Hi everyone, welcome to another dev diary! Last week we talked about changes to frontlines (both UI & backend and AI) and today I want to talk about some of the other fixes and changes we have been up to.

1.7 ‘Hydra’ is a chance for us to rewrite and improve some pesky systems and to step up and go 64-bit, so this diary is going to get a little technical

64-bit
1.6.2 will be the last 32-bit build of HOI4 and we will be leaving it (and older as normal) on steam for those who still want to access it (and make sure to mark the build). We also will not be converting any of the old versions to 64-bit. It would simply be too much work. Because of this we have decided to up the big decimal on our version number to 1.7. 1.7 ‘Hydra’ will be fully 64-bit supported on Linux, Mac and Windows and it has been a big undertaking. There are many reasons for this change. Some platforms like Mac are phasing out 32-bit quite aggressively and we don’t want to end up with people not being able to play on there. 64-bit lets us use newer compiler features and a lot more possibilities code wise in the future. It is also about time, because it felt like a lot of the industry did this over 5 years ago

As a player you won’t notice a huge difference. We haven’t seen any big performance improvements for example, although I wouldn’t say that it’s impossible some areas might improve as our investigations have been pretty shallow. 64-bit is tricky in that on one hand we get access to the possibility of more optimized code, CPU registers etc, but it also takes up more memory, and memory is often highly impactful on speed too. We see it as an investment into the future where we know we can start taking advantage of things now that the foundation is in and make it easier for us to work.

We have already seen some of this internally where we during this work have been able to replace a lot of basic code structures dating back to the Year of our Lord 2003

Convoy system
The old code system keeping track of your favourite little boats has long plagued development, and after 1.6, when we still had some issues, we decided it was simply best to take it out back and shoot it. 1.7 comes with a new system rewritten from scratch. The old convoy system was operating in a way where everyone could control it, and by association, everyone could also break it at any time. It would also swap convoys in between the country’s supply and the assignments at every single tick, swapping them around all the time, and convoys getting lost because there was no sense of ownership and control over the convoys. It was a nightmare.

The new system is a centralized system where each country has one instance of a class that has full ownership and control of convoys, and any other gameplay code that needs convoys can request them from this system but never have real control over them. This “magically” fixes bugs with convoys disappearing from the game because it’s not possible to write code like that anymore. It’s stability by design along with the other great and exciting stability changes that we are bringing to you with this patch.


Naval Balance Changes
We have been looking at convoy escorting, subs, detection and raiding and making improvements:

• Subs can now fire also while withdrawing
  • Convoy escort missions were too binary. Either you have protected the convoys in time or not. Arriving on time provided too much of an advantage to the escort and thus made sub raiding less viable. Subs will now get an extra volley or two in most combats, making raiding with high-quality subs against low-quality escorts more viable.
• We increased submarine detection chance from passive detection (hi bitmode) and lowered detection chance from firing torpedos. Detection chance from passive sweeps now scales parabolically so that large differences in detection and visibility will be much more pronounced.
• We gave carriers passive sub detection and gave them a detection increase in doctrines. This makes them more viable in their historical roles in the Atlantic.
• We also increased detection values on some later radars and a bit on sonar, to make detecting subs a bit easier.

We have also been looking at various issues related to convoys and how they defend themselves against naval bombers. There were many different problems:

• Unit transports died too easily vs naval bombers, this was extra bad for the AI which generally suffered more to this than a player would.
• In small naval bombers vs transports as above, we also had way too high casualties for the planes
• Because convoys are not “real” units they would heal up after battle, so unless you sunk them there was no real damage to the enemy.

To deal with this, we have made several changes:

• Troop transports get a special defensive boost in the particular case of being attacked directly by naval bombers
• The anti-air formula for ships shooting back has changed so that partial damage is taken into account. We now essentially roll a dice for partial damage allowing it to kill planes. Before, weak ships like convoys that got hit a lot had much to big an impact, and early naval bombers didn't really deliver. This should be a lot nicer now.
• At the end of battles we add up all the damaged convoys and for a fraction of them we roll a dice based on the damage to see if they sunk from that damage. The kills get attributed to the last to strike them during the regular battle.

When it comes to regular combat we wanted to help out carriers and capital ships a bit and we felt the more realistic way of doing that was to give them a time at the start of the combat when they are the only ones active. Carriers and aircraft are active straight away. Some ticks later capital ships and subs get to fire and last screens. This gives a bit of a boost to those bigger ships and represents their longer ranged weapons better.

Script-Side Performance Improvements
1.6 came with a number of new script features to improve performance for targeted decisions. Previously these decisions would check every country in the world every day, and with some of the more complex triggers that could amount to quite a bit of number crunching. With the new features, we can pre-restrict the list of targets to reduce the necessary number of checks. Unfortunately, the new script features came too late in development for us to utilize these features in the initial release and other bugs took priority.

Thankfully, a member of the community by the name of Antoni Baum (aka “Yard1”) did make the effort to go through our script and fix all the places where the new features would make a difference (as well as a few triggers where a small reordering of script checks resulted in better performance). This work has been merged into 1.7 with permission. While it is difficult to measure the immediate performance effect of these changes, we saw a performance improvement of about 5-10% depending on the overall gamestate, number of wars etc.

We planned to put 1.7 out as an opt-in beta tonight but we hit some snags (which is why this diary is a bit late ) but we think we should have the open beta tomorrow with patchlog for those brave enough to help us test it

See you again next week!

 

[DuoDex]

Glad to see that carriers are getting a buff, but I still can't shake the feeling that they've been shoehorned into a system that is intended to model gunnery duels, not carrier battles...

I have been thinking of doing something where CAS is better vs armored targets compared to NAV to give them both a role, but that would require quite a lot of changes to both plane combat and naval combat.

That's an interesting idea, although I'd suggest that instead of making dive bombers more effective against armored vessels you make them more have a very high critical chance and critical multiplier while not actually hitting very often (and it's easier for them to hit larger vessels than smaller ones), whereas torpedo bombers might be more reliable but not necessarily causing massive damage...I'd rather take a Mk 13 than a 1000lb bomb to the face, especially if I've got TDS...

It's hard to model this in HOI4 though as really naval aviation was a bit of a crapshoot anyways.

 

[Axe99]

Pre-radar, that is not at all certain, especially against dive-bombers. The Japanese carriers at Midway launching extra fighters to combat the dive bombers failed to get in position in time to disrupt the attacks, while late 1930s Royal Navy thinking assumed that fighters could not intercept attacking bombers in time, and hence lead to powerful AA and armoured decks for those carriers designed for the European theatre. The 1941 attack that crippled Illustrious illustrated the point despite her having radar, the Ju87s were detected only 28 miles away and like Midway the CAP was out of position attacking torpedo bombers, while the relief fighters ready for launch were too late to intercept.

Absolutely, but my argument here compares carrier-based and land-based aircraft in terms of fleet defence, all else being equal. Even with the limitations of pre-radar carrier defence, the carrier was far better placed to respond to a strike than an airbase tens to hundreds of kilometres away.

I would suggest that land-based air not trained to operate in anti-ship missions are overstated in HOi4.

Absolutely* agree - training (in specific operations) had a huge impact on both land and carrier-based air (carrier-based squadrons trained in ASW weren't necessarily as well-placed to undertake strikes on surface warships). Again, I was just talking in general terms, rather than getting into the nitty-gritty. The main thrust of my argument is along the lines of "carrier-based air has intrinsic advantages to defending a fleet relative to land-based air, and greater efficiencies, but land-based air can still put substantial pressure on forces at sea." Were things like functional training included, that should definitely be a factor, at least from my angle .

* Clearly my favourite word today!

 

[Alex_brunius]

Neither the Commonwealth or Germany had aircraft with sufficient range, combat performance and quantity to even attempt it.

How did aircraft lacking range to put efficient CAP over the fleet turn into an advantage in the argument if land based air-cover for fleets could work or not?

And there was nothing wrong with German fighters in terms of combat performance or quantity. Unless I am wrongly informed the most produced fighter all nations all categories during WW2 was the Bf109. Here it is providing air cover for the German battleship Tirpitz in the north sea:

It was done to the extent range allowed for it.

Yes, I get you want to have an exact replay of history, but my central point is that decapitating the CAGs of a carrier group with land based fighters should be a plausible strategy. Don't distract from that.

I agree that it should and I never said anything about that. Being able to use fighters offensively against enemy ships is something completely different than coordinating defensively to provide CAP for your own fleet though!

That might be a limit on biplane relics from WW1, but the range of late and post war aircraft dramatically increases from early WW2 aircraft.

e.g. :
La-11: 2235 km
Mig-15: 2520 km
F-82: 3650 km
P-51H: 2465 km
CF-100: 3200 km
Vautour IIA: 5400 km

Such ranges clearly influenced Soviet thinking into placing a low priority on carriers as land based air could cover much of their needs.

Those ranges listed are from point to point, not combat radius. If you want to use say a Mig-15 ( which is a cold war era plane, not WW2 ) to provide effective CAP for a naval taskforce you want it to be able to spend at least half it's mission time over the fleet. That leaves half the range for getting to and from the target, meaning that the fleet cannot be beyond 2520/4 = 630 km away from your airbase, assuming perfect navigation and zero margins. In practice you probably want to keep the fleet within 500 km of the airbase.

Pre-radar, that is not at all certain, especially against dive-bombers. The Japanese carriers at Midway launching extra fighters to combat the dive bombers failed to get in position in time to disrupt the attacks, while late 1930s Royal Navy thinking assumed that fighters could not intercept attacking bombers in time, and hence lead to powerful AA and armoured decks for those carriers designed for the European theatre. The 1941 attack that crippled Illustrious illustrated the point despite her having radar, the Ju87s were detected only 28 miles away and like Midway the CAP was out of position attacking torpedo bombers, while the relief fighters ready for launch were too late to intercept.

The Japanese Zero needed 5 minutes time to climb to altitude where they could intercept the dive bombers, and they had been launching fighters to reinforce the CAP all morning for 3 hours time as incoming attacks were detected.

Their ability to react had very little to do with lacking performance of the planes, but instead with lacking CAP discipline and radar to spot that an attack even was on the way until it was too late, and with being overwhelmed in general with high number of incoming attacks.

 

[obren]

The Japanese Zero needed 5 minutes time to climb to altitude where they could intercept the dive bombers, and they had been launching fighters to reinforce the CAP all morning for 3 hours time as incoming attacks were detected.

Their ability to react had very little to do with lacking performance of the planes, but instead with lacking CAP discipline and radar to spot that an attack even was on the way until it was too late, and with being overwhelmed in general with high number of incoming attacks.

Actually I agree that the lack of radar was crucial at the battle of Midway. I am not so quick to condemn Japanese carrier operations, in that they were were almost certainly the most highly trained carrier force in the world at the time, and I tend to think that any navy's CAP would have bounced a wave of incoming torpedo bombers and found themselves out of position. It is also rather an unequal comparison to compare the Zero with its excellent performance to the lacklustre climb rate of the Fulmar, however my point was that a pre-radar carrier would find it difficult to stop an incoming raid by launching fighters from the deck, and especially dive-bombers as they attack from a reasonable altitude, which is what happened at Midway and to Illustrious.

In 1941 Illustrious had the most advanced radar outfit at the time, had fighters ready to go and was fitted with 'accelerators', but slow decision-making squandered nine minutes and then another minute was required to turn the ship into the wind. By the time Illustrious started to launch her stand-by fighters the incoming raid was already in visual sight - it then took three minutes before the last fighter was in the air, by which time the attack had started. In the event the Ju87s came in at 12,000ft and the Fulmars could only climb at 1200ft per minute - the Fulmars need 10 minutes to climb to that altitude. They basically squandered the radar advantage.

So a fleet relying on visual lookouts only, even if fully ready to launch fighters including steaming at speed into the wind and even if equipped with a plane as effective as the Zero (that would still require 2.5 minutes before the first fighter could get to the altitude the Ju87s attacked from), still had no realistic chance to disrupt an incoming raid if there was no or insufficient CAP in position. Radar at least gave the defence time to get prepared if they used it to best advantage - which Illustrious did not.

Pre-war RN doctrine was that fleet CAP could not stop incoming raids, partially because they would be overwhelmed by larger numbers of land-based air and partially because of the doctrine that the bomber will always get through, so the carriers need strong AA and armour to survive an attack. Radar changed that balance by giving the defence a real chance to form up fighters and intercept, making CAP much more important. If the Japanese had had Type 79Z radar at Midway, I imagine that the result would have been very different.

Absolutely, but my argument here compares carrier-based and land-based aircraft in terms of fleet defence, all else being equal. Even with the limitations of pre-radar carrier defence, the carrier was far better placed to respond to a strike than an airbase tens to hundreds of kilometres away.

I couldn't agree more. If Indomitable had been with Force Z, then I am pretty sure that things would have gone quite differently - even with Fulmars.

 

[po8crg]

I have been thinking of doing something where CAS is better vs armored targets compared to NAV to give them both a role, but that would require quite a lot of changes to both plane combat and naval combat.

Given that torpedoes from NAV are meant to strike below the waterline and so below the armoured belt, I don't think that would be the ideal approach.

I'd be tempted to try something where CAS (dive bombers) and NAV (torpedo bombers) are separate targets for AA, so the AA has to be split across the two and is less effective when facing both than when facing just one. That's more historically accurate for the reason that fleets used both.

 

[obren]

I have been thinking of doing something where CAS is better vs armored targets compared to NAV to give them both a role, but that would require quite a lot of changes to both plane combat and naval combat.

I would have thought that it would be more the other way around.

The most effective way to sink a heavily armoured and compartmentalised ship was to use torpedoes to either destroy its flotation or to cause it to capsize (consider the US tactics to sink Yamato (attack on one side) vs their attacks on Musashi) (smother the ship from all sides) and the number of hits required to sink the ship). The armoured decks of WWII generation battleships and the British armoured carriers were designed to resist a reasonable sized bomb dropped at altitude, and a dive bomber is essentially just a medium altitude bomber with a better targetting system (ie the pilot adjusting the aircraft itself). Bombs could wreck the ship's fire control and AA capability, rendering it less or non-operational, but sinking the ship was much harder (eg Barracudas attacking Tirptiz), unless you could hit the ship with a really big bomb that could penetrate the main deck - which was generally beyond the dive bombers of the period. Glide bombs essentially made the dive bomber redundant in this role, as a level bomber could guide the bomb on to the target without exposing itself to AA and the bomb could be big enough to penetrate the deck (e,g the attacks on Warspite and Roma).

On the other end of the size scale, a shallower draught vessel such as a destroyer is harder to torpedo due to both its maneuverablity and the greater likelihood that the torpedo would merely pass beneath the ship. A single 500lb bomb hit from a dive bomber could be fatal to a destroyer, as it could knock out the machinery space, or alternatively hot something critical such as a magazine, but in any case could make the ship no longer combat effective.

If you look at the casualty lists, many RN destroyers were lost to torpedoes, but once you eliminate submarine and surface ship launched torpedoes, the numbers are more even. In addition, many ships were hit by bombs that rendered the ship ineffective, but due to control of the sea the RN could get the ship back to port for repair, and came back into service at a later time, so relying on loss statistics by themselves are a little misleading.

In the HOI4 context, I would argue that CAS should be a greater threat to less well protected ships including cruisers, older battleships and merchant ships, but that Naval Bombers should be primarily effective against deeper hulled ships such as capital ships and merchant ships. In any case, medium and heavy bombers should be relatively ineffective due to their inability to hit a target from altitude (at least, until the advent of glide bombs).

 

[Axe99]

In any case, medium and heavy bombers should be relatively ineffective due to their inability to hit a target from altitude (at least, until the advent of glide bombs).

Agree with everything you've posted, and agree with this for level bombing, but medium bombers were often used in a torpedo-bombing role as well (He-111s, SM-79s, Wellingtons and Beauforts, to name the ones I can off the top of my head right now) - as far as I understand and recall (and my head's super-woozy today, so may be screwing this up) in this role they tended to be more similarly effective to a NAV (in HoI4 terms), assuming the unit had appropriate training and equipment.

 

[obren]

Agree with everything you've posted, and agree with this for level bombing, but medium bombers were often used in a torpedo-bombing role as well (He-111s, SM-79s, Wellingtons and Beauforts, to name the ones I can off the top of my head right now) - as far as I understand and recall (and my head's super-woozy today, so may be screwing this up) in this role they tended to be more similarly effective to a NAV (in HoI4 terms), assuming the unit had appropriate training and equipment.

While one can argue regarding whether the Beaufort really belongs in the same category, the He111P6, Sm79./84, Wellington and also the GM4 Betty are all clearly derived from medium bomber technology, but, the case I made in an earlier post was that these torpedo carrying twin engined aircraft are best represented game-wise in HOI4 as land based Naval Bombers. That clarifies the difference between torpedo carrying aircraft attack at low level by specially trained naval strike aircraft from medium level bombing attacks with units that have standard bomber training. Actually, I would prefer the British Naval Bomber 1936 tech to be represented by something like a Wellington rather than a Swordfish, which I would suggest should be a Carrier Naval Bomber operating from the land (like the Japanese aircraft in Taiwan in the 1936 OOB).

 

[Alex_brunius]

While one can argue regarding whether the Beaufort really belongs in the same category, the He111P6, Sm79./84, Wellington and also the GM4 Betty are all clearly derived from medium bomber technology, but, the case I made in an earlier post was that these torpedo carrying twin engined aircraft are best represented game-wise in HOI4 as land based Naval Bombers. That clarifies the difference between torpedo carrying aircraft attack at low level by specially trained naval strike aircraft from medium level bombing attacks with units that have standard bomber training. Actually, I would prefer the British Naval Bomber 1936 tech to be represented by something like a Wellington rather than a Swordfish, which I would suggest should be a Carrier Naval Bomber operating from the land (like the Japanese aircraft in Taiwan in the 1936 OOB).

I think all land based NAV should be medium bombers instead ( and have similair cost & range as TAC ). There are AFAIK no historical examples of single engine land based torpedo bombers that were not also carrier capable.

 

[Captured Joe]

Or have a modified version of TAC (similar to carrier versions of light fighters and such) able to carry torpedoes; I think most existing TACs were historically able to carry torpedoes as well (He 111s and Ju 88s spring to mind), and having planes like the SM79 Sparviero be Italy's TAC would be quite fitting, I think.

 

[marcelo r. r.]

from my tests of 1.7.0, the eastern front is near ok, USRR AI just need more fine tunings on research, focus tree, equipment production. well, perhaps only on next xpac/bugfixes pac.

i run 2 games one without sliders buff and another with +4 stats buff.
I used the same army composition on 2 games.
My only templates are the classic 7x2 INF/ART and for panzer is 4 L.ARM+3 MOT + 2.SPART
Scandinavia front: 48 INF
Eastern front: 192 INF(8armies) and 48(2armies) Light Panzers. , 2 complete fields marshaels with 5 generals each,

i dont use encirclement tatics, i just distribuid the light panzers armies along with frontline, and i use the automated frontlines without micro.

in both runs i started barbarossa in 22/jun/1941

results.
USRR without buffs: wiped almot at JAN/1942. their divisions got eaten fast(overrun) by light panzers, even i dont micro. i endend with surplus of 3k panzers in stockpile.
USRR with +4 bar buff: holding tight, my light panzers gotta destroyed fast, its oct/1941 and im deficit, -3k panzers!

 

[Gort11]

from my tests of 1.7.0, the eastern front is near ok, USRR AI just need more fine tunings on research, focus tree, equipment production. well, perhaps only on next xpac/bugfixes pac.

i run 2 games one without sliders buff and another with +4 stats buff.
I used the same army composition on 2 games.
My only templates are the classic 7x2 INF/ART and for panzer is 4 L.ARM+3 MOT + 2.SPART
Scandinavia front: 48 INF
Eastern front: 192 INF(8armies) and 48(2armies) Light Panzers. , 2 complete fields marshaels with 5 generals each,

i dont use encirclement tatics, i just distribuid the light panzers armies along with frontline, and i use the automated frontlines without micro.

in both runs i started barbarossa in 22/jun/1941

results.
USRR without buffs: wiped almot at JAN/1942. their divisions got eaten fast(overrun) by light panzers, even i dont micro. i endend with surplus of 3k panzers in stockpile.
USRR with +4 bar buff: holding tight, my light panzers gotta destroyed fast, its oct/1941 and im deficit, -3k panzers!

Using exclusively light tanks in Barbarossa is unusual, as is having such huge surpluses and deficits of them.

You should be mainly focusing on medium tanks, and if you have 3000 spare tanks you should be making more divisions. If you have a deficit of 3000 tanks, you should be disbanding some divisions.

 

[obren]

I think all land based NAV should be medium bombers instead ( and have similair cost & range as TAC ). There are AFAIK no historical examples of single engine land based torpedo bombers that were not also carrier capable.

In effect, I am suggesting that NAVs are a medium bomber variant with different weapon fitout and training, to allow representation of the Italian, Japanese and German squadrons that were effective in naval strike. If that suggest was adopted, then I would suggest that developing the tech for a medium bomber should be an alternative pre-requisite for Naval Bomber

Regarding single engine land based torpedo bombers of the period, the RAF had the Vildebeest that was a 1931 single engine biplane torpedo bomber that was land-based only and still in service in reasonable numbers in 1939. It saw service in the European theatre until 1940 and in the Pacific until early 1942. In game terms, you could assume that a 1933 model bomber includes the single engine biplanes of the mid- interwar period, and that the Videbeest is a Naval Bomber variant of one of those.

Or have a modified version of TAC (similar to carrier versions of light fighters and such) able to carry torpedoes; I think most existing TACs were historically able to carry torpedoes as well (He 111s and Ju 88s spring to mind), and having planes like the SM79 Sparviero be Italy's TAC would be quite fitting, I think.

I agree with your reference to TAC. I tend to play HOI4 modded, and when I referred to medium bombers, I should have said Tactical Bombers. I am sorry for not getting the vanilla terminology straight up front.

* * *


In summary, single engine Naval Bombers of the period (with the exception of the Vildebeest) were basically carrier aircraft whether deployed on a carrier or from an airfield, and therefore could be represented by as a Carrier Naval Bommber. Technology wise, they were also essentially a variant of a light bomber that is represented by CAS in the game; whereas the twin engined torpedo bombers used IRL for land based strikes on shipping (eg SM79) were essentially a variant of a medium bomber that is represented by TAC in the game.

As a suggestion to the devs regarding an alternative to the current technology tree design, the modelling of torpedo bomber technologies could be changed to make each of the two quite different torpedo bomber types dependent on a different core technology. A torpedo bomber icon on the Tactical Bomber tech (in a similar manner to the current carrier icons on Fighters and Naval Bombers) could unlock a torpedo bomber variant of a medium bomber (TAC), and the Naval Bomber tech tree could be removed with the carrier based torpedo bombers and instead become a second icon on the CAS tech (representing a variant of a light bomber). You could even go as far as making dive bombers a separate icon variant of CAS as well, thereby better enabling modelling of light bombers such as the A20 and Battle while separating them out from the Ju87 and various carrier based dive bombers.

In a similar vein, if such a change was implemented, then Heavy Fighters might also be moved from the tactical bomber branch to the fighter branch, as the aircraft most typically represented are smaller aircraft such as the Me109 and P-38 and could become a tech that has a pre-requisite of either the CAS or fighter of the respective tech year. If one really wants to represent those medium bombers that were modified as heavy fighters, such as the Ju88 and Blenheim, then why not have a Nightfighter icon on the TAC tech to produce a variant - as such aircraft tended to end up in that role, and specialised aircraft such as the He 219 could then be represented as well.

 

[Leiern83]

Dear Developers

Can u please fix convoys?
Lets say Africa as British that have taken over etiopia: I have been pushed back from Alexandria, but are able to try and retake it from Italy. I have maximized infrastructure and ports, but by some reason the convoy system lets the supplies go to the French ports outside Etiopia, with two in port size and not my own with 10? So all my troops lacks supplies even when all infra is maximized... but all supplies comes to one bad port.

Som why cant i choose my ports? And choose more ports to recive supplies?

 

[Alex_brunius]

Dear Developers

Can u please fix convoys?
Lets say Africa as British that have taken over etiopia: I have been pushed back from Alexandria, but are able to try and retake it from Italy. I have maximized infrastructure and ports, but by some reason the convoy system lets the supplies go to the French ports outside Etiopia, with two in port size and not my own with 10? So all my troops lacks supplies even when all infra is maximized... but all supplies comes to one bad port.

Som why cant i choose my ports? And choose more ports to recive supplies?

Did you block of some seazones from access using the new MtG feature or was your convoys going to the large port raided so it's efficency dropped to nothing? These are the only reasons I know of that can cause the supply system to not use the largest port / best path to send supplies.

Unless there is a valid path for the convoys they cannot make the journey, so either Suez needs to be open or Gibraltar + all zones in the Mediterranean free from raiding to allow supply to flow.