Welcome to the Unofficial Fallout 4 Documentation

This project is an in-depth technical overview of the game Fallout 4 and its Creation Engine. It is intended as a reference for modders, researchers, and anyone with a technical interest in how the game works under the hood.

What's Covered

• Creation Engine — historical context and architecture of Bethesda's game engine
• Papyrus — the scripting language: syntax, engine API with 55+ native classes, interactive script dependency map, and VM internals (PEX bytecode format, all 50 opcodes)
• File Formats — byte-level specs for ESM/ESP game data records (20+ record types), BA2 archives, NIF meshes, DDS textures, BGSM/BGEM materials, and precombined mesh geometry

About this project

This documentation is an independent, fan-made resource. It is not affiliated with, endorsed by, or sponsored by Bethesda Softworks or ZeniMax Media. All content has been produced through observation of legally-owned copies of Fallout 4 and the official Creation Kit, and through analysis of file formats and runtime behavior. No leaked or otherwise unauthorized source material has been used at any point. Fallout, Fallout 4, the Creation Engine, and all related trademarks are the property of Bethesda Softworks LLC and ZeniMax Media Inc.

Disclaimer

Much of the information in this wiki was derived using artificial intelligence. The AI worked directly with the game's data and was required to validate its findings, but errors are still likely. If you spot a mistake or want to contribute, open a pull request at github.com/julianthomas04/fo4docs.