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Image reference (original game): Fallout: New Vegas · original-game artwork, provided by IGDB. Image rights remain with their respective owners. This illustrates the referenced original game, not the actual visuals of this rewrite or mod.

Source maintainer: slaterain · Revision: fb4b846471f7 · Catalogued: 2026-10-12

Source license: MIT · LICENSE-APACHE · LICENSE-MIT · Article: Source README (format adapted)

The source README follows, with formatting adapted for this site and images replaced by source links. Feature, completion and testing claims belong to its authors and have not been independently playtested here. The Traditional Chinese translation was prepared with AI assistance.

nv-rs

[README image：Rust](https://www.rust-lang.org/)
[README image：Engine](https://bevyengine.org/)
[README image：License: MIT](https://github.com/slaterain/nv-rs/blob/fb4b846471f7fb61aa770a900a967cbb524b79c1/LICENSE-MIT)
[README image：License: Apache 2.0](https://github.com/slaterain/nv-rs/blob/fb4b846471f7fb61aa770a900a967cbb524b79c1/LICENSE-APACHE)
[README image：Platform](https://github.com/slaterain/nv-rs/blob/fb4b846471f7fb61aa770a900a967cbb524b79c1/docs/PLAYTESTING.md)
[README image：Status](https://github.com/slaterain/nv-rs/blob/fb4b846471f7fb61aa770a900a967cbb524b79c1/docs/MILESTONES.md)

A from-scratch reimplementation of Fallout: New Vegas in Rust with the
Bevy engine. It runs the game from the Data folder of an installation you
own and aims to behave exactly like the original (1:1).

[!IMPORTANT]
nv-rs is an independent project, not affiliated with or endorsed by
Bethesda Softworks, ZeniMax Media, Obsidian Entertainment or Microsoft. It
contains no game files; you need your own legally obtained copy of the game.
See LEGAL.md.

How it works

  • Original files at runtime. nv-rs reads the game’s own plugins, archives,
    meshes, textures, sounds, menus and shaders directly. There is no
    conversion step, and the installation is never modified.
  • Behaviour from the original program. Rules, constants and formulas come
    from the game’s program (FalloutNV.exe, read in Ghidra), its data, and
    recordings of the original game. Nothing is invented or tuned by eye. The
    method is described in docs/METHODOLOGY.md and the
    decisions behind it in docs/adr/.
  • Ported system by system. Every function in FalloutNV.exe is mapped
    and tracked in a ledger (docs/LEDGER.md). The game’s code
    is being translated into Rust function by function in the engine crate,
    each piece marked with the address it came from and tested, in the order
    that matters most for running the game. The plan is in
    docs/ENGINE_PORT_PLAN.md.
  • Checked against the original. Tools in research/ record
    what the original program actually does (function results on the real CPU,
    live arguments and state) so that Rust code can be tested against it.
  • Simulation separate from presentation. Game rules live in plain Rust
    crates with no external libraries. The Bevy app only draws, plays sound
    and reads input. That split also keeps the planned VR support possible
    (docs/VR.md).

Repository layout

nv-rs/
├── Cargo.toml         # core workspace (no external crates)
├── crates/            # readers, game rules, tools and test fixtures (table below)
├── viewer/            # the Bevy app (its own workspace, Bevy 0.16)
├── research/          # Ghidra scripts, the engine map and native oracle tools
│   ├── ghidra/        # identity, complete export, function cards, name import
│   ├── engine-map/    # every function of the exe, by unit and subsystem
│   └── nv-oracle/     # nv-call, nv-probe, nv-inject (own workspace, 32-bit Windows)
├── docs/              # roadmap, method, decisions, ledger, topic findings
├── scripts/           # acceptance routes, the ledger, packaging
└── distribution/      # files shipped in playtest packages
Group Crates What they do
Formats esm, bsa, nif, dds, mp3, bink, speedtree, shaders, assets, fos Read the game’s files: plugins and records, archives, meshes and animations, textures, audio, movies, trees, compiled shaders, the loose-file/archive lookup, and the original game’s saves (read-only).
Engine port engine FalloutNV.exe translated function by function, running on a model of the game’s memory (ADR-0006, docs/ENGINE_CRATE.md).
Game world, physics, script, scriptgen, ui, preview, cellview The game’s rules: world state and the per-frame order, actors, AI, combat, dialogue, quests, inventory, saves, collision, the script engine and the game’s scripts translated to Rust, menus built from the game’s XML, and per-cell scene data.
Tools nvinspect Command-line inspection of real game data: records, cells, meshes, collision walks, coverage tables and more.
Test content testdata Builds synthetic plugins, archives and meshes for tests, so tests never need game files.
App viewer (binary nv-viewer) The Bevy app: rendering, audio and input on top of the game crates.

Roadmap

Engine port

The main work right now. Progress is measured in the ledger
(docs/LEDGER.md).

  • [x] Phase 0: the map and the ledger. Every function in the exe has a
    unit, a subsystem and a status.
  • [ ] Translation (ongoing): over 10,000 of the exe’s functions are
    translated so far (about 15% of the whole program; counting only game
    code, about 35% is translated or traced). Most are not yet switched on
    in play.
  • [ ] Phase 1: the frame skeleton (nearly done): the game’s per-frame
    order, from the main loop down, drives the order of the app’s systems
    (docs/FRAME_SKELETON.md).
  • [ ] Phase 2: the state model and saves: the game’s state lives in the
    translated code’s memory, checked by reading a real save and writing it
    back identically.
  • [ ] Phase 3 onward: whole systems switched over one at a time: the
    script engine, conditions, AI, animation, menus, the rest of Havok and
    audio.

Milestones

Each milestone has an acceptance gate checked against the original game.
Status and evidence are in docs/MILESTONES.md.

  • [ ] M1: Opening and persistent world (active): the opening movie and
    wakeup, Doc Mitchell’s character creation, leaving for Goodsprings, and
    saving and reloading with all state intact.
  • [ ] M2: Core gameplay loop (active alongside M1): Sunny’s tutorial
    and a Goodsprings quest branch: movement, weapons, damage, AI, dialogue,
    loot, trade, progression and V.A.T.S.
  • [ ] M3: Base-game systems and campaign: coverage of quests, creatures,
    weapons, effects, factions, companions, travel and menus, up to campaign
    completion.
  • [ ] M4: Stability and performance: long play without crashes or lost
    state, with measured frame times and streaming.
  • [ ] M5: DLC and mods: official DLC and documented plugin, archive and
    script-extension behaviour.
  • [ ] M6: VR: shared simulation with independent aim and views, tested on
    a headset.

What plays today (October 2026): Doc Mitchell’s house and his walk to the
door, Goodsprings with its people going about their routines, and two
Goodsprings quests driven by their own scripts: Back in the Saddle (Sunny’s
tutorial) and Ghost Town Gunfight. Along the way: NPC combat, animation and
navigation, dialogue, barter, the Pip-Boy, radio, physics and ragdolls,
terminals and hacking; crafting, Caravan and parts of Dead Money are in but
mostly checked by tests so far. These
three routes are replayed automatically on every change
(scripts/acceptance.ps1). Much of this was built before the engine port
and will be replaced, system by system, by the translated code.

What it isn’t yet: a complete playthrough. Parts of the routes are still
driven by console lines, the face editor isn’t built, and nothing has been
compared side by side with the original game across a whole route. Native
NVSE plugin DLLs are not supported, original-game saves can’t be loaded,
and VR and performance targets have not been validated. The open work is
in docs/TASKS.md.

Quick start

Play a test build

Download a Windows x64 ZIP from
Releases, extract it, and run
Play.cmd. Point it at your own Fallout New Vegas\Data folder. Read
docs/PLAYTESTING.md first.

Build from source

Install stable Rust, then:

# Core workspace: readers, game rules, nvinspect
cargo build --release
cargo test --workspace

# The Bevy app (separate workspace)
cd viewer
cargo run --release -- "<path to Fallout New Vegas\Data>" GSDocMitchellHouse

The core crates and their tests need no game files. Running the viewer and
nvinspect on real assets needs your Data folder. To replay the
acceptance routes (Windows, PowerShell):

powershell -File scripts\acceptance.ps1 -Data "<path to Fallout New Vegas\Data>" -Build

Windows is the tested platform. Native Linux and macOS (Metal) support are
in open pull requests.

Documentation

Read this For
CONTRIBUTING.md How to contribute: claiming tasks, pull requests, forks
docs/TASKS.md Open tasks: major systems (claim on GitHub) and the maintainer’s list
docs/MILESTONES.md Active work, blockers, evidence and the next action
docs/ENGINE_PORT_PLAN.md, docs/LEDGER.md The engine port: plan, phases, and what is translated so far
docs/ENGINE_CRATE.md, docs/FRAME_SKELETON.md How translated code is written and tested; the per-frame order
docs/METHODOLOGY.md How the game’s program is read and reimplemented, with sources
docs/adr/ Decisions: method, symbols, decompiled code, tools, the engine memory model
docs/RESEARCH_WORKFLOW.md Day-to-day research steps and provenance
research/ghidra, research/nv-oracle The research tools and how to run them
docs/TECHNICAL_REFERENCE.md Detailed feature descriptions
docs/OPENING.md, docs/OPENING_LOOK_IK.md, docs/FACE_CREATION.md, docs/PERSISTENCE.md, docs/VIGOR.md M1 topic findings
docs/GOODSPRINGS_ROUTE.md, docs/PACKAGES.md, docs/PATHING.md, docs/NPC_COMBAT.md, docs/ANIMATION.md, docs/DIALOGUE.md, docs/PHYSICS.md, docs/WEAPON_EFFECTS.md, docs/PIPBOY.md M2 topic findings (each says what’s traced, tested and missing)
docs/CONTRIB_CHAZM.md, docs/CONTRIB_PLAYCON.md, docs/DEAD_MONEY.md Contributors’ merged work
docs/VR.md VR boundaries and proposals
docs/PLAYTESTING.md, docs/MAINTAINING.md Testing builds and maintaining releases

Contributing

nv-rs is maintained by slaterain and welcomes contributors (and their
AI agents). The way in:

  1. Read CONTRIBUTING.md and AGENTS.md, and
    give both to your agent.
  2. Claim a task: the major systems in docs/TASKS.md are
    GitHub issues titled [task] …; comment Claiming this before you
    start.
  3. Work in a fork on a topic branch from the latest main, and open a
    small pull request against main that passes the checks and the
    acceptance routes.

Where help matters most now: with the game’s own code being ported
system by system, hand-written gameplay logic (quest scripts, AI, combat
rules, menus) will be replaced as the translated systems come online. The
most useful contributions are platform support, acceptance routes and
playthrough tests, research into how the original behaves, tools, and bug
reports from test builds, especially anything that behaves differently from
the original game.

Already have work in a fork? Sync your fork first, then follow
“Already working in a fork?”
to get your work claimed, rebased and into a pull request.

Final decisions rest with the maintainer
(docs/GOVERNANCE.md).

Original code is dual-licensed under MIT or
Apache-2.0, at your option. The licence covers only original
work. Fallout and Fallout: New Vegas are trademarks of their respective owners.
Read LEGAL.md for the full notice, including how material learned
from the game’s program is handled.

License and provenance

The README and its translation retain MIT terms. Changes comprise translation, links and formatting. Editable Markdown, the original README, LICENSE and NOTICE files are included in the linked bundle. This grants no rights to the original games, their assets or trademarks.

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