OWCraft

OWCraft: Minecraft inside Outer Wilds

Fly your ship to a planet, get out, press F6, and you're playing real Minecraft there. Break and place blocks, open your inventory, light TNT, and build a house on Timber Hearth. Press F6 again to get back into your spacesuit. The house stays on the planet.

This is a passthrough mod, built on chasmlol's SkyCraft (Minecraft in Skyrim). Both games run at the same time and talk over shared memory:

• Minecraft simulates the player and the blocks against the planet's real surface.
• Outer Wilds draws the blocks on the planet with its own lighting, plus Minecraft's hand, HUD and

  screens on top.

See docs/DESIGN.md for how it works.

Status: experimental, but playable. It has been tested on one Windows PC: building, TNT and walking around planets work at 60 fps. Expect rough edges (see Known limitations).

Install (players)

You need Windows, Outer Wilds (Steam) and Minecraft Java Edition.

1. Outer Wilds: install the Outer Wilds Mod Manager and

   start Outer Wilds from it once.

2. OWCraft: download Yaekai.OWCraft-.zip from

   Releases. Unzip it into %AppData%\OuterWildsModManager\OWML\Mods\, so you get a Mods\Yaekai.OWCraft folder.

3. Minecraft: install Fabric Loader 0.19.5 or newer for

   Minecraft 26.3. Put two files in your .minecraft\mods folder:

   • skycraft-+owcraft..jar from Releases;
   • Fabric API for 26.3.
4. Start Minecraft with the Fabric profile in the normal launcher.
5. Start Outer Wilds from the Mod Manager.

Play

1. Once Outer Wilds connects, Minecraft opens its own void world (or creates it the first time). The

   planet supplies the ground.

2. In Outer Wilds, land somewhere, stand on the ground and press F6.
3. Minecraft controls apply:
   • O opens Minecraft's menu;
   • F5 switches to third person (Minecraft's body is drawn on the planet), like in Minecraft;
   • Esc pauses Outer Wilds, or closes a Minecraft screen;
   • F6 leaves Minecraft mode.

Each patch of planet maps to its own fixed area of the Minecraft world, so whatever you build is saved by Minecraft. It is still there after time loops and restarts.

Settings (Mod Manager):

Build from source

You need the .NET SDK and a JDK 25.

Outer Wilds side:

dotnet build host/OWCraft.csproj -c Release

If Outer Wilds isn't in the default Steam folder, add -p:GameDir="D:\Games\Outer Wilds". When the Mod Manager is installed, the build copies OWCraft.dll, manifest.json and default-config.json into %AppData%\OuterWildsModManager\OWML\Mods\Yaekai.OWCraft.

Minecraft side: SkyCraft's Fabric mod plus guest/skycraft-owcraft.patch. The patch:

• skips presenting Minecraft's own hidden window while linked (this took Minecraft from 25 to 60 fps);
• reads the overlay back at once, so inventory screens keep up with the mouse;
• sets OWCraft's defaults: the Local\OWCraft_v1 link, no "Skyrim destruction" (Outer Wilds can't

  carve its planets), Minecraft keeps running when Outer Wilds closes, and no Discord status;

• keeps speed and elytra flight when Outer Wilds moves you to a new planet tile, and brings the

  mobs and items around you along;

• lets mobs path over the planet surface, and holds mobs and items still where the planet's ground

  hasn't streamed in yet (instead of letting them fall into the void);

• sends arrows, tridents and dropped items through the scene so Outer Wilds draws them;
• adds a frame-time log.

git clone https://github.com/chasmlol/SkyCraft.git
cd SkyCraft
git checkout bfcaf178524b92c2cdeb88e4ce0f13ef9ded6f32
git apply path/to/OWCraft/guest/skycraft-owcraft.patch
cd fabric
./gradlew build       # the jar lands in build/libs
./gradlew runClient   # or run it straight from source

Known limitations

• Translucent blocks (glass, water, ice) are drawn opaque.
• Outer Wilds' own player doesn't collide with placed blocks yet. Only the Minecraft player does.
• The Minecraft world doesn't follow Outer Wilds' day/night.
• Nether portals and other dimensions aren't supported.
• Mobs only find the planet's ground within about 40 blocks of you. Further away they wait in place.

Repository layout

• host/: the OWML mod (C#). Link/ holds the shared-memory protocol, World/ the planet tiles,

  collision and rendering, Player/ the movement, input and commands, UI/ the overlay.

• guest/: the patch to SkyCraft's Fabric mod.
• tests/VoxelTest: a unit test for the collision voxelizer.
• tools/check-logs.py: reads both games' logs after a play test and lists known problems.
• docs/DESIGN.md: the architecture.
• CHANGELOG.md: what changed in each release.
• MODLOG.md: the full development log, test by test.

Honesty note

This mod was written by an AI (Claude, by Anthropic), directed and play-tested by Yaekai. It ports SkyCraft's Skyrim-side design to Outer Wilds. MODLOG.md records what was done and verified, and THIRD-PARTY-NOTICES.md what was ported.

No game files, decompiled code or Minecraft assets are in this repository. Textures come from your own Minecraft at runtime.

License

MIT (LICENSE). Parts ported from SkyCraft are MIT too; see THIRD-PARTY-NOTICES.md.