Fallout 3 Remastered (Godot)

An open-source reimplementation of Fallout 3 in Godot 4.8 (C#), in the spirit of what Oblivion Remastered did commercially and what OpenMW did for Morrowind: a modern engine that loads the game's original data files at runtime.

You must own Fallout 3. This repository contains no Bethesda assets — no meshes, textures, audio, or plugin data. Everything is read from your own installation's Data folder at runtime. Do not commit game files to this repo.

How it works

Oblivion Remastered keeps the original Gamebryo engine for game logic and uses Unreal 5 purely as a renderer. Without Bethesda's engine source that pairing isn't possible, so this project takes the OpenMW route instead: reimplement the engine in Godot and treat the original data files as the content pipeline.

Fallout 3's data lives in well-documented formats:

Format	Contents	Status
.esm / .esp	All game records: cells, worldspaces, NPCs, weapons, quests, scripts…	✅ cells, placed refs, placeable base objects, worldspaces, and terrain heightmaps decoded (EsmStore); more record types as needed
.bsa (v104)	Packed meshes, textures, sounds, voices	✅ full reader with zlib decompression (BsaArchive, GameFileSystem)
.nif (Gamebryo 20.2.0.7)	3D models	✅ static meshes: NifDocument parser + NifConverter → ArrayMesh (skinning/animation TODO)
.dds	Textures	✅ runtime load incl. normal-map green-channel flip (TextureCache)
.kf	Animations	⬜ later
.xwm / .ogg / .wav	Audio	⬜ later

Format references: fopdoc (FO3/FNV records), UESP BSA docs, and NifSkope/nif.xml (NIF block layout).

Running it

1. Open the project in Godot 4.8 (.NET edition; currently 4.8-dev7) with the .NET 10 SDK installed.
2. Build the C# solution (Godot does this on first run), then press F5.
3. The boot scene auto-detects Fallout 3 (Steam/GOG/Epic paths, or the FO3_DATA environment variable). If it can't find it, pick your Data folder in the dialog — the choice is remembered in user://fo3_data_path.txt.
4. You should see a discovery report: plugins, archives, indexed file counts, a sample NIF extraction, and a record inventory of Fallout3.esm.
5. Click Open Model Viewer to browse and render any mesh in the game's archives (orbit: LMB drag, zoom: wheel, pan: MMB/RMB drag).
6. Click Open Cell Viewer, pick an interior (try Vault101a or MegatonCommonHouse), and fly through it: hold RMB to look around, WASD to move, Q/E down/up, Shift for speed. Press Tab to drop in and walk (WASD, Space to jump, Shift to run, Esc to go back to flying). Look at a door and press E to travel to the connected cell.
7. Click Open Worldspace Viewer to fly over real Capital Wasteland terrain (hold RMB to look, WASD + Q/E, Shift for speed) — no placed objects or textures yet, just the heightmap.

Roadmap

See docs/ARCHITECTURE.md for the full plan. Short version:

1. ✅ Data discovery & container formats.
2. ✅ NIF → Godot mesh + DDS textures: render any static model from the game.
3. ✅ Cell loading: CELL/REFR records instanced with placed lights and cell ambient/fog — fly through Vault 101. 3.5. ✅ Collision & walking: Havok bhk* shapes → Jolt physics, first-person character controller — press Tab in the cell viewer to walk. 3.6. ✅ Doors & cell transitions: look at a door and press E to travel through the vault, Megaton, or any connected interiors. 3.7. ✅ Rendering overhaul: census-driven material fixes (specular, env mapping, billboards), screen-space GI, and FO3-matched interior lighting.
4. ✅ Worldspace terrain: WRLD/LAND heightmaps render real Capital Wasteland terrain (verified against Megaton's actual coordinates), with blended ground textures, placed objects/trees, and streaming. Still needed: distant LOD.
5. Gameplay systems: actors, dialogue, quests, scripting, combat, VATS — the long tail.

Legal

This is a clean-room engine reimplementation for interoperability with data files the user already owns, the same model as OpenMW, OpenXcom, or GZDoom. "Fallout" is a trademark of Bethesda Softworks/ZeniMax; this project is not affiliated with or endorsed by them.