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...
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 Alpha.
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: Paradoxian.org
Note that while the mod's TFH version is currently in an early alpha release, you can still play the mod's FTM 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.
A new beta version of the mod is now available from the downloads section. Some database issues were fixed along with a bunch of AI adjustments. 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. Please note that you should delete any previous install of the mod and save games, as this version is not save-game compatible with the previous TFH versions.
The main changes revolve around database fixes, localization (in-game text) fixes, AI adjustments, and a buggy few events and decisions were fixed. Also included is a an experimental OOB for Japan and Manchukuo, where the Imperial Manchukuo Army is modeled as an expeditionary force under Japanese command. This models history better, and we hope it will improve the Japanese land AI's performance. By "improve" we mean "perform worse in a historical manner for balance reasons", because AI Japan is a real beast now and is doing way, way better than it did in the mod's FTM version.
The mod is now in a beta state and we expect there to be 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 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.