Modding Tutorials/Getting Started

In this tutorial, we’re going to make a simple mod that adds a simple, useless block onto the game.

Prerequisites

First, we’ll be working with XML files, so a program like Notepad++ or Microsoft’s XML Notepad will definitely be better than just Notepad.

Making the folders

Make your mod folder (we’ll call it the mod’s root folder). This can be any name, but preferably without spaces. So we’ll call it SimpleBlock. Make sure it’s located inside RimWorld’s Mods folder. Enter the folder.

Creating the def’s XML file

Next, we’ll make the folder where we’ll put our def’s XML file. Inside this root folder, make a folder called Defs, and inside that folder, make another folder called ThingDefs. Enter ThingDefs. This is where we’ll be putting our XML file that defines our content.

Create an XML file. The easiest but slowest way is to open Notepad, press Save As..., browse to the ThingDefs folder, select All files, and then save the file as Buildings_Structure_SimpleBlock.xml. Now, open the file with your editor of choice.

Headers

All XML files we’ll be working with will need this header at the very top, so write it:

<?xml version="1.0" encoding="utf-8"?>

This basically tells the RimWorld engine’s XML reader that this file conforms to the XML 1.0 standard and that the file is encoded in UTF-8.

Building base

Since all of the buildings in this XML file will have the following properties, we’ll make an abstract ThingDef with the name BuildingBase, so your file should look like this:

<?xml version="1.0" encoding="utf-8"?>
<Buildings>

	<ThingDef Name="BuildingBase" Abstract="True">
		<category>Building</category>
		<bulletImpactSound>BulletImpactMetal</bulletImpactSound>
		<selectable>true</selectable>
		<drawerType>MapMeshAndRealTime</drawerType>
		<surfaceNeeded>Light</surfaceNeeded>
		<constructionEffect>ConstructMetal</constructionEffect>
		<repairEffect>Repair</repairEffect>
	</ThingDef>

</Buildings>

This doesn’t provide enough information to define a whole in-game building (hence the abstract) so we’ll make another object. This one will provide all of the necessary properties. We can break this one up even further, but since we’re just going to make a single object it doesn’t really matter.

Creating the simple object

Inside the Buildings tag and after BuildingBase, we’ll make a ThingDef called SimpleObject:

	<ThingDef ParentName="BuildingBase">
		<eType>BuildingComplex</eType>
		<thingClass>Building</thingClass>
		<altitudeLayer>BuildingTall</altitudeLayer>
		<passability>Impassable</passability>
		<castEdgeShadows>true</castEdgeShadows>
		<fillPercent>1</fillPercent>
		<placingDraggableDimensions>0</placingDraggableDimensions>
		<tickerType>Never</tickerType>
		<rotatable>true</rotatable>
		<neverMultiSelect>true</neverMultiSelect>
		<holdsRoof>false</holdsRoof>
		<Overdraw>false</Overdraw>
		<designationCategory>Building</designationCategory>
		<staticSunShadowHeight>0.5</staticSunShadowHeight>
		<blockLight>true</blockLight>
		
		<defName>SimpleBlock</defName>
		<label>Simple block</label>
		<description>An ugly thing.</description>
		<texturePath>Things/Building/SimpleBlock_Atlas</texturePath>
		<menuIconPath>Things/Building/SimpleBlock_MenuIcon</menuIconPath>
		<maxHealth>50</maxHealth>
		<flammability>0.1</flammability>
		<workToBuild>100</workToBuild>
		<mineable>false</mineable>
		<size>(1,1)</size>
		<costList>
			<li>
				<thingDef>Metal</thingDef>
				<count>7</count>
			</li>
		</costList>
		<filthLeavings>
			<li>
				<thingDef>SlagRubble</thingDef>
				<count>2</count>
			</li>
		</filthLeavings>
		<designationHotKey>Z</designationHotKey>
	</ThingDef>

Hopefully, you’ll be able to understand what each property is once you read the page on ThingDef.

Okay, we’re done with our simple block! Onto the next part!

Creating resources

To make our block actually visible, we need to add resources. In our mod’s root folder, make a new folder called Textures. Inside of that, make another called Building. Enter it.

Make two PNG images: your actual block called SimpleBlock_Atlas which will be 64x64, then another called SimpleBlock_MenuIcon which will also be 64x64.

Finishing touches

We need to identify our mod so that RimWorld can recognize it. Browse back to the mod’s root folder and create a new folder called About. Inside of it, create a new XML called About.xml. It should look like this:

<?xml version="1.0" encoding="utf-8"?>
<ModMetaData>
  <name>Simple Block</name>
  <author>Your name here!</author>
  <url>about:blank</url>
  <targetVersion>Alpha 3</targetVersion>
  <description>A very simple block for a tutorial.</description>
</ModMetaData>

If you’d like, you can also add an image called Preview. You can make that image any size.

Testing

Let’s test our new mod! Fire up RimWorld, making sure to turn on Development mode in the options menu. Turn on the mod, and press the tilde key (~) to check for any errors thrown on runtime. That’s right, no errors! Enjoy your first mod!

Download

From now on, we'll be using GitHub to store finished tutorials. Each branch in the Git repository will contain an up-to-date browsable and downloadable archive for a specific tutorial. In future and more complex tutorials, there might be individual commits for each step in the tutorial.

You can take a look at the branch for this tutorial here, and you can download a zip archive here.

Conclusion

You now know how to:

• make a simple, single-file mod
• manage XML files along with their resources
• create a building that covers a single space
• finalize a mod for consumption
• learn how to follow instructions

Next, we’ll learn how to make various types of items.