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Outer Wilds New Horizons

This is the official documentation for New Horizons, a framework for creating custom planets in the game Outer Wilds by Mobius Digital. Planets are created using simple JSON and XML files and are loaded at runtime. An API is also provided for more advanced use-cases.

Getting Started

Before starting, go into your in-game mod settings for New Horizons and switch Debug mode on. This allows you to:

  • Use the Prop Placer tool. This convienence tool allows you to place details in game and save your work to your config files.
  • Print the position of what you are looking at to the logs by pressing "P". This is useful for determining locations to place props the Prop Placer is unable to, such as signal scope points or dialogue triggers.
  • Use the "Reload Configs" button in the pause menu. This will restart the current solar system and update all the planets. Much faster than quitting and relaunching the game.

Get VSCode

Please get VSCode or some other advanced text editor, as it will help highlight common errors.

Planets are created using a JSON file format structure, and placed in a folder called planets (or in any subdirectory of it) in the location where New Horizons is installed (by default this folder doesn't exist, you have to create it within the xen.NewHorizons directory). You can learn how the configs work by picking apart the Real Solar System mod or the New Horizons Examples mod.

To locate this directory, click the "⋮" symbol next to "New Horizons" in the Outer Wilds Mod Manager and then click " show in explorer" in the pop-up.

Click the three dots in the mod manager

Create a new folder named

Planets can also be placed in a folder called planets within a separate mod, if you plan on releasing your planets on the mod database. The Config Template is available if you want to release your own planet mod using configs.

Now that you have created your planets folder, this is where you will put your planet config files. A config file will look something like this:

  "name": "Wetrock",
  "$schema": "",
  "starSystem": "SolarSystem",
  "Base": {
    "groundSize": 100,
    "surfaceSize": 101,
    "surfaceGravity": 12,
    "hasMapMarker": true
  "Orbit": {
    "semiMajorAxis": 1300,
    "inclination": 0,
    "primaryBody": "TIMBER_HEARTH",
    "isMoon": true,
    "isTidallyLocked": true,
    "longitudeOfAscendingNode": 0,
    "eccentricity": 0,
    "argumentOfPeriapsis": 0
  "Atmosphere": {
    "size": 150,
    "fogTint": {
      "r": 200,
      "g": 255,
      "b": 255,
      "a": 255
    "fogSize": 150,
    "fogDensity": 0.2,
    "hasRain": true
  "Props": {
    "scatter": [
        "path": "DreamWorld_Body/Sector_DreamWorld/Sector_DreamZone_1/Props_DreamZone_1/OtherComponentsGroup/Trees_Z1/DreamHouseIsland/Tree_DW_M_Var",
        "count": 12

The first field you should have in any config file is the name. This should be unique in the solar system. If it isn't, the mod will instead try to modify the planet that already has that name.

After name is starSystem. You can use this to place the planet in a different system accessible using a black-hole or via the ship's warp drive (accessible from the ship log computer). To ensure compatibility with other mods this name should be unique. After setting a value for this, the changes in the config will only affect that body in that star system. By default, it is "SolarSystem", which is the scene from the stock game.

Including the "$schema" line is optional, but will allow your text editor to highlight errors and auto-suggest words in your config. I recommend using VSCode as a text editor, but anything that supports Json files will work. Something as basic as notepad will work but will not highlight any of your errors.

The config file is then split into modules, each one with its own fields that define how that part of the planet will be generated. In the example above I've used the Base, Orbit, Atmosphere, and Props modules. A config file must have a Base and Orbit module, the rest are optional.

Each { must match up with a closing } to denote its section. If you don't know how JSONs work then check Wikipedia.

Modules look like this:

  "Star": {
    "size": 3000,
    "tint": {
      "r": 201,
      "g": 87,
      "b": 55,
      "a": 255

In this example the Star module has a size field and a tint field. Since the colour is a complex object it needs another set of { and } around it, and then it has its own fields inside it : r, g, b, and a. Don't forget to put commas after each field.

Most fields are either true/false, a decimal number, and integer number, or a string (word with quotation marks around it).

To see all the different things you can put into a config file check out the Celestial Body schema.

Check out the rest of the site for how to format star system, dialogue, ship log, and translation files!

Publishing Your Mod

Once your mod is complete, you can use the planet creation template GitHub template.

Helpful Resources

The texturemap/heightmap feature was inspired by the Kerbal Space Program mod Kopernicus. A lot of the same techniques that apply to planet creation there apply to New Horizons. If you need help with planetary texturing, check out The KSP texturing guide.

Photopea is a free browser-based photo editor which has useful features like rectangular-to-polar coordinate transformation, useful for fixing abnormalities at the poles of your planets.

Helpful Mods

These mods are useful when developing your addon

  • Unity Explorer - Used to find the paths of game objects for copying and can be used to manually position props, ship log entries, and more.
  • Collider Visualizer - Useful when creating dialogue triggers or reveal volumes
  • Save Editor - Useful when creating a custom ship log, can be used to reveal all custom facts so you can see them in the ship's computer

Helpful Tools

These tools/references are highly recommended


This work is unofficial fan content created under permission from the Mobius Digital Fan Content Policy. It includes materials which are the property of Mobius Digital, and it is neither approved nor endorsed by Mobius Digital.

We are not responsible for any mods created using the New Horizons modding framework and assume no responsibility in the event an addon violates the terms.


The license for this project is available on the GitHub repository.