Fallout 1 & 2 Engine and File Format Documentation

This repository contains static HTML documentation for Fallout 1 and Fallout 2 engine behavior, resource formats, modding data, reverse-engineering notes, and tooling references.

The hosted copy is available at:

https://fodev.net/files/fo2/

Audience

These notes are intended for:

• mod authors editing Fallout 1/2 data files
• tool authors writing readers, validators, converters, or editors
• reverse engineers comparing executable behavior with community notes
• maintainers documenting sfall, Fallout 2 Community Edition, and related tools

The documentation is mostly written from a practical compatibility point of view: what the game, tools, and common modding workflows actually read, write, or depend on.

Where to Start

• index.html is the main entry point and resource index.
• File formats are documented in pages such as dat.html, frm.html, pro.html, map.html, int.html, and ssl.html.
• Executable and reverse-engineering references include structs.html, symbols.html, fallout2_re.html, and sfall_refs.html.
• Tool and project lists live in tools.html and mods.html.

Useful reading paths:

• Art and interface work: DAT, FRM, PAL/COL, LST, PRO
• Script work: SSL, INT, MSG, SCRIPTS.LST, MAP
• Data editing: DAT, PRO, MAP, MSG, GAM, CFG/INI
• Reverse engineering: structures, symbols, Fallout 2 RE references, sfall refs

Repository Shape

The published site is static HTML plus CSS. Documentation pages are authored in Markdown and generated into _site/.

• style.css - shared page styling
• img/ - images used by pages
• highslide/ - bundled image viewer assets used by older pages
• symbols/ - supporting symbol/reference pages
• fallout2.sym - symbol data
• content/ - Markdown sources, data files, and templates
• tools/FoDocs.Generator/ - .NET 10 static site generator

Pages should be reviewed from _site/ after running the generator.

Generating the Site

Markdown pages in content/pages are rendered into the output site and keep the public .html URLs used by the hosted copy.

Requirements:

• .NET 10 SDK

Generate the site:

dotnet run --project tools/FoDocs.Generator -- --clean

The output is written to _site/. Generated files and .NET build artifacts are ignored by Git.

Current generated pages:

• aaf.html from content/pages/aaf.md
• acm.html from content/pages/acm.md
• ai_txt.html from content/pages/ai_txt.md
• anim_names.html from content/pages/anim_names.md
• bio.html from content/pages/bio.md
• cfg.html from content/pages/cfg.md
• criticals.html from content/pages/criticals.md
• dat.html from content/pages/dat.md
• elevators.html from content/pages/elevators.md
• fallout2_re.html from content/pages/fallout2_re.md and content/data/fallout2_re.tsv
• fo1in2.html from content/pages/fo1in2.md
• fo_colors.html from content/pages/fo_colors.md
• fon.html from content/pages/fon.md
• frm.html from content/pages/frm.md
• gam.html from content/pages/gam.md
• gcd.html from content/pages/gcd.md
• hrp.html from content/pages/hrp.md
• index.html from content/pages/index.md
• int.html from content/pages/int.md
• lip.html from content/pages/lip.md
• lst.html from content/pages/lst.md
• map.html from content/pages/map.md
• mods.html from content/pages/mods.md
• msk.html from content/pages/msk.md
• msg.html from content/pages/msg.md
• mve.html from content/pages/mve.md
• pal.html from content/pages/pal.md
• party_txt.html from content/pages/party_txt.md
• pipboy_txt.html from content/pages/pipboy_txt.md
• pro.html from content/pages/pro.md
• rix.html from content/pages/rix.md
• savegame.html from content/pages/savegame.md
• scripts_lst.html from content/pages/scripts_lst.md
• sfall_refs.html from content/pages/sfall_refs.md and content/data/sfall_refs.tsv
• ssl.html from content/pages/ssl.md
• structs.html from content/pages/structs.md
• symbols.html from content/pages/symbols.md and content/data/symbols.tsv
• sve.html from content/pages/sve.md
• tools.html from content/pages/tools.md
• worldmap_config.html from content/pages/worldmap_config.md
• worldmap_dat.html from content/pages/worldmap_dat.md
• docs-generator.html from content/pages/docs-generator.md

Source work should happen under content/pages, and the generated _site/ directory is the best target for checking pages before publishing.

Contributing

See CONTRIBUTING.md for writing conventions, source/reference expectations, and lightweight validation checks.

Good contributions include:

• clarifying ambiguous format fields
• adding verified engine behavior
• documenting cross-file dependencies
• adding small examples or validation notes
• fixing broken links, invalid markup, or stale tool references
• marking uncertain legacy notes as unverified instead of presenting them as fact

Source and Verification Notes

When possible, prefer source-backed statements and cite the relevant project or page. Common anchors include Fallout 2 Community Edition, sfall, original tools, known community writeups, and direct binary/resource inspection.

If behavior differs between Fallout 1, Fallout 2, Fallout 2 Community Edition, sfall, or a modding tool, document the distinction explicitly.