Today i will show you how to get started with modding Just Cause 3 and 4, as well as give you a general overview over common filetypes!

Before we start, if you want to do any texture modding, you will be needing either Photoshop or Paint.net: https://www.getpaint.net/download.html#download

You will also be needing Notepad++: https://notepad-plus-plus.org/downloads/

And finally, also get the HXD hex editor: https://mh-nexus.de/en/downloads.php?product=HxD20

To start off with Just Cause 3, you will need to download two sets of tools:

Neam’s modified modding tools: https://justcause3mods.com/mods/modified-gibbeds-tools/

UnknownMiscreant’s enhanced modding tools: https://cdn.discordapp.com/attachments/533266187904090112/638390704498016276/jc3tools.7z

Both of these tools are going to serve certain purposes. Naem’s tools will be used for stat files, that i will elaborate on later. Unknown’s will be used for anything else

To start things off for Just Cause 4, you will also need two sets of tools:

Unknown’s ashen mod tools: https://justcause4mods.com/mods/ashen-mod-tools-for-jc4/

Predatorcz’s Apex modding toolset:

https://justcause4mods.com/mods/apex-modding-toolset/

Addionally, download this file and unpack it, you will get four .shs files. These go to [jc4 tools folder]/resources/filelists: https://cdn.discordapp.com/attachments/533266187904090112/659890602921426964/FileLists.7z

These are used for the tools to be able to unpack dlc files

Here, we use unknown’s tools for pretty much everything, the apex toolset is only used for textures

After you download those, unpack them and put them into the root of a hard drive, or any other filepath that is as short as possible

Unpacking files:

Now, go into unknown’s tools and run unpack.exe. A command window will open up, prompting you to enter the filepath to either game. Go to the game’s install location and copy the filepath at the top of the explorer as text and paste it with a left-click and hit enter. Now you will be asked to enter an output location, this will be the folder all the files will be stored. Create a folder in the root of a drive with at least 90 GB of free space, copy the location, paste it in and hit enter. The majority of the game’s files will now be unpacked into your output folder

This process will take some time, depending on the speed of your storage device, mind that during the unpack, everything on that drive will slow down a lot, due to all the file-transfer

For Just Cause 3 you will end up with several folders. Those are win_64, patch win_64 and dlc, move the folders from win_64 , like editor and locations to the unpack’s root, then the ones in dlc and patch. this will simplify things a ton later

For Just Cause 4 you will end up with folders like boot, patch, main etc. First, go into all the folders without a _patch behind them and copy all the folders into the unpack root. after all that’s moved, now move the contents of the patch folder to the root of the unpack, replace files if prompted. Here too, we get a dlc folder, move all the folders in it to the root as well

This will give us a organized and clean setup with a 1:1 representation of the game’s file-structure and will help us understand the purpose of these folders

We will now have something that looks like this for Just Cause 3:

And this for Just Cause 4:

That is all for the setup process, congrats!

Now to explaining all these folders:

__UNKNOWN contains files, that the unpacker was not able to identify and dehash their names. Dehashing is important us since it will make editing things a lot easier. Dehashing a file-name can lead us from 4F69B9FF to v0200_car_capstone_apc_rebel_01, which is a lot easier to work with

accomplishments, ai and animations are pretty self explaining

I don’t even know what the one file in asynchronous does

Cerbus has security files

Climate controls various climate zone assets, like far away textures of nature elements, close by models and their textures

Editor houses game objects, rico, npcs, weapons and vehicles

Effects is self explaining

Environment has has data about different weathers, like rain, thunderstorm, etc

Global has all kinds of stuff, the important factor with this folder is, these files are loaded at all times and do never refresh, so modifying them requires a game restart

Graphs has paths about how certain events, like parts of mission play out

Locations contains all files for cities, villages, some files or rico and even mission files

Models contains every model, as well as high res textures for close by

Missions houses a list of all missions

Online has files of online activities like feat scores

Profile has files for the menu layout

Scripts has various scripts, like cameras

Settings files also do not refresh and consist of mostly lists, like an list of all weapons, vehicles, NPCs, objects etc. If something is not listed in here, the game will not spawn it whatsoever

Sound, terrain, test, text, textures, ui and videos are self explaining

Just Cause 4 got a few more, but most of them are self explaining. One that is not, is packages. This one houses the most hated file in all of JC4 modding, generated_global_resources.bl. This file has all stat files of any vehicle in it, which means only one vehicle mod at a time could be installed, luckily, modding god Protato made a fix for this, the vehicles edits mod. It has all vehicle files with their stat files in their actual files, like it is in jc3, which allows for mod to be compatible with eachother and no headache for the modder. You can find these files here: https://justcause4mods.com/mods/vehicle-edits/

You should always use these files as base for any vehicle/weapon mod, as they do not only make your life while modding 100 times easier, but also enable nitrous and turbojump for every vehicle. Little heads up though, do never use v908_trailer_agencysmallmobileweapon in dlc\agency\editor\entities\vehicles\01_land as this was accidentally left in and will crash your game when going near an agency submarine

With all this said, let’s go over what you will be facing when looking through these folder, a ton of filetypes you never saw in your entire life:

.ee, .bl, .fl, .nl – These are archives, like zip files, and contain all kinds of files, like models, low res textures for far away, stat files and more. These are unpacked with Smallunpack.exe for JC3 and StreamedArchive.exe for JC4. You repack them with Smallpack.exe for JC3 and StreamedArchive .exe for JC4. When unpacking them you will get a folder with all files in them. To repack, drag the folder on the tool of the game you’re modding. These formats are referred to as AAF, or Avalanche Archive Format. ee is used for vehicles, weapons and other stuff in the editor folder. bl, fl and nl is used for locations, where nl stands for near locations and fl for far location

.epe, .blo – These are the “brain” of an archive and puzzle together the contents of the archive they belong to. epes are used by stuff in editor, blos for lcoations. You unpack and repack them with ConvertProperty.exe for JC3 and PropertyContainer.exe for JC4. These files do a lot more than just puzzle together things, they can also be used for weaponizing and component swapping, say water interaction

ddsc – These are mostly low res textures and can be unpacked with ConvertTexture.exe for JC3 and JC4. On unpack you will get a dds, that can be opened by Photoshop and Paint.net as well as an xml, once you’re done editing, drag the xml onto ConvertTexture and it will repack into a ddsc

hmddsc/atx1 – These are high res textures, where hmddsc is used in JC3 an ATX1 in JC4. These are…special, as they need to be unpacked over their low res counterpart. To unpack an hmddc, find it’s ddsc counterpart and put them in the same folder. Now drag the ddsc onto ConvertTexture, this will also give you a dds file and an xml, however the dds will now have the high res texture. After editing, drag the xml onto ConvertTexture again, and the tool will repack that into both hmddsc and ddsc. JC4 requires the use of the Apex toolset for most high res textures. I woll go into more detail on texture modding in a future tutorial

vmodc/wtunec – These are stat files, containing stuff like fire rate, magazine size, nitro duration, etc. These are unpacked and repacked with Batch.exe for JC3 and AvalancheData.exe for JC4 and are referred to as adf files. For JC3 modding, these are the only files that need to be un- and repacked with naem’s tools, as unknown’s set every value to zero on repack due to a bug in those tools

toc – These won’t be used by the majority of people that just seek to modify weapons. They are exclusive to JC3 and link to patch files outside of the ee/bl/nl/fl files and are needed if you want to add files to an archive. They do not contain any files, only a filelist

These are the most important filetypes you will come across sooner or later. I hope this introduction is not too long and will help some of you getting into modding Just Cause games!

Now that you know most of the filetypes and how to deal with them, feel free to mess around already and look into some of them or just explore to search for things you are interested in. More tutorials will follow soon!

If you already have questions, feel free to ask me! You will find me at https://Discordapp.com/invite/efherxs