Just Cause Wiki
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Modifying or modding is the changing of the files that make up the games, in order to change the game content (vehicles, weapons and just about anything else).

A modified Mullen Skeeter Eagle with rockets and miniguns at the Pelabuhan Saudagar Harbor. The helicopter is usually unarmed.

Quotes from game developers

"The modding community has always been something spectacular in all games and any game that gets the love of the modding community is already in a good spot. A game that's all about the sandbox - really in a good spot." - An unidentified developer for Just Cause 3. Needs identification (the video interview may be on the JC3 article).
"Everyone here at Avalanche loves the modding community. A lot of us came from the modding community, so there's a lot of will to help it out. Umm... we would love people to continue modding Avalanche games. We think it's an homage to when people are willing to spend their personal time to come up with awesome and crazy ideas and build incredible new systems." - Roland Lesterlin, JC3 game director, in some JC3-related interview.
"We have taken inspiration from some of the mods, that were produced for Just Cause 2, for some of the more crazy ideas that we've put into Just Cause 3" - An unidentified developer for JC3, in the third part of the "developer diary" promotional video series for JC3.
"The modding community took - and it's a complex piece of code - so the fact that people were able to get in there and do what they've been able to do... is really cool. I mean, watching a lot of the mods, I mean, the famous ones, the Superman mods, the infinite grapple mods... You know, the multiplayer guys coming out, trying to figure out how to run the game on a server. All that's an incredible thing to do as modding and some of these guys worked on mods for years to get them to work and that sort of dedication to a game... You have a responsibility to put out a game that allows them to do it again. So I kind of can't wait to see what people do now that we've expanded the toolset so much." - Roland Lesterlin, JC3 game director, in the third part of the "developer diary" promotional video series for JC3.

Legal notice

  • Most modifications require the installation of third party software.
    • There is no way to be sure if the files you download and/or install will work at all, or if they will turn out to be a computer virus. It is therefore suggested to scan the downloaded files with trusted anti-malware software.
  • Proceed at your own risk.
    • The Just Cause Wiki will not take any responsibility for any damage to your game; your gaming device, or any legal action that might be taken against you as a result of any end-user license agreement violation.
    • The content of this article has not been verified by anyone who could take responsibility for damage to your game, or gaming device.
  • Definitions for the purposes of this notice.
    • "Modifying the game" is hereby defined as (but not limited to) the following:
      • Changing and/or replacing any of the files that make up the game.
      • Inserting any files into the games file directory.
    • "Third party software" is hereby defined as files (or code) that was made by someone other than the company that made the game.
    • "Gaming device" is hereby defined as any electronic equipment that may be needed to play the game. Examples include and are not limited to: PC; Xbox and PlayStation.

Purpose and mod types

It's not that the games wouldn't be fun as they are, but people can always think of ways to improve things. Some improvements might be considered fun by some and terrible by others, so it's all a matter of taste.

Some examples of the most common mods (JC2):

  • Black Market mods are very commonly used.
    • They change the prices of things (usually to $0).
    • Let one "buy" (spawn) almost any vehicle that can be seen in the game.
    • Shut up the black market dealer.
  • Vehicle weapons. It's possible to add any of the existing kind of Miniguns and helicopter rocket-launchers to any vehicle.
    • One example is a mod that has added multiple of both to the Pocumtuck Nomad (Agency RV).
    • Another example is a mod that has added multiple different weapons to the H-62 Quapaw transport helicopter to turn it into a heavy attack helicopter.
  • Vehicle statistics and handling. It's possible to make vehicles lighter/heavier, faster/slower, be able to drive up very steep hills (and walls), bullet proof, explosion proof and more.
  • Hand held weapons can also be made more powerful.
  • The Protec Grappler G3 can be improved so the cable would reach to several kilometers and so that the double-grapple cable would be unbreakable (to allow the towing of heavier objects).
  • The character model can be replaced to make Rico look different, or pretty much be a different person.
  • The game environment can be changed to add new islands and roads. This takes a very large amount of work, so large mods like that are relatively rare.
  • Gameplay can be changed to make the factions fight each-other and/or to make the Panau Military stop fighting you. It's also possible to make it so that the military only uses Happy Bubble Blasters.

Just Cause


It is disappointing that Eidos has not included any SDK for its community. However, there have been ways to extract their archives. This article documents as much JC-related modding as possible.


Thanks to the MultiEx community and QuickBMS, extracting the *.ARC files has been made possible.

First, locate the folder containing your game Archives. (Its named should be named Archives, for obvious reasons.) Create a new text (.txt) file in that folder, then paste the following code in it:

for i = 1 < 0xFFFF
get NSIZE long
getdstring name nsize
get offset long
get size long
if NSIZE == 0
log name offset size
next i

Save the file.

Now download QuickBMS, and extract it to your Desktop. You may delete the src folder if you want. Double click on quickbms.exe, then for the first part, select the text file you created. For the next part, select one of the archives, from pc1.arc to pc4.arc. Then create another folder to save the extracted content to. Hit "OK", then once it is finished, you have now extracted the content from the game!


This is an Archive. QuickBMS, along with the script included above, are able to open most of them. (Note that pc0.arc cannot be opened with the above script.)

As a reference, these are the first 4 bytes (headers) in the 5 archive files normally included with Just Cause:

File Name Header
pc0.arc 4C 00 00 00
pc1.arc 04 00 00 00
pc2.arc 04 00 00 00
pc3.arc 04 00 00 00
pc4.arc 04 00 00 00

In fact, pc0 is most likely unopenable due to its unusual header. That, or the header could be indicating a different file format, with which will need a new script.


Stands for Direct Draw Surface. These files are used with DirectX to apply textures to models. Paint.NET has a plugin if you are looking to convert these to a normal format.

Main article: DirectDraw Surface.


Still an unknown acronym, these files appear to control how NPCs function. Acronym may stand for "Binary Finite-State Machine" as FSM's are quite common with NPC programming.


Normally standing for Level Of Detail, these files could be the actual models, containing actual point-by-point info, as well as animations.

Main article: Level Of Detail.

List of the only known JC1 mods

  • Two trainers can be downloaded here.
  • See Myths for the unfinished superman mod that doesn't seem to exist anymore.
  • This link leads to a Cheat Engine script which allows to spawn any vehicle with any faction colors and symbols, as well as repaint already existing ones. The video in the end of the page explains how to use it properly.

See Also

A Xentax wiki page on Just Cause's ARC file format.

Just Cause 2

Using "dropzone"

In order to use these, you create a folder in your game directory called dropzone.

In x64 versions of Windows:
C:\Program Files\Just Cause 2\dropzone
C:\Program Files\Steam\steamapps\common\just cause 2\dropzone

In x86 versions of Windows:
C:\Program Files (x86)\Just Cause 2\dropzone
C:\Program Files (x86)\Steam\steamapps\common\just cause 2\dropzone

Any files placed inside the dropzone directory will override most game content. It is where your mod files should go while creating, tweaking, and testing them. Once the files are placed in there, you're good to go! From there, you can start making your own mods if you want to get that in depth. See Current Tools to get the latest and greatest tools and documentation of each.

If you want to redistribute your mod, the easy way to create an .arc/.tab file set is to run the game, then look at the dropzone directory -- you will see separate_files.arc and separate_files.tab, simply copy those elsewhere and rename them appropriate. Be sure you only have your mod files that you want to include in separate_files.arc / separate_files.tab in the dropzone directory at the time, though. Note that the game removes those files when it exits so you need to copy them after the game has started up.

Bin Editing Information

These links include information on how to edit specific bin files. (using XML to change contents of course)

Field of View

It is possible to modify one's field of view. Here are the steps:

  • 1: Right-click Just Cause 2 in your Game Library.
  • 2: Select 'Properties'.
  • 3: In the General tab, select 'Set Runtime Options...'
  • 4: Type in '/fovfactor=x' (without the 's), with x being a number from 1.0 to 2.0 (2.0 giving the highest field of view, 1.0 being the default).
  • 5: Select OK. You can now start the game with an enhanced field of view.

It is unknown if the same can be achieved in console versions of the game.


See also

Get mods

Just Cause 3

Just Cause 4

How it works

Just Cause 4 mods normally change the game by inserting files into the game's root directory to replace/overwrite the game's original files.

Most mods require a program called a "mod loader" (which automatically runs the game with the mods installed) and a "dropzone" folder to function. Mod loaders can be obtained on the same sites where mods are distributed. The mod loader creates a folder commonly called a "dropzone". Downloaded mods are normally compressed/zipped, so they have to be extracted/unpacked. The files can then be either added to the game manually, or inserted into the dropzone folder (usually the latter, in most cases). When the game is played, rather than running the game from the original game files, the mod loader implements the files in the dropzone into the program.

Obtaining mods

  • videogamemods.com - The largest JC4 modding site, with ~100 downloadable mods, give or take. Most mods on this website require the use of mod loaders and dropzone folders. It is suggested to use mods from this website if you're new to modding. When compared to other mods, mods on this site are relatively simple and easy to install.
  • Unlike Just Cause 2 and 3, Just Cause 4 will not have an official multiplayer mod, and will probably never have any sort of multiplayer mod.
  • Modding tools for JC4 can be obtained here.
  • A different set of tools is here.
  • A relatively simple and easy "mod creator" (converts EE files into readable XML, and vise versa) can be found here. Once again, it's suggested to use this mod creator if you're new to modding since it's relatively easy to use. However, keep in mind that its modding capabilities are comparably very limited, and can only change the values of some variables and factors, eg. the damage of a certain weapon, or the top speed of a certain vehicle.

Maximizing animation and cinematic content workflows for JC4

"Maximizing animation and cinematic content workflows for JC4" is a 102 page PDF, written by Brian Venisky, senior technical animator at Avalanche Studios. The PDF likely contains some information that could be relevant to modding JC4, or at least for modders to better understand the game.

Unfortunately we can not upload a file that large directly onto the wiki, but here's a link.

Additional trivial notes

  • Using the "Ashen Mod Tools" to poke around the game files has revealed that when converted into human-readable XML, some files reference phrases like "unstuntify", "is bike stunting", and "is fake stunting". It's not known what this is about, but it likely has something to do with in-game stunts, or freeroam stunts.
    • As an example, Rico says special dialogue cues when he puts balloons and thrusters on cars. This means that the game has some sort of method to detect (or at least determine) whether the player is "stunting"; as such, it is reasonable to assume that these phrases are related to this.

See also


Just Cause 2

Just Cause 3

Just Cause 4