# OpenSC4: an early open-source reimplementation of SimCity 4

> Reimplements SimCity 4 as a Godot project in GDScript that reads DBPF archives, region folders and city saves from the user’s own SimCity 4 installation. The code draws a region view with city thumbnails and interface elements built from the game’s UI definitions, opens a saved city’s terrain and water in 3D, and includes a DAT explorer for previewing archive subfiles. It is an early, inactive engine case without simulation gameplay, not a playable replacement.

- Type: Case study
- Targets: Game
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-10-19
- Added to the catalog: 2026-10-29
- Original resource: <https://github.com/OpenSC4-org/OpenSC4>
- Primary source: <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/README.md>
- Catalog page: <https://awesomerea.org/resources/opensc4-simcity-4-reimplementation-case/>
- Record JSON: <https://awesomerea.org/resources/opensc4-simcity-4-reimplementation-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/opensc4-simcity-4-reimplementation-case/index.md)

## Requirements & limits

- The reviewed main snapshot (2024-03-29) only added a README and a Discord invite; the last code change dates from 2023-02-17, and the repository has no releases or tags. README describes an open source “clone” meant to use modern hardware and run on other platforms. The code covers DBPF parsing, a region view for the hard-coded Timbuktu region, a city terrain view and the DAT explorer, with no zoning, budget or growth simulation.
- Needs the user’s own SimCity 4 installation: the boot screen asks for its folder and checks for SimCity 4.ini, Sound.dat, Intro.dat, SimCity_1.dat to SimCity_5.dat and EP1.dat, then reads .sc4 city saves, config.bmp and region music from that folder. .gitignore excludes SimCity 4 data, although the tree contains a “Graphics Rules.sgr.backup” text file whose header says SC4Launcher generated it.
- Runs from source in the Godot editor: README’s setup is to install Godot, import the cloned project and run it, without naming a version. project.godot uses config_version 4 and the scripts call Godot 3 APIs such as yield and Directory; no export presets or packaged builds are provided.
- The repository has no tests or CI workflows and publishes no comparison with SimCity 4’s behaviour or output.
- GitHub detects no license and the tree has no license file; nine GDScript files carry AGPL-3.0-or-later headers for “The OpenSC4 contributors” (2023), and utils/logger.gd is MIT-licensed code from KOBUGE Games’ godot-logger. SimCity 4 and its data keep their owners’ rights.

## Primary sources

1. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/README.md>
2. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/BootScreen.gd>
3. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/Region.gd>
4. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/CityView/CityScene/City.gd>
5. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/DATExplorer/SubfilePreview.gd>
6. <https://github.com/OpenSC4-org/OpenSC4/tree/fdc90c33e6e012b8c825f20ee10c51f55796df39/addons/dbpf>
7. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/project.godot>
8. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/.gitignore>
9. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/Core.gd>
10. <https://github.com/OpenSC4-org/OpenSC4/blob/fdc90c33e6e012b8c825f20ee10c51f55796df39/utils/logger.gd>

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## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.