Setting up Modding Tools

Setting up Folders

Start by creating a folder AstroneerModding in your PC. A good location is your documents folder. This folder must be on a drive with at least 10GB of free space. If you also want to make mods with Unreal Engine later you will need another 30GB.

Setting up repak

To work with .pak files, you will need to use some kind of program to extract and create them. In this guide, we will use the popular open-source program repak, developed by trumank for use with a variety of different Unreal Engine games. If curious, you can find the source code for that application here. To download a pre-built binary of this software (v0.2.2) and some useful .bat files, click HERE. (We will be using this)

Once you have downloaded the .zip extract it to your AstroneerModding folder. Then, open the new repak_for_astroneer folder. You should see the .exe and two .bat files. We will be adding the bat files to the Windows Send to window to speed up the modding workflow. This is not strictly neccessary and use the .exe like any other cli tool.

Right click both .bat files and select Create Shortcut. Then press Win+R and enter Shell:sendto. This will open a new window. Drag both shortcuts into that window. Then rename them Repack folder with repak and Unpack .pak with repak.

Extracting the Game Files

First create a new folder in your AstroneerModding folder called GameFiles. This will be where you will extract the game files to.

Next, you will need to find your Astroneer’s .pak file by going to where you have Astroneer installed.

  • The usual location for this is C:\Program Files (x86)\Steam\steamapps\common\ASTRONEER\Astro\Content\Paks.

  • If you have the Game installed anywhere outside the default Steam location you can find it on Steam by right clicking on Astroneer then going to Properties and then Local Files > Browse. From there go to the sub folder Astro\Content\Paks.

Copy the pakchunk0-WindowsNoEditor.pak files to your GameFiles folder. Finally in your GameFiles folder right click on the pakchunk0-WindowsNoEditor.pak file and select Send to > Unpack .pak with repak. This may take a minute.

Setting up UAssetGUI

UAssetGUI is tool for viewing and editing cooked .uasset files. Download the latest version from GitHub. Extract the .zip file to your AstroneerModding folder.

Opening an Asset

Go to AstroneerModding\GameFiles\WindowsNoEditor\Astro\Content\Items\ItemTypes and double click on FloodLight_IT.uasset. Since you probably have not opened one of these files before Windows will ask you for a program. Select “more apps,” then “Look for another app on this PC.” Browse to and select the UAssetGUI.exe we extracted earlier. This will set UAssetGUI as the default program for .uasset files, which you will need for making your first mod.

To make your first mod continue with Basic Modding.