The Historical Plausibility Project is a mod for Hearts of Iron 3 and its expansions with the goal of helping the game reach its full potential as a half-historical / half-sandbox game.  The mod features a vastly improved AI, historical OOBs for every nation, complex internal politics, a reworked leadership system, HOI2-style doctrines, capital ship modernizations, over 6,000 unique unit pictures, and much more.  The HPP has complete versions compatible with HOI3, Semper Fi, and For the Motherland.  The initial Their Finest Hour version is currently available for download as an unfinished beta.  The mod will remain in the beta state until the mod team decides to stop working on it or a new expansion comes out, so don't let the term beta fool you.  All versions of the mod are working, and the TFH version is currently in the bug-fix and new-feature-adding stage.

The HPP is the result of the efforts of the HPP team's five members of Slan, TheBromgrev, TZoli, SSmith, and Nephandus from the ParadoxPlaza forum, and its main forum is its official ParadoxPlaza forum, which Paradox requires proof of game ownership to enter.  The HPP's forum contains the mod's FAQ, Submod downloads, country guides, and small hotfixes.  In addition, part of the mod's previous work to the East Asia part of the map is now in the Their Finest Hour base game for everyone to enjoy.

The mod's download files are split into two parts:  the mod's core files and an optional graphics pack.  The mod uses HOI3's built-in mod folder, so it will not work with JSGME or any other generic mod enabler, and the mod cannot be copied over the base game files.  The mod folder must be used.  Detailed install instructions are found in the downloads for each version of the mod.

Several submods exist for the HPP.  Among them are alternative counters, an Austria-Hungary mod, and an AI adjustment submod.  Since not all of the submods were created by the HPP team, for now they can only be downloaded from the HPP's forum.  Also, the following link will take you to the HOI3 Wiki's list of HPP Let's Plays:

Note that while the mod's TFH version is currently in an early beta release, you can still play the mod's FTM version if you have the TFH expansion.  Older releases for previous HOI3 expansions are available here as downloads as well, but are not supported (aka we won't fix any bugs).  The FtM download has install instructions that explain how to install the mod if you have either FtM or TFH.

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0 comments by thebromgrev on Mar 3rd, 2014

A new version of the mod is now available from the downloads section. The focus of this version was to fix bugs, adjust the Trade AI, add a Gurkha unit for the UK and Nepal, adjust naval firing ranges, and add a decision for Japan to deal with the surrender of the UK. We've been able to get to 1946 without crashes in our hands-off tests, so the mod is now in an unfinished beta state. Full changelog is in the download.

HPP TFH version 3.2.7 (09 July, 2013)

The main new features are Gurkhas and some naval rebalance.  Gurkhas can only be recruited by nations that either own a Nepalese core or are Nepal's puppet master.  This means that the UK and Nepal can recruit these jungle/mountain troop units right away, but other nations can do so as well if they conquer or puppet Nepal.  Naval firing distances have been lowered to more historical values, air defense and attack has been improved for ships, and destroyers are slightly less effective at finding submarines.

Also included are trade AI improvements based on player feedback.  Nations are more likely to trade with land-locked neighbors, and the major raw material exporters are more likely to sell rares.

If you have 4GB of RAM or more, have a 64-bit OS, and are getting CTDs, then you need to download Podcat's LAA .exe from the official Paradox Tech Support Forum or apply a 4GB patch!  The game as-is can only use 2 GB of RAM, so the CTDs you're seeing come from the game running out of memory!

The mod is now in a beta state and we expect there to be some bugs, but no crashes.  If you follow the install instructions to the letter then it will start up without any problems; I'm testing with the exact same download you guys will get and I follow the instructions I wrote down in the download section and can start up the mod with no problems, so if you're getting startup issues then go double-check the install instructions.  Once the game starts though, there may be buggy AI behavior due to TFH changes to the AI system from the FTM expansion.  If you get a crash or see the AI fall asleep or build/research something silly then please comment here, in the ModDB forum for the HPP (check out the forum link to the upper-right, next to images), or the mod's main forum (official page in the mod's profile to the right) telling us what happened.  The more detail you can provide the faster we can fix the bug or crash.

For trade, diplomacy, and production AI-related bugs, it would help tremendously if after you quit the game you would go to the folder Documents\Paradox Interactive\Hearts of Iron III\HPP\logs, open the file system.log in notepad or some other editor, and check the bottom of the file for errors.  This file is deleted every time you start the game, so please look at it and report any errors at the bottom before you start the game up again if you saw the AI fall asleep.  If you do see any errors please report them, because the errors will point us to the files we need to fix.

Also, please keep in mind that generating the map cache can take a long time and hog up a bunch of memory.  If you have an older computer, you may want to go to Documents\Paradox Interactive\Hearts of Iron III\map and copy your vanilla cache folder to Documents\Paradox Interactive\Hearts of Iron III\HPP\map (make this folder if it doesn't exist).  This will bypass the map cache generation.  You'll lose out on the visual region changes (the thick black borders on the map), but nothing else.

Known issues:
*Game will crash if you try to view strategic resources in the statistics screen.
*unit-limiting strategic resources not implemented
*lend-lease, licensed builds, and the new spy system aren't fully implemented yet. SSmith can correct me if I'm wrong
*When the UK surrenders, not all nations will stop being at war.  The outcome is fairly random, which makes it hard to figure out why some countries that get kicked out of the Allies end their war with the Axis and some don't, and the nations that get kicked out vary even if you save and reload.  We're looking into a solution.

NOT bugs:
*Anything you also see in the base game is obviously a base game problem.  I'm talking about stuff like the music stops playing, the interface disappears, supply system is stupid, allied nations do nothing, etc.  Things like missing cores, AI not researching infantry techs, and events not working are mod-related bugs.  Basically, if you see an issue related to the interface not looking right, music/sounds not playing correctly, or what the AI does on the map, it has nothing to do with the mod since those areas are hard-coded.
*If pictures are missing or wrong, then you didn't install the graphics pack from the addons section.
*If the mod doesn't start up, then you didn't follow the install instruction
*France has been coded to declare war on Germany once Germany's threat gets too high.  This can happen as early as 1938 if Germany is too aggressive or allows spies to raise its threat.

Downloads RSS Feed Latest Downloads
HPP TFH version 3.3.3 (08 April, 2014)

HPP TFH version 3.3.3 (08 April, 2014)

Apr 16, 2013 Full Version 130 comments

Latest full version of the mod, compatible with Their Finest Hour 4.02. The forum hosted on ModDB has a list of known bugs and issues. When you start...

HPP V2.0 Manual

HPP V2.0 Manual

Dec 2, 2012 Other 0 comments

This is the manual for the final Hearts of Iron 3: Semper Fi v2.04 version of the mod, and is only accurate for that version. Separate manuals are available...

HPP V1.0 Manual

HPP V1.0 Manual

Dec 2, 2012 Other 0 comments

This is the manual for the final Hearts of Iron 3 v1.4 version of the mod, and is only accurate for that version. Separate manuals are available for the...

HPP HOI3 Final Version V1.0

HPP HOI3 Final Version V1.0

Jul 9, 2012 Full Version 0 comments

This version of the mod is the final HOI3 1.4-compatible version. It is not compatible with any of the expansions. A pdf manual that summarizes the major...

HPP Semper Fi Final Version V2.0

HPP Semper Fi Final Version V2.0

Jul 9, 2012 Full Version 0 comments

This version of the mod is the final Semper Fi-compatible version. It is not compatible with HOI3 1.4 or HOI3:FtM 3.0 or later. A pdf manual that summarizes...

HPP FtM Version V3.0.0 (17 March 2013)

HPP FtM Version V3.0.0 (17 March 2013)

Jul 9, 2012 Full Version 34 comments

Latest full version of the mod, compatible with For the Motherland 3.05 or 3.06 only (if you have TFH, you can still play this mod, but you won't see...

Post comment Comments  (0 - 10 of 158)
henry1014001 Apr 10 2014, 2:49pm says:

Brilliant mod thank you

+1 vote     reply to comment
Testosticor Feb 15 2014, 5:56pm says:

I just had an idea for a new kind of war goal. It would be a special one only usable against the Spanish State. The war goal would simply restore the Spanish Republic. This could be accomplished with a conquer goal and then releasing them as a puppet but since Spain doesn't have claims on all of its original provinces sticking the conqueror with tiny pieces of useless land in Africa.

+2 votes     reply to comment
Guest Feb 13 2014, 4:11pm says:

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thebromgrev Feb 14 2014, 4:51pm replied:

1) The mod goes to 1948.
2) Depends on what you mean by "playable". Minor nations are minor for a reason. Most of them have more LS than the base game though. If you're expecting to be able to conquer the world as Hungary, then a mod about plausibility won't be for you.

+1 vote     reply to comment
Testosticor Feb 8 2014, 11:04am replied:

Oh it's not their unites. It's my original units.

+1 vote     reply to comment
thebromgrev Feb 8 2014, 11:46am replied:

Then the only thing I can think of that would cause what you said is if you or the AI in command of your armies adjusted the theater HQs. Nothing in those events touches the USSR's OOBs. All that happens is that you get 75% of each Baltic State's military, and the game engine decides at random what you get. The units you receive won't be attached to a command hierarchy, but your own units won't be affected at all.

+1 vote     reply to comment
Testosticor Feb 8 2014, 7:25pm replied:

Well for some reason they always are. I've tried it with and without AI control and the same thing happens each time. I've even triggered the event early to ensure that's what causing it and it seems to be. Also is there anyway to keep AI from messing with theaters? I keep my theaters on AI control when I'm not at war because it's easier to keep track of what units are needed that way. I'll look away for a couple minutes and One theater has completely absorbed another and a new theater has been created somewhere that doesn't make any sense. This can get to be pretty annoying.

+1 vote     reply to comment
thebromgrev Feb 9 2014, 6:27pm replied:

Don't let the AI control your HQ structure :P Pretty obvious :) There's a green button that lets the AI command your units. Once you click it, another button appears that, if you click the new button, will let the AI reorganize your HQ structure. Don't click the second button and the AI won't be allowed to reorganize your HQs.

+1 vote     reply to comment
Testosticor Feb 13 2014, 2:40pm replied:

I don't think I had hit that second button but I could be wrong. I'll see if that's it or there's some other problem and get back to you.

+1 vote     reply to comment
Testosticor Feb 13 2014, 4:43pm replied:

I gave it a try and this time I know for sure the AI was not in control of my HQ structure and it still happened. All the time. Almost every week there was a new HQ in just the dumbest place. Eventually the AI had enough of that and combined it all into one HQ spanning the entire country which didn't work out so well in a two front war. I don't think it's a problem with HPP because this exact same thing happens in vanilla. If there's anyway to stop this from happening I would be very interested in learning how.

+1 vote     reply to comment
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Hearts of Iron III: Their Finest Hour Icon
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Released Jun 1, 2010
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