Hearts of Iron IV News

Greetings all!

Today’s dev diary contains the details of a few smaller features coming to the table in No Step Back. In addition, I’ll get ahead of the curve here and point out that there will be no diary next week - we’ll be back the week after with more to see.

[h2]Scorched Earth[/h2]

One of the enduring tactical practices of the Soviet defense during the German invasion, was the use of scorched earth. In No Step Back, you’ll be able to spend Command Power on ordering the strategic disabling of railways in the event of a tactical retreat.

(All visuals WIP!)

Enacted on a state level, every railway present receives full damage, and is immediately flagged, making sure that your eager workers do not attempt repairs.



The pending repairs will show up differently in your construction queue, and won’t be worked on. Rather than re-enable these all manually, you can toggle the state of Scorched Earth off on a state, in the same way it was enabled. All affected railways will begin repairing at once.

Scorched Earth is a pretty simple mechanic here, but has potentially devastating effects on invaders. In addition to the rail conversion time that exists on captured railway, damaged rail must now be repaired in order to continue supply flow onwards. While we considered extending some effects to factories, we determined that this was likely to affect balance far more than we wanted.

[h2]Preferred Tactics[/h2]

We touched on this feature briefly during a previous diary, however, due to some good feedback from the community and from inside the team, we’ve made some alterations to how it works.

Where previously, you set a preferred tactic on a national level, giving a positive chance modifier for that tactic to be chosen in combat, your generals and field marshals will now also possess the ability to earn a favored combat tactic.




At level 5, you’ll be prompted to choose a preferred tactic for your generals. This represents their doctrinal school of war - a choice that affects all units under their command.

Note here, that we are not removing the national preferred tactic, and that the additive weight will compound from national -> field marshal -> general. To pre-empt the question, you can of course stack all 3 as the same tactic, although this drastically reduces your flexibility, and potentially makes it very easy to be countered. The overall additions granted by preferred tactics, have of course been reduced somewhat to account for this.

We wanted to avoid a rock-paper-scissors choice here, and in order to further emulate the core, doctrinal nature of a general’s fighting style, we have chosen to make this choice permanent for characters.

[h2]Strategic Redeployment[/h2]

As we hinted at, strategic redeployment will now make use of railways in order to simulate more realistic army relocation. This applies a different weighting to the regular pathfinder, resulting in choices that largely look sensible where routes of a similar weight are encountered.

Here, we take a train followed by a scenic bus-tour in order to avoid the long connection.



Sometimes it becomes difficult to predict what will be considered 'sensible' in every scenario - there will be edge cases where pretty looking behaviour and logical behaviour do not overlap.

That’s all we have for today’s diary - just a final reminder that next week there will not be a dev diary - tune back in on the 29th!

As usual, I’ll be around to answer questions in the thread below!

/Arheo

[h3]Read in full here[/h3]

Hello there, C0RAX again.

It’s time again to reveal some more secret information that was hinted at in the last dev diary. Specifically this week will be revolving around the final part of railways and trains. So without any more need for introduction here are our stars of the show today.

The railway guns.

So to start off I'll go through how you get a railway gun on the map because it’s a little different to normal land units. First of all you are going to want to research railway guns which comes after armored trains



Then you can find it in your production tab just like building normal equipment. But unlike other equipment you build, these production lines are limited to 5 factories and the railway gun won't be added to your stockpile.



Instead, once completed, your brand new railway gun will appear in your capital, in this way they are built similar to capital ships.



Moving your railway gun is limited to provinces with railways, and so to get to the front you must have a rail connection. Taking into account the rail conversion time when capturing territory is important as you will have to wait for the big guns to be able to help you out.



You can also attach railway guns to armies just like with planes and they will attempt to place themselves relative to the frontline. If you have several, they will be distributed where possible to support your army. There is also a quick select button on the army to select all railways guns attached to an army should you need to.



Finally, the last bit of control understanding is range. Railway guns have a range in which they can support and so from any one point are limited in which provinces they can support. This range is shown by hovering over the unit icon.

On to combat now, here we can see a combat with a supporting railway gun, we have added the useful icon on the combat progress indicator that there is a supporting bombardment. This new icon will also show if there is shore bombardment happening in the combat.



The combat effects of railway gun bombardment work just like shore bombardment, causing negative combat stat modifiers to those on the receiving end of the big guns. These modifiers affect both soft and hard attack as well as defence values. Notably, these effects do not stack - it becomes more important to spread out your railway artillery than to concentrate it.



Finally we need to talk about capture and damage, railway guns can be captured via encircling them and damaged by damaging the railway they are placed upon.

Now railway guns are the biggest guns by far used on land and so it's important that we have representations of those built by the major powers. So now we look at the unique guns for the major powers.

This is the german Schwerer Gustav model you will see when playing as the germans. It's perhaps the most famous railway gun and definitely the biggest and so had to have a part in this feature.



This is the BL 9.2inch railway gun, a relic of the first world war but these big guns were kept in service until 1945.



Following that we have the french Canon de 305 another veteran of the first world war.


Next up is the USA’s 8-inch Mk. VI which remarkably first entered service as late as 1941!


Type 90 240 mm railway gun whose claim to fame is being destroyed by the retreating Japanese in the soviet invasion manchuria.

And finally the TM-3-12, three of these were made in 1938 and were used in the winter war against finland, unbelievably these where in service until 1999 (a whopping 61 years of service)

Finally here's a cool clip of the Schwerer Gustav firing in game.


[h3]Read the full Article Here [/h3]

Greetings, and welcome back for our last look at the supply system that ships with the Barbarossa update. As you all know, I’m British, and in Britain the trains never run on time - I couldn’t possibly break with this tradition, hence a completely intentional 10 minute delay on today’s diary.

There’ve been a couple of changes since we last looked at this, so you may find I’ll be reiterating a few aspects that we’ve already covered in previous diaries, albeit in some cases with a new twist.

Trains

As indicated in a previous diary, the logistics network that supplies your troops relies on the large-scale relocation of supply using trucks and trains.

Whereas trucks serve as an optional last-mile carrier for military supplies, trains make up the backbone of any logistics network that supplies an army which exceeds the local state supply available in its location.

The domestic production of trains is something that is unlocked via the technology tree. Many countries will start with the initial (civilian) train technology readily unlocked, however, there are several more options available to you as time progresses (more on this below!).

Your overall train need for the logistics network is derived from the overall supply usage of the nodes supplying your troops, and the distance factor that supply has to travel in order to reach them. In essence, the more troops you have drawing supply, the more trains you will need to keep supply running.

Needless to say, if fewer trains are provided than are required, supply output at point of demand will incur penalties proportional to the magnitude of the shortfall.

In one of our previous diaries, we alluded to a number of interactions that could be performed on supply nodes - one of these was a train priority setting. It transpired that this did not fit well with the underlying simulation, and we’ve removed this setting from nodes.

Logistics Strike

Of course, a freight-train loaded with supply makes a juicy target for the enemy. In NSB, CAS and bombers are able to perform the new logistics strike mission, which can put a severe strain on an enemy’s ability to supply their network - actively destroying trains and trucks, as well as damaging railways in the target area.

The strategic bombing air mission will also target rail and supply infrastructure, however the logistics strike mission is a much more effective way of neutralizing an enemy’s fighting capabilities while retaining important industrial infrastructure if you intend to occupy an area for any period of time.
Train Variants

As mentioned above, trains will be a researchable technology with several variants. Trains, unlike regular units, are not controllable - their movement and behaviour is entirely simulated based on the needs of your logistics flow. This said, there are several important statistical aspects to them.

To begin with, most of your network is likely to be populated by civilian trains. You can construct more of these by co-opting military factories. Further on in your campaign, you can unlock a variant of the civilian train with a significantly reduced construction cost.

To combat the strategic mission mentioned above, there is one (or..is it more?) further item in your toolbox for owners of the NSB expansion. Armored trains, while coming with a higher price tag, are much more resistant to destruction from air missions, and can act as an effective deterrent against logistics disruption.

Train enthusiasts (we have none of those here, right?) will note that the trains displayed above belong to the soviet union - there is indeed unique art as well as 3d models for several other major nations.
A highly camouflaged train in action. Displayed trains are based on your stockpiled train equipment. This is the german armoured locomotive!

That’s all from me for today - I’ll hand over here to @YaBoy_Bobby to go over some of the details on supply distribution at a hub level:

Hub to Province Supply Distribution

We have talked about how trains and rails feed the supply hubs, but not so much about how hubs feed divisions in the field. As hubs are fed from the capital province by a rail network, divisions are fed by hubs over land.

Every Hub has an overland range that gives it a collection of provinces that it touches. This range is constant, but the cost of moving over each province is impacted by things like weather, terrain, rivers, and infrastructure. Motorization decreases the penalty for crossing each province, thus increasing the number of provinces a hub will touch and potentially creating greater hub density and thus greater overall supply in an area.

As has been alluded to with the phrase “hub density,” a province may be touched by multiple hubs. When multiple hubs touch a province, a ratio is created to determine what percentage of the supply requested each hub is responsible for. Every hub that touches a province lessens the supply burden of other hubs also touching the province.

In the final step, Divisions draw supply from hubs, depending upon the relationship between their current province and the hubs that touch that province. When a hub does not have enough supply to meet demands, the lack of supply is distributed evenly across all divisions currently drawing from the hub.

In older DDs we talked about a penalty to the amount of supply delivered to a province based upon weather, terrain, and distance. Over the summer we decided to remove this penalty as we found it compounded in a hard to predict way that created bad supply and sometimes penalized having more hubs touching a province in a way that we did not like.