How To Use Mod:Switch

By SubRosa

What Is Mod:Switch?

Friendly modders always use mod:switch for their conversion mods. It is probably overkill for minor mods that change only a one or two files, but for major mods that drastically alter the game it is the only way to go.

Note that you must have RTW version 1.2 or higher to use mod switch.

So what is mod:switch? It is a command line switch that tells the game to look in an extra folder for files to use. It uses whatever it finds there in preference to what exists in the main game folders. This allows the modder to replace original game files with modded ones, without actually removing the originals. So a person can play a mod and the original game with the same installation of Rome Total War.

Neat huh?

Creating A Mod Using Mod:Switch

To use mod:switch simply create a folder inside your root RTW folder (the same folder that RomeTW.exe is located in) with the name of your mod. Place all your modded files and folders in there as if that were the root folder of the mod, using the same hierarchy that RTW uses. The Barbarian Invasion and Alexander expansions are two examples of mod:switch being used.

Here is an example using the mod folder of Amazon:

Rome Total War
|   |-Data
|   |-Preferences
|   |-Saves
|   etc...

When building your mod, place all the files you change into the appropriate folders under the mod folder. Note that the Preferences and Saves folders are generated automatically by the game, so you do not have to create them within your mod folder, or provide them to others when you distribute your mod.

Things To Look Out For

There are a few tricky things to be aware of when using mod:switch.

First, for the game to run you must copy the contents of the several folders from vanilla RTW into your mod switch folder, even if you do not modify them at all. You do not need every single file, but it is easiest to play it safe and just copy everything. Otherwise when you try to start a new game and select Imperial Campaign, it will fail and go back to the main screen.

  • Data\World\Maps\Base
  • Data\World\Maps\Campaign\Imperial_Campaign
You will also need several of the files in Data\Text folder:
  • campaign_descriptions.txt
  • expanded.txt
  • expanded_bi.txt
  • export_units.txt
  • shared.txt
  • strat.txt

Second, for the game to see some of the files in your mod folder you will often have to specifically tell it to look there. The most notable examples of this are the models and textures that are referenced in Data\Descr_Model_Battle.txt, Descr_Model_Strat.txt, descr_sm_factions.txt, descr_sm_resources.txt, descr_standards.txt, and Descr_Banner.txt. You must add in the name of your mod folder to the path given for the files they refer to. Like so:

type east_cavalry
skeleton fs_hc_javelinman, fs_hc_swordsman
indiv_range 40
texture pontus, amazon/data/models_unit/textures/unit_eastern_peltast_pontus.tga
model_flexi amazon/data/models_unit/unit_eastern_peltast_high.cas, 15
model_flexi amazon/data/models_unit/unit_eastern_peltast_med.cas, 30
model_flexi amazon/data/models_unit/unit_eastern_peltast_low.cas, 40
model_flexi amazon/data/models_unit/unit_eastern_peltast_lowest.cas, max
model_sprite pontus, 60.0, amazon/data/sprites/pontus_east_cavalry_sprite.spr
model_tri 400, 0.5f, 0.5f, 0.5f

If your modded material is not showing up in the game, this is one of the first culprits to look for.

Starting The Modded Game

To start the game using the mod folder you have to edit the command line of the game. See the article on command line switches for full details on editing the command line. You must add the command line switch "-mod:[mod folder name]. For example to use the folder above you would change it to:

"C:\Program Files\Rome - Total War\RomeTW.exe" -mod:amazon

Mod:Switching Barbarian Invasion or Alexander

You can use mod:switch with BI or Alexander, however you have to do a few things differently. First you must place your mod folder within your root BI folder (or Alex), not the root RTW folder. Then you must use slightly different command line switch: -mod:bi/[mod folder name]. For example:

"C:\Program Files\Rome - Total War\RomeTW.exe" -mod:bi/amazon

It appears you must also copy the entire contents of the original BI (or Alexander) folder into your mod folder as well. It is possible some files may not be needed, but since I am not sure which ones can be discarded safely I recommend keeping them all.