GitHub - openOMSI-org/openOMSI: OMSI 2 recreated from scratch in Rust, compatible with every map and mod (requires the original OMSI 2)

openOMSI is a from-scratch recreation of the bus simulator OMSI 2, written in Rust: 64-bit, multithreaded, with a modern renderer (Metal / Vulkan / DirectX 12 through wgpu). It loads the existing OMSI 2 maps, buses, scenery and mods as they are.

What you get

• Your OMSI 2 content, unchanged - maps, buses, AI traffic, scenery, scripts, timetables, HOF files, weather and plugins load the way OMSI 2.2.032 loads them. The OMSI 2 folder is never written to.
• A new engine - 64-bit (no 2 GB limit), tiles and textures loaded on worker threads, four graphics modes from Vanilla (looks like OMSI 2) to Enhanced+ (physically based lighting with ray-traced shadows and reflections).
• A launcher - pick a map, line, tour, bus and livery on one screen with a route map and a live bus preview; mods from a folder or a .zip/.7z/.rar; keys and game controllers (wheels, pedals, force feedback); updates on a Stable or Beta channel.
• Multiplayer - LAN sessions and a dedicated server (docs/SERVER.md).
• Every platform - Windows, macOS, Linux and Android; VR through OpenXR on Windows (docs/VR.md).
• More for modders - PBR materials, larger textures, more lights, and plugins in Lua or compiled .oop (Lua or WebAssembly), plus OMSI's own plugin DLLs on Windows.

Download

The newest stable version is always at Releases → Latest and on the website. Newer, untested builds are published as Pre-release (beta) on the Releases page.

SHA256SUMS in each release lists the checksums of all files.

The launcher keeps itself up to date: when a newer version is out it offers it at the start and installs it with your yes. Settings → General → Updates chooses the channel (Stable or Beta), turns the check off or installs without asking.

Installation

You need OMSI 2 installed (Steam or retail) with its stock content.

1. Install it. On Windows the -setup.exe installs openOMSI into your user folder (%LOCALAPPDATA%\Programs\openOMSI) with a Start menu entry; on macOS open the .dmg and drag openOMSI.app onto Applications. The .zip (Linux, or the portable Windows and macOS version) goes into a folder of its own that you can write to (your Documents, a games folder, or the OMSI 2 folder itself) - not Program Files, where the launcher cannot update itself.
2. Start it.
   • Windows: openOMSI in the Start menu (or openomsi.exe). SmartScreen may warn about an unknown app: More info → Run anyway.
   • macOS: openOMSI.app. If macOS refuses an app from the internet: right-click → Open → Open, or run xattr -dr com.apple.quarantine /path/to/openOMSI.app once.
   • Linux: ./openomsi (chmod +x openomsi first if needed). It needs a Vulkan or OpenGL driver (Mesa: mesa-vulkan-drivers, or your GPU vendor's driver), and WebKitGTK 4.1 for the launcher window (libwebkit2gtk-4.1-0 on Debian/Ubuntu, webkit2gtk4.1 on Fedora, webkit2gtk-4.1 on Arch; for the Steam Deck see the user guide).
   • Android: see docs/ANDROID.md - the OMSI 2 folder is copied onto the device first.
3. Find OMSI 2. The launcher usually finds the installation by itself (Steam libraries and the usual folders). If not, open Setup, press Browse… beside OMSI 2 folder, pick the folder with Omsi.exe, maps and Vehicles in it (Steam: …\Steam\steamapps\common\OMSI 2) and press Save.
4. Drive: choose a map, line, tour and bus on the Drive page and press Start the duty.

Mods are installed on the Mods page (a folder or an archive, or dropped onto the window) or put into the Mods folder next to the game.

When something goes wrong

• "OMSI 2 was not found" - choose the folder under Setup (step 3); when it is not saved, the message says what the chosen folder lacks.
• The game closes after a few seconds, or "the graphics device was lost" - update the graphics driver (from NVIDIA, AMD or Intel, not the one Windows installs). On Windows, Settings → Graphics → Graphics API can switch to DirectX 12, OpenGL or ANGLE (DirectX 11).
• An older graphics card - openOMSI falls back to another graphics API by itself; the same setting chooses one by hand.
• Stuck at a bridge or an invisible wall on a mod map - Esc → Options → Collisions with objects off (also under Settings → Gameplay).
• Multiplayer: you do not meet the others - every player needs the host's map. A map installed through the Mods page is passed on; one in the OMSI 2 folder is not.
• Keys do not do what you set - the Controls page shows which driving keys are in use (Settings → Driving → Driving keys); a key changed there takes effect at once.
• Anything else - when the game ends on an error, the launcher shows it with Copy report and Report on GitHub. Logs are in ~/.openomsi (Windows: C:\Users\<you>\.openomsi), game.log for the last game. Settings → General → Support → Support package saves a support package into ~/.openomsi (openomsi --export-diagnostics <file.zip> does the same from the command line): system, graphics card, driver, settings, controllers, last map and bus - no paths, names, chat or addresses. Nothing is sent; look inside before you attach it to an issue.

Goals

1. 1:1 behaviour. Every content format of the original loads and behaves as in OMSI 2.2.032. Existing maps and mods work unchanged.
2. No original code or assets. Nothing from the original is copied; the formats are described in docs/FORMATS.md.
3. A better engine. 64-bit, multithreaded, multiplayer, and every platform.

Documentation

The documentation is on the website, https://openomsi.org/, and in docs/:

Building from source

git clone https://github.com/openOMSI-org/openOMSI.git && cd openOMSI
scripts/build-macos.sh        # macOS   → dist/macos/openOMSI.app
scripts\build-windows.cmd     # Windows → dist\windows\openomsi.exe
scripts/build-linux.sh        # Linux   → dist/linux/openomsi
scripts/build-android.sh      # Android → dist/android/openOMSI-<version>.apk
scripts/build-server.sh       # server  → dist/server

Needs the latest Rust stable and the platform's C toolchain (on Linux also the WebKitGTK 4.1 headers for the launcher); details in docs/BUILDING.md.

Repository layout

openOMSI/
├── crates/        the game, one crate per subsystem (omsi-app is the program `openomsi`;
│                  formats, scripts, simulation, renderer, sound, network, plugins, launcher data)
├── launcher/      the launcher window (Tauri; web UI in launcher/ui)
├── android/       the Android app wrapper
├── apple/         the iPhone, iPad and Mac app wrapper (SwiftUI, not released yet)
├── services/      the "playing now" counter
├── tools/         omsi-check (format coverage), avatar and ambience pack builders, voice chat plugin
├── scripts/       build scripts for every platform, version.sh, release notes
├── assets/        fonts, icons, logos
├── docs/          documentation (also published on the website)
├── site/          the website
├── release/       health.json: released versions known to be broken
└── VERSION        MAJOR.MINOR of the next release

Contributing

Issues and pull requests are welcome - see CONTRIBUTING.md; how the project is run, reviewed and released is in GOVERNANCE.md.

Support

openOMSI is made in free time. If you enjoy it and want to help it along, you can buy me a coffee or support it on Ko-fi - thank you!

Acknowledgements

Some ideas and fixes in openOMSI date back to the public work of neoOMSI: their reports and pull requests pointed at bugs and features that we then implemented in our own code. Thank you.

License

openOMSI is released under the GNU Affero General Public License, version 3 only (AGPL-3.0-only). The historical MIT copyright and permission notice is retained in LICENSE; earlier MIT releases keep their terms. Third-party files keep their own licenses. The launcher's bus preview encodes its pictures with jpeg-encoder: this software is based in part on the work of the Independent JPEG Group. The openOMSI name and original project logos are marks of usonskyyyy, who created the original codebase; see TRADEMARKS.md. The official organization is openOMSI.org (openOMSI-org). OMSI and OMSI 2 are trademarks of their respective owners. openOMSI is an independent project and is not affiliated with them.