for the purpose of further prioritizing fuel?
  2. During combat, will land units defending use less fuel than land units attacking?
 
My guess is that it'll be added when they add Supplies as a resource, which will probably come with better Resistance mechanics, e.g. Guerilla Warfare Doctrine.
Do you know if they have concrete plans doing that in a coming update? Or just a guess (not that it is unlikely that they add supplies and better Resistance)?
 
Some nations, such as the US, could probably do whatever they wanted since they would have so much oil, and industrial capacity to build refineries. Germany on the other hand would likely struggle with it as they did in real life. But you're right, it will all depend on how it's balanced.

im a bit anoying becose the fuel and UK is same special and unique and for GERMANY, as well for france if they font die fast.
This thing of refineries and where is fuel produced is a bit more complex for normal handle on direct pools.
In ww2 oil was so complex that should be some how compensate. But... mybe this colonies could be made as puppets and send fuel as land lease or something... i dont know. Pointing UK im not sure a solution... easy solution.

The Allies should be able to rely on the massive oil reserves of the US and Caribbean nations to power their military, IF they can get the oil to where it needs to go. The Axis can try to stop that via convoy warfare and/or a strategic air campaign.

The Axis needs to build up a reserve of oil large enough to power their military until they can both build enough synthetic factories and capture enough oil to keep their tanks, ships, and planes moving. The Allies can stop that by defending the resources, sinking Axis tankers, and/or strategic bombing.

That is the obvious goal of this patch from reading diaries. Hopefully it will be balanced enough to work for all nations, and the strategic air campaign can be improved enough to satisfy MP complaints.
 
It is quite ironic that they are now adding a lot of the features that got axed from HoI3. Remember how Johan et al justified that, by arguing that the features weren't fun, or too much micro-management, or too difficult for new players to comprehend and so on? It certainly wasn't to sell more DLC - release a barely functioning, bare-bones base game and then milk the fanbase with expensive DLC for years to come. It was worked so many times, why change the recipe.

And you guys argue for ten pages about the details, when all of you are going to buy it anyway.
 
It is quite ironic that they are now adding a lot of the features that got axed from HoI3. Remember how Johan et al justified that, by arguing that the features weren't fun, or too much micro-management, or too difficult for new players to comprehend and so on? It certainly wasn't to sell more DLC - release a barely functioning, bare-bones base game and then milk the fanbase with expensive DLC for years to come. It was worked so many times, why change the recipe.

And you guys argue for ten pages about the details, when all of you are going to buy it anyway.

Yeah, they bring more feature but refused to do things like Expert AI mod!
the more feature the worst AI because it cannot handle all of it.
 
It is quite ironic that they are now adding a lot of the features that got axed from HoI3. Remember how Johan et al justified that, by arguing that the features weren't fun, or too much micro-management, or too difficult for new players to comprehend and so on? It certainly wasn't to sell more DLC - release a barely functioning, bare-bones base game and then milk the fanbase with expensive DLC for years to come. It was worked so many times, why change the recipe.

They did this with HoI3 too. 3 was totally barebones at release, then slowly they added back features and content that was there in 2, through a paywall of course. The last expansion in 2012 more or less brought HoI3 up to the same quality as HoI2 had been for years, though mostly with much less historical flavour (e.g. HoI2 had at least 4000 events IIRC, HoI3 had maybe 200-300).

We'll see how far HoI4 will go, and if it'll truly become a better WW2 GSG than HoI3 or even AoD.
 
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I was thinking more like (all based on the M3 Halftrack):
T19 105mm Howitzer Motor Carriage (M2A1 105mm Howitzer)
T30 75mm Howitzer Motor Carriage (M1A1 75mm Howitzer)
M13 Multiple Gun Motor Carriage (Twin .50 cal M2HB Machine Guns)
M15 Combination Gun Motor Carriage (M1A1 37mm AA Gun with twin .50 cal M2HB Machine Guns)
M16 Multiple Gun Motor Carriage (4 .50 cal M2HB Machine Guns)

For the Sd.Kfz 251 we have:
Sd.Kfz 251/9 Schützenpanzerwagen (7.5 cm KwK37 - Same mount as the StuG III)
Sd.Kfz 251/10 Schützenpanzerwagen (3.7 cm PaK - AT version)
Sd.Kfz 251/17 Schützenpanzerwagen (2 cm - AA version)
Sd.Kfz 251/21 Schützenpanzerwagen (3 Drilling MG151s - AA version)
Sd.Kfz. 251/22 7.5 cm PaK40 L/46 auf mittlerem Schützenpanzerwagen (AT version)
Not to mention the Wurfrahmen 40 which was mounted on either the 251 or captured foreign hardware like the Renault UE Chenillette or even the M3 Halftrack.

T19 Howitzer Motor Carriage (105mm M2A1 Howitzer), yes this one can be called as "SP artillery", and Sd.Kfz. 251/22 (75mm PaK40 AT) as a AT unit, but I cant find other examples.

For the difference between independent Art/AT/AA unit and support Art/AT/AA in infantry units, field gun>=75mm, howitzer>=105mm, AT>=75mm, AA>=75mm are general organized as independent units historically. Unlike katyusha rockets, Wurfrahmen 40 is not usually formed as battalion level unit and used en masse.
 
This is a valid point, higher ammunition expenditure of allied divisions is a plausible explanation for some of their increased supply needs, and not just for artillery but for all types of weapons. I still think motorization and vehicles is another main reason though.

Again, food is not a major part of a divisions supply needs. 15000 men x 3 kg ( using your own higher number here ) is 45 tons, not even 10% of the 700 ton per day daily need listed.

Even if you include fodder for 5000 horses in "food" ( 10 kg x 5000 = 50 ton ), it's still not the major portion of needs.

I don't think going down to that level of micromanagement would be beneficial to the game. Adding ammo, sure thing, but all 3 of them ( basic supply, ammo and fuel ) can use the same system of delivery. It's rare to read about a situation of grave shortage in WW2 where just one of these were missing, generally if divisions get cut of or in situations of bad supply deliveries of all 3 will start to lag behind. The effects of each could instead be tweaked so that the penalties associated with them become severe after different times much easier than it would be to create 3 parallel supply flows.

50 or 100 tons of general supply per day may not be that important for a motorized/mechanized division in Europe, but it could be a problem in Asia/Africa/Middle East/Pacific Islands and make up a large portion of the total suppy need of Infantry/Mountain/Marine/Paratroop divisions with few or no trucks.
 
SPG/SPAA/TD on Light tank chassis please
Maybe I don't get what you want to say but we already have this...

/edit: IRL all possible configurations were built. There was rocket artillery on tanks (Calliope), rocket artillery on half tracks (mec) like the aforementioned Wurfrahmen 40 (on SdKfz 251) also dubbed as “Stuka zu Fuß“ (Stuka on foot). And ofc tube artillery/aa/at on all possible platforms.
 
Can you take fuel from subjects, if they have a surplus and you require it?

That's a good question. Oil is still a tradable resource, so it will be possible to obtain crude from subjects. Perhaps Fuel should be made available through Lend-Lease?

You say we can prioritize fuel allocation between military branches. Can we further sub-divide that by theater, fleet, or wing/air zone? For example, maybe I am the UK, and the Channel Fleet is the most vital thing in the game for me. But the second most important thing is my fighters and heavy fighters securing the skies over southern England, even more so than my smaller fleet hunting for German convoys off the coast of Norway. Can I say "channel fleet is priority 1, southern England fighters are priority 2, other fleets come after that"?

I would expect fuel to be distributed according to the existing prioritization settings (per Theatre for land, per wing for air, etc.). However, AFAIK that is only going to be relevant if the player has a fuel shortage, which is hopefully not going to be a common experience.

Instead, players will allocate fuel using the Mission system and aggression settings. If the UK's priority is Fighter Command and the Channel Fleet, then you will order the light Fighter and Heavy Fighter wings in southern England to carry out (fuel-intensive) Air Superiority missions and the Channel Fleet to be an an aggressive Strike Force, and you will create other large fleets to intensively Patrol the Narrow Seas. Your other fighter wings will be on (fuel-minimizing) Intercept, while your other fleets and bombers will sit quietly at home (or send most of their strength back to the reserves).

That seems much more sensible that wasting dev time (especially AI dev time) developing a mechanism that only permits a certain percentage of ships to sail/aircraft to fly according to their fuel ration.

I think you are reading to much into that graphic. I thought it meant "Fuel Prioritization to Army" (which at the time of that graphic uses the Mil Factory Icon), "Fuel Prioritization to Navy" (which uses the Dockyard Icon), etc.

I don't think the lower part of that screenshot actually relates to fuel usage. I interpreted it as two halves:
- top, the new fuel prioritization settings
- bottom, the summary of factory and dockyard utilization and resources (which is already in the game).

After Britain, the largest source of oil was from the Caribbean, where Island refineries took fuel from Venezuela and other nearby fields. Prior to US supply taking over the lions' share of imports, it was Caribbean fuel that formed the majority of imports to Britain. Imports from the Middle East (Iran and Eastern Med, which was largely Iraq but also included some oil from Romania, which Britain bought to try and keep it out of the hands of the Axis) but the Caribbean was the most important source, and had enough refining capacity alone to meet most of Britain's needs in the first years of the war.

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View attachment 440080

For the sake of completeness, it should perhaps be stated that the two Fuel tables are showing different things. The top table shows imports to the UK (i.e. Great Britain and Northern Ireland), which mainly came across the Atlantic from the Caribbean and later the US. The bottom table shows the global picture, which is quite different, because Commonwealth forces and territories East of Suez were supplied from Abadan in Iran (and until 1941, Borneo and Burma).

In game terms, this means that when British Oil concessions are added to Persia/Iran in a subsequent DLC, then they should perhaps be somehow assigned to AST, MAL, NZL, and RAJ as well as ENG.

IRL, it also helps to explain why the UK government was so upset when the Iranian government nationalized the gigantic Abadan oil refinery in 1951.
 
yes, its effectively the grace period.


Here is a tooltip for perusal:
View attachment 439643
Could the tooltip have two end dates instead of one?
"With current usage the fuel will run out in X days"
"With maximum usage the fuel will run out in Y days"
 
Yeah, they bring more feature but refused to do things like Expert AI mod!
the more feature the worst AI because it cannot handle all of it.
here i will defend developers, some day yhey will pimp ai near to the level of expert ai. Expert ai doesnt build anew feature just make more reactives ai behaibour.
i bealive they will get a effor in ai when they solve the problems with frontline logic, airwings bug and the supply and commerce revamp. when they complete the to do list.
 
Some nations, such as the US, could probably do whatever they wanted since they would have so much oil, and industrial capacity to build refineries. Germany on the other hand would likely struggle with it as they did in real life. But you're right, it will all depend on how it's balanced.

"General, do you know what this means? It means that the Americans have planes and fuel to fly chocolate cake across the Atlantic Ocean! They have no concept of defeat!"
 
Aren't supply and fuel now separate with supply thus representing all non-fuel supplies. Presumably the ability to move fuel through the supply chain will be limited by infrastructure & supply bottlenecks just like replacement men & equipment, so it has its own burden rather than needing to be included as part of the supply footprint. About 1/3 of US supply was POL. Now if there's no additional supply chain burden from getting fuel to units, then yes motorised units need to have fuel use included in their supply footprint, but I'm hoping the devs have not made that mistake, and I wanted to illustrate that horse drawn logistics have consequences that aren't well modelled at the moment.
I believe you are over thinking this last bit. Supply usage in HOI4 is just a number assigned to the unit. There are no supplies per se being consumed. Therefor the separation of fuel changes absolutely nothing in the supply model since the abstract concept of fuel was already taken into account when setting the size of the supply footprint of various units initially.

I suspect that when you actually run short of fuel this will not be represented as the unit drawing less supply in the region. Although this abstraction is flawed in that sense, it is nothing compared to some of the flaws with resources and industry.
 
There are three technical paths that should be linked when discussing armour, artillery, AA and AT. transport, tube size and ammunition types. AT and armor share ammunition: armor piercing, HEAT and Sabot. Each one more deadly than its predecessor. The size of the tube determines velocity, distance and piercing. Transport such as tracks, half tracks or wheeled. Each should be researched and as its researched different models are available to be built. I know you have abstracted some of this. It does seem to me that the AT track has differing ammunition, but the armor track does not. There is a big difference between a HEAT round fired from a 50mm tube and a armor piercing round fired from a 75mm tube.