Garry's Mod Wiki

Gamemode Creation

Gamemode Content

Gamemode content such as maps, models and sounds should be placed in gamemodes/content/ folder. (i.e. gamemodes/content/models/..).

Gamemode Folder

To create a new gamemode you need to create a new folder in the gamemodes folder. The folder should take the name of your gamemode. Inside of that folder there should be a text file named whatever your folder is.

For instance, if my gamemode was called SuperKillers, I would create a folder in garrysmod/gamemodes/ called superkillers. Then inside that folder I would create a text file called superkillers.txt.

Note that in previous versions of Garry's Mod this file was always called info.txt - but was changed in Version 13 to reflect the changes to the content.

Gamemode Text File

The .txt file you created needs to be a keyvalues file.

"superkillers" { "base" "base" "title" "Super Killers" "maps" "^sk_" "category" "other" "menusystem" "1" "workshopid" "15895" "settings" { 1 { "name" "sk_maxfrags" "text" "Max Frags" "help" "The maxiumum number of frags before a map change" "type" "Numeric" "default" "20" } 2 { "name" "sk_grenades" "text" "Allow Grenades" "help" "If enabled then grenades are enabled" "type" "CheckBox" "default" "1" } } }
key description
title The 'nice' title of your gamemode. Can contain spaces and capitals.
maps The map filter for your gamemode. This is used to correctly categorise maps in the map selector. This should only be set if the maps are unique to your gamemode.
category The category your gamemode falls into. See below for details.
menusystem Include and set to 1 if this gamemode should be selectable from the main menu
workshopid Optional. If your gamemode is on Workshop then this should be the workshopid of the file. (You won't have a workshopid until you upload - so you will need to set this in an update)
settings See below for details


Your gamemode can have only one category, out of the following choices:

  • rp - Roleplay - Your gamemode contains Roleplay elements. If your gamemode has "RP" in its name, this is the category for you.
  • pvp - Your gamemode is based mostly on Player versus Player combat, be that competition or just a shooter gamemode.
  • pve - Your gamemode is based more around Player versus Environment combat, such as survival or campaign gamemodes. This does not exclude PvP.
  • other - Your gamemode does not fit in any of the above categories, for example sandbox or hangout type gamemodes.


The settings table allows you to create server configuration convars for your gamemode. It's completely optional. Your text file doesn't have to have a settings section.

In previous versions of GMod this section used to have its own file, in gamemode/<gamemode>/content/settings/server_settings/. It was moved to the root folder to decrease load times.

These settings are configurable in the main menu in GMod. Each entry has a number of fields.

key description
text The text to show in game to describe this convar
help The help text to show on the convar (in the console)
type Either Text, CheckBox or Numeric. These are case-sensitive!
default The default value for the convar
singleplayer Whether this convar should show up for singleplayer, just having this key will enable it, it doesn't matter what the value is

Menu Background Images

If you want to include backgrounds with your gamemode place them in gamemodes/<yourgamemode>/backgrounds/. They must all be jpg images.

Menu Logo Image

To supply a menu logo image place a .png file in gamemodes/<yourgamemode>/logo.png. This image should be 128 pixels high and up to 1024 pixels wide. The default logo is 288 x 128.

Menu Icon

To supply a menu icon place a .png file in gamemodes/<yourgamemode>/icon24.png. This image should ideally be 24x24 pixels but it can be up to 32x32. The server list displays the icons at 24x24 while the gamemode selection uses 32x32. Here's where it will appear.

Init and Shared Files

Three files are needed for your gamemode to function properly. These go into your <gamemode>/gamemode/ folder.

Please note, that while we use shared.lua in the example below, it is completely optional. init.lua and cl_init.lua are not!


This file is called when the server loads the gamemode. The example below tells the resource system to send the two files to the client, and then loads shared.lua.

AddCSLuaFile( "cl_init.lua" ) AddCSLuaFile( "shared.lua" ) include( "shared.lua" )


This file sets some common variables and creates the Initialize function. This is the only function you NEED to define. All others will be called from the base gamemode.

GM.Name = "Super Killers" GM.Author = "N/A" GM.Email = "N/A" GM.Website = "N/A" function GM:Initialize() -- Do stuff end


This file is called when the client loads the gamemode. You would put client specific things in here. We load shared.lua. Note that you can only 'include' files here that have been 'AddCSLuaFile'd on the server.

include( "shared.lua" )


This is a variable that will return the current folder name of the gamemode being run.

For example, If you are playing the gamemode Trouble In Terrorist Town this variable will equal to terrortown

Deriving Gamemodes

If you are deriving your gamemode from something other than base, use this function to tell the engine that we do.

You must call the function on both, client and server, and since our shared.lua is included from both, cl_init.lua and init.lua, we can do it once, in shared.lua.

In the example below, let's say we derive our gamemode from sandbox, so we add this to our shared.lua, somewhere above all function definitions is a good place:

DeriveGamemode( "sandbox" )

Modding Gamemodes

If you wish to edit a gamemode but you do not want it to appear under a different category in the server browser and you do not want the edited version to override the original, in cases like editing Trouble In Terrorist Town where a game update could undo your edits, you can copy the gamemode as usual and append _modded to the gamemode's folder name (for example terrortown_modded), as well as the .txt file inside the gamemode folder.

You will still load it as terrortown_modded on your server, but it will appear as terrortown to the rest of the world.

Common Errors

Error loading gamemode: info.Valid

Your Gamemode Text File is invalid or was not found.

Error loading gamemode: !IsValidGamemode

The game could not find cl_init.lua or init.lua of your gamemode. Make sure these files exist in the correct place:

  • gamemodes/**yourgamemodename**/gamemode/init.lua
  • gamemodes/**yourgamemodename**/gamemode/cl_init.lua

Game crashes/freezes on death

You have not assigned a playermodel to the player.