Post tutorial RSS How to Make new Weapons with MW4 Mod Tools

DISCLAIMER! This tutorial might be incomplete and may not work as intended. MAKE BACKUPS! This guide will help you create your own weapons for MW4. This information can also can be used to modify existing weapons.

Posted by on - Intermediate Other

DISCLAIMER! This tutorial might be incomplete and may not work as intended. MAKE BACKUPS!

This guide will help you create your own weapons for MW4. This information can also can be used to modify existing weapons.

Prologue - Setup

before you can mod anything, you need your tools ready. For starters download the Mechwarrior 4 mod tools from here at Moddb.

Now my preferred setup is to have the game installed in primary directory, no subfolders, helps speed things up. As my personal example that would place its directory under C:\Mechwarrior 4 Mercenaries. To make things even more streamlined, i installed the mod tools directly in the Mechwarrior directory under C:\Mechwarrior 4 Mercenaries\Mech_tools.

Step1: Extract EVERYTING

well, not everything, but there's a lot.

open MW4eXtractor.exe click the open button and select core.mw4 and props.mw4 under C:\Mechwarrior 4 Mercenaries\RESOURCE (in separate instances, not at the same time.) once open check Use ID Names and with core or props.mw4 selected and press Extract it!


for convenience i extracted the files to the mechtools directory.


If you are low on drive space you can safely delete all but these files.



Step 2: To Edit a Weapon

at this point you will need the console. click the widows button and search for cmd to open command prompt. Under mech_tools is a folder labeled Weapon Editor, redirect the console to this folder.


now just follow the steps listed under Manuel.txt in Weapons Editor. To speed up the processes i would recommend replacing the placeholders with the actual directories to make it a quick and simple copy/paste processes.


for now just follow the first step in the manual, Return stats for all weapons to resFile.

this is all you need for editing weapons. Simply open resFile.txt with Excel and modify the weapons stats to whatever you wish. DON'T TOUCH A WEAPON'S ID!

(quick note - weapons' heat value is actually half of what is actually generated. I don't know why, just make it half of whatever number you want it to be. Also 1 ton of ammo is calculated by slot cost times 3 divided by max ammo value)


after the file is edited and saved follow the last step of Manual.exe and Generate new stat files.

next reopen core.mw4 with MW4eXtractor.exe and click the Replace Files button. Navigate to Weapons Editor and select all the newly generated files and Compress!

Step 3: Making a New Weapon

making a new weapon is far more complex then editing a weapon. First off identify which weapon already in game most closely matches the weapon you wish to create, such traits as weapon type, projectile effects, special properties, and SFX.

For this example we will make a heavy PPC.

navigate to Mechwarrior 4 Mercenaries\Mech_tools\core.mw4\weaponsubsystems\ppcweaponsubsystem and duplicate the,{element}, and{gamemodel}. Remove the ID names as you rename them to{element}/{gamemodel}. create a new folder and place the hppc files into it, (the name doesn't matter as long as there is nothing else inside the folder)

Next open up core.mw4 with MW4eXtractor.exe and press Add Files. select the folder you put hppc into, you will be prompted with a box saying where you want this folder. Erase what's in the box and replace it with weaponsubsystems\ppcweaponsubsystem, you might notice this is the same as the directory for the other ppcs. This prompt is where in the selected files will go inside core.mw4.


once the files are added and new_core.mw4 is generated, go and open up new_core.mw4. Look under ppcweaponsubsystem for and affiliate. identify their ID number and edit your original files to include these numbers in their name. This will make them available for editing in the weapon editor! But we can't do that yet, patience.

Next step open up MW4 Table Editor 2.exe, in Mech_tools\core.mw4\tables is 1308_weaponstable.tbl and .mpt, i'm not sure if only one is needed so it's probobly best to repeat this part for both files. open the weapons table with the table editor.

scroll to the bottom of the table editor and input the location of your new Heavy PPC under file path, jsut copy what's listed in the screenshot. Put a 1 under Archive number, and 0 under mechpack if it's there. fill in the File ID with the same one you were given for it, and under name put in HPPC, or H PPC, or Heavy PPC, anything really. this is just an identifier that we will get to later. As long as it's something not already used.


Save the file and repeat for the other weapon table file.

with new_core.mw4 open with MW4eXtractor.exe and replace the table files.

Step 4: Now for Props.MW4

navigate to your extracted props.mw4\mercshellscripts\mechbay and open 17021_weapondescriptions.script, this file can be open with any text editor, I recommend Sublime text.

somewhere under //Weapons String array add weapon_names[W_HPPC] = "Heavy PPC"

under int weapons_tech[150] add weapons_tech[W_HPPC] = 2

and under string weapon_descriptions[150] add weapon_descriptions[W_PPC] = "[place your description here - remove the brackets but keep the quotations]"

Now we can edit!

Repeat Step 2, open resFile.ext and add hppc under capppc under the ppcweaponsubsystem category. input the stats you want the weapon to have then give it an id unique to itself. If the id number is used by something above it will not appear on the weapon list and if the same id number can be found below that weapon will be replaced. Make sure your id is unique!!!


Once saved Generate new stat files.

next making the weapon icon. Open props.mw4\mercshellscripts\mechbay\graphics and duplicate 14282_weapon_15.tga, remove the ID number and rename it to weapon_200 (or whatever number you gave the weapon in the resFile.txt) then go one folder lower to mercshellscripts\mechbay\graphics\installed and repeat for 14378_weapon_15.tga.

open the .tga with Photoshop or GIMP and modify them however you see fit. Dimension doesn't matter unless the weapon has ammo but i still recommend keeping at least the horizontal dimension untouched.

Step 5: Assembly

open props.mw4 with MW4eXtractor.exe and add the weapon_###.tga files (remember to isolate them and that they go in the right folders in props.mw4)

once that's done open new_props.mw4 and replace 17021_weapondescriptions.script.

with everything's said and done you should be left with _new_core.mw4 and _new_props.mw4. back up your original .mw4 files (i recommend replacing .mw4 with .bak) then remove _new_ from the new .mw4 files. (delete the extra core and props generated through the process)

boot up the game and enjoy your new weapon!

Yavin1v - - 46 comments

pretty cool :D, i will give it a try

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Guest - - 692,356 comments

So a question if I may ask. I have edited and generated new stat files but the MW4eXtractor throws up a error "Warning!! invalid filename for resfile.txt, file skipped."

I haven't changed any filenames during the process so I am at a bit of a loss as what went wrong.

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KBraid Author
KBraid - - 259 comments

you're not supposed to upload the res file to the game, you're supposed to use the res file to modify the weapons, and the resulting data files are what you upload

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archetype.2.4.7 - - 1 comments

I tried my best but I can't get this thing to work. I tried installing java re 6/7/8/9/10/11 (and even more) but commands in cmd do nothing. I can't create new stat files. Extractor seem to be working fine, but it can't edit statfiles so its useless. I only wish there where simple .exe trainer/editor that can edit weapon stats and save them directly to core.mw4 with a click of a single button.

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Cyberias - - 404 comments

You need to write the right command or use another laptop

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jlk461 - - 1 comments

Can we please get a tutorial on how to edit Mechs, I am so annoyed with the non existant torso twist range on the Koto, and want to fix it. There is plenty of room for the torso/cannon to rotate without clipping into the legs, even when moving.
Like it easily could rotate in a 100-140 degree arc, but is by default set to aproximately a 10-20 degree arc.

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