Modding

Mods (short for modification) are small packages that add to or otherwise affect gameplay in RimWorld. They include art packs (for reskinning the game), more weapons, more incidents, furniture, and game-balancing mods.

This page is about making mods. For info about using mods, see Installing mods.

Mod-making tutorials

Mod-making tutorials are available at the Modding Tutorials page.

Contributions are appreciated and will help new modders like you.

Mod structure

Format of files

For defining new game content, XML files are used. Here is an example of the format, that applies to most of the definitions:

<?xml version="1.0" encoding="utf-8" ?>
<SomeDefs>
   <SomeDef>
      <defName>MyNewDefinitionOfContent</defName>
      <!-- more tags will appear depending on what are you defining -->
   </SomeDef>
</SomeDefs>

Remember, that the word Some must be replaced by the name of whatever are you defining. For thing it's <ThingDef>.

The RimWorld mods use the following directory structure:

┌About 
├╴About.xml (Contains info about the mod)
├╴Preview.png (Image that appears above the mod info in game. Max width 600px.)
│
├Assemblies (If your mod uses any DLL files put them here)
├╴MyMod.dll
│
├Defs (Contains xml definitions of the mod)
├┬ThingDefs
│├╴Things.xml
│└╴Buildings.xml
├┬ResearchProjectDefs
│└╴MyProjects.xml
│the folder name must be specific here. Look in Core mod to see what are other names supposed to be
│
├Sounds
│
├Source
├╴MyMod.cs (Optionally, put the source code of your mod here)
│
├Strings
│
├Textures (Put any image textures here, preferably in .png format.)
└┬Things
 ├╴MyMod_ImageA.png
 └╴MyMod_ImageB.png

Mod info

This is found in MODNAME/About

The contents of About.xml are plain text. HTML Markup tags cause NullRef's.
You can have an image for your mod. Restrict the image width to 600 pixels

Textures

These are found in MODNAME/Textures

You can have any path you want from this point on.
When referencing textures in your mod, using <TexturePath>, have the complete path relative to your mod, including the filename (but not the file extension). Example for the RoyalBed Testmod: <TexturePath>Things/Building/RoyalBed</TexturePath>
You can randomize textures within a folder using a <textureFolderPath> pointing at a folder with multiple textures inside. Each Thing of the given def will have a random texture from the folder.

Interactive "things"

A thing is anything that exists in the game world. It includes resources, races (humanoid and animal), buildings, furniture, and many others.

These are defined in MODNAME/Defs/ThingDefs If you make a new workbench, you'll need to define a recipe for it. This is a list, so you can have many new recipes listed.

The recipes themselves are defined in: MODNAME/Defs/RecipeDefs In here you can define what ingredients/resources are required, what can be used, and what the default recipe is.

Any new resources will need to be defined in: MODNAME/Defs/ThingDefs

Turrets

These are defined in two files in: MODNAME/Defs/ThingDefs Buildings_Big.xml and Weapons_Guns.xml (Remember, these can be named anything)

Buildings_Big.xml defines the structure of the turret itself. For example:

<building>
	<turretGunDef>Gun_TurretImprovised</turretGunDef>
	<burstCooldownTicks>300</burstCooldownTicks>
</building>

Weapons_Gun.xml defines the weapon the turret uses. Anything can be used as a weapon for turrets, including grenades.

Resources

These are defined in: MODNAME/Defs/ThingDefs/Resources.xml

Research projects

These are found in: MODNAME/Defs/ResearchProjectDefs

You can have research trees as well, where additional research projects get unlocked as you move through. This is how to add prerequisites:

<prerequisites>
	<li>-this is the <defName> of the prerequisite-</li>
</prerequisites>

Because it's a list, you can have multiple prerequisites for a research project.

Advice

The tilde key (` or ~) brings up the development console, which will report any errors or warnings it encounters when a mod loads or during gameplay. This is the quickest way to see what, if any, errors exist in your mod. (You don't need to turn on development mode for this.)
Use development mode (found in the options menu) to help debug your mod, spawn items related to your mod, or fire incidents at will. (Or just mess around, if you'd like.)

References