MOD INSTALLATION TUTORIAL
for
MEDAL OF HONOR: ALLIED ASSAULT
by Crow King
crowking@autokick.com
What is a Mod?
When id software first began creating games, they designed them in such a way as to allow users to customize their content. This started with skins and quickly grew to include almost all elements of the game. MOHAA is based on a variant of id’s Quake3: Team Arena engine and uses an architecture that gives modders quite a bit of opportunity to be creative.
"These creations are called ‘mods’, short for modifications. They can range from simple skins to entirely new games. In MOHAA, mods come in the form of pk3 files (called pack files) and generally fall into a few categories:
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Skins
A skin mod adds or changes uniforms in the game. It can also be used to change the ‘skin’ on just about anything, from chairs to weapons. However, skins cannot change the shapes of objects, so you couldn’t add an M1 Carbine to the game just be re-skinning the Thompson.
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Maps
With the release of the SDK (software development kit) for MOHAA, modders can now create new maps for the game These can be single or multi- player.
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Blood
Blood mods cause your bullets to create ‘puffs’ on enemies, splatter marks on walls, etc.
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Sounds
Sound mods replace the game’s original sounds. Most focus on weapons.
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Weapons
Weapon mods generally focus on creating realistic damage in the game, though some focus on the more fanciful.
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Gameplay
Gameplay mods affect different elements on how they game is played, such as gravity, jumping or running speed.
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Exotic
These mods focus on creating a theme within the game, such as the adult oriented "Ultimate BaHchelor pad".
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Total Conversion
Combining all of these different types of mods can result in an entirely new game.
How Do Mods Work?
MOHAA modders create their mods by creating new pk3 files for the game. To understand how this works, you have to understand a little about how Quake functions. When you first start the game, it loads information from two sources: binaries and pack files.
A binary is an executable (.exe) or dynamic link library (.dll). Its contents can’t be changed (at least not easily) and so modding for MOHAA doesn’t happen at this level. The binaries for the game contain information about how to draw graphics on the screen, how to communicate over the network and what the game world’s physics are like. They are often called the game engine.
The pack files contain all of the information about the world. What the objects are, how they look and sound, how they move and other types of content. They also include all of the maps. The pack files are often called the game content.
While modders can’t change the binaries, they can change many of the elements of the pack files. This is because a pak file is nothing more than a zipped archive that has had its extension changed from .zip to .pk3. So, to look inside a pack file, all you need is WinZip. You can extract its contents, change them, and then re-zip them into a new file. Oila, you’ve got a mod.
Well, its not that easy. The magic comes in the form of figuring out what all those things are inside the pack files and how to change them. But that is outside the scope of this document.
Installing a Mod
When you download your mod, it will probably be in zip format. Most modders distribute their mods in the form of a zip file because they need to include directions for how to use the mod and they don’t want to put this into the pk3 file itself.
The first thing you should do is unzip the zip file and look for the author’s directions. They will probably be in a text file called “readme.txt” or some other easily identifiable file. Read the directions carefully. The installation instructions in this document may need to be changed slightly for specific mods. If in doubt, e-mail the author or ask for help in a website forum.
Once you have your mod unzipped (or if it was already in a pk3 format when you downloaded it), you need to decide where to put it. This depends on the type of mod it is. If it is a server side mod, then you only need to install it on the server for it to work. Players do not need to have it installed. A good example of a server sided mod is a realism mod.
On the other hand, if it is a client side mod, then it must be on the server as well as on all players’ machines. If a player does not have it installed and connects to the server, the result is unpredictable. In the case of a map, the server will simply disconnect the player when the map loads. But in the case of a new weapon mod, the player’s machine may crash. If you have a client side mod installed on your server, you should let players know by including the mod in your server’s name.
To install the mod on the server, follow the author’s directions. If there are no directions, install it by bringing the server down and copying the mod’s pk3 file into your server’s MOHAA\main directory. While you may be able to copy the pk3 file to the server without taking the server down, it will not go into effect until the server is restarted.
If the mod is not a pk3 file and the author did not include directions, you should contact the author or ask for assistance in the forums of the website where you downloaded the mod. If the mod was a zip file and contains a directory structure (but no pk3 file), you may be able to install it by unzipping it into your MOHAA\main folder on the server, but you should make certain that it does not overwrite any existing files. Some mods (such as the Message of the Day mod) require this type of installation.
To remove a mod, just bring the server down and take the pk3 file out of your MOHAA\main directory. Mods do not overwrite the game’s original pack files, so just taking it out of the game path will disable them.
Troubleshooting Mods
If you’re having trouble on your server and you suspect a mod, or if you install a mod and it doesn’t seem to work, you may be experiencing a collision. Collisions occur when two (or more) mods that change the same thing in the game are installed on the same server. The results can be very unpredictable.
For example, if you installed two different realism mods on your server, one of three things could happen. The first mod would work in its entirety, and the second would be ignored. Or, the opposite could occur, where the first mod is ignored and the second works. But what is most likely to happen is that some parts of the first mod will work, some parts of the second will work and parts of each will be broken.
To troubleshoot this, you should remove all mods from your server’s MOHAA\main directory. Then, add one mod back at a time and run the server. If everything is ok, continue this process until you find the culprit that is causing the collision.
Another common problem is caused by the server running while you are uninstalling a mod or trying to overwrite an existing mod. When the server runs, it locks the pack files. To delete or overwrite a pack file installed on the server, you will need to first bring the server down.
Good luck! Blade
