openOMSI vs. OMSI 2: The Key Differences Compared!

What is the difference between openOMSI and OMSI 2?

The biggest difference lies beneath the surface. OMSI 2 is the original complete game, while openOMSI is a newly developed runtime environment for existing OMSI content. openOMSI therefore does not itself contain any original maps, buses or add-ons, but still requires an existing OMSI 2 installation.

The goal is not to reinvent the OMSI world. Instead, familiar maps, vehicles, timetables, scripts, HOF files, sounds, objects and mods should continue to be used wherever possible. As a result, much may look familiar to players at first glance, even though the engine underneath works completely differently.

Is openOMSI simply a mod for OMSI 2?

No. openOMSI is not a conventional OMSI 2 mod, nor is it a patch that changes a few files in the old engine.

The technical foundation is being redeveloped independently. openOMSI is written in Rust and attempts to replicate the file formats and behavior of OMSI 2. The original engine itself is not used further in the process.

This means that openOMSI differs significantly, for example, from the well-known 4GB patch. The latter does not change the fundamental architecture of OMSI 2, but expands the usable address space of the existing 32-bit application. openOMSI, by contrast, is built directly on a new 64-bit runtime environment.

Why does openOMSI use 64-bit architecture?

OMSI 2 technically dates back to a time when 32-bit applications were still common. This results in significantly stricter memory limits than with modern 64-bit programs.

openOMSI, on the other hand, has a 64-bit address space and is therefore not bound by the classic memory limit of the old OMSI engine. This can become particularly relevant for large maps, extensive vehicles and many high-resolution textures.

However, 64-bit architecture does not automatically mean more FPS. The frame rate still depends on many factors: CPU performance, graphics card, scripts, AI traffic, map layout and rendering all play a role. The initial advantage is that openOMSI works on a more modern technical foundation and can manage significantly larger amounts of memory.

openOMSI vs. OMSI 2 in a direct comparison

What changes with rendering?

OMSI 2 uses its original rendering architecture. openOMSI, by contrast, uses wgpu and can use modern graphics APIs such as DirectX 12, Vulkan and Metal through it.

However, this does not mean that every old OMSI map will suddenly look like a current AAA game. A normal OMSI building with an old texture initially remains exactly that building with that texture.

The new engine does, however, open up additional possibilities. For example, openOMSI supports modern material information such as normal maps, roughness, metalness and ambient occlusion. Significantly larger textures are also technically possible. This gives modders additional room to work without existing OMSI content having to be recreated from scratch.

Will openOMSI automatically be faster than OMSI 2?

Not across the board. openOMSI has a more modern technical foundation and is more strongly designed for multithreading. Map data and textures can, for example, be processed using additional worker threads.

However, this does not automatically solve every performance bottleneck. OMSI content can be very complex, and extensive scripts or densely populated maps in particular still require processing power.

In addition, openOMSI is still in active development. Performance can therefore change between different builds, and some areas have not yet been fully optimized.

The technical difference nevertheless remains considerable: openOMSI was designed for modern hardware and multiple threads from the outset, while OMSI 2 is based on a significantly older architecture.

Do the same maps and buses work?

That is precisely one of openOMSI's most important goals. Existing OMSI maps and vehicles should continue to be used wherever possible without conversion .

openOMSI accesses the existing OMSI 2 installation for this purpose. The familiar folders such as maps, Vehicles, Sceneryobjects, Splines, Fonts and Sounds therefore remain relevant.

At present, however, this does not mean that every piece of content works in a completely identical way. Individual vehicles may have problems with scripts, displays, dynamic textures or special functions. Certain objects or special functions may also still behave differently on maps.

OMSI 2 remains the reference in this respect for now, because all content was originally developed for this engine. openOMSI is working to replicate this behavior as completely as possible.

Does openOMSI have multiplayer?

Yes. The original OMSI 2 has no integrated conventional multiplayer, whereas openOMSI does.

Several players can travel on the same map within a shared LAN session. Dedicated server builds also exist, which can host a session without a full game window.

This gives openOMSI possibilities that OMSI 2 itself never directly offered. Shared route trips, community events or servers for virtual transport companies thus become technically possible in principle.

The same applies here, however: openOMSI is still in Early Release. Multiplayer is available, but it should not be confused with a fully developed online MMO or a large public server network.

What changes with OMSI mods?

Over many years, OMSI 2 has built up a huge modding landscape. Classic installation generally works through familiar folders such as maps, Vehicles, Sceneryobjects or Splines.

openOMSI does not want to replace this content, but offers additional mod management in the launcher. Mods can be integrated separately from the actual OMSI installation, for example through folders or ZIP files.

As a result, the original OMSI 2 installation does not have to be changed for every openOMSI mod. This makes testing and managing additional content more straightforward.

However, this does not create complete automatic dependency management. If a map is missing an object package or a bus requires additional files, they must still be available.

Which platforms does openOMSI run on?

OMSI 2 is primarily a Windows game. openOMSI, by contrast, has pursued a cross-platform approach from the outset.

Builds currently exist for Windows, Linux, macOS and Android. There are also x64 and ARM64 variants for various systems. Android is particularly unusual in this regard, because the engine actually runs natively there rather than merely streaming a Windows PC to the smartphone.

This does not automatically mean that every piece of OMSI content works equally well on every platform. Mobile devices in particular impose significantly tighter limits on memory, graphics performance and cooling. Technically, however, openOMSI is much less tied to a single platform than the original.

Where can openOMSI be downloaded?

Anyone who wants to try openOMSI can find the current builds directly via the project's official release page.

Download:
https://github.com/turbo-devv/openOMSI/releases

The versions currently available for Windows and other supported platforms are provided there. For a standard Windows PC with an Intel or AMD processor, the Windows x64 version is generally relevant.

One thing remains important: openOMSI is not a standalone free OMSI 2. You still need the corresponding OMSI content from a legally obtained installation.

Does OMSI 2 have to remain installed for openOMSI?

Yes. openOMSI does not include any original OMSI content itself.

Anyone who wants to use Grundorf, Berlin-Spandau, the standard buses or purchased add-ons still needs the corresponding files from a legally obtained OMSI 2 installation.

So openOMSI does not replace owning OMSI 2. Rather, it replaces the technical environment that loads and runs this content.

This is precisely why the designation “OMSI 3” is only useful as an emphatic comparison. openOMSI is not an official OMSI 3 and not a standalone commercial successor.

Is openOMSI better than OMSI 2?

A blanket answer currently makes little sense.

In several areas, openOMSI has the more modern technical foundation: 64-bit architecture, modern graphics APIs, multithreading, multiple operating systems, multiplayer, dedicated servers and more modern mod management.

OMSI 2, on the other hand, has the decisive advantage of being established for years, with all existing content originally developed specifically for this engine. Anyone who wants maximum compatibility with a large mod collection will therefore currently encounter significantly fewer unknown edge cases.

openOMSI is also explicitly still in an Early Release. Features may be missing, errors may occur and behavior may change between new builds.

The two systems are therefore currently less in a classic competitive relationship than the term “openOMSI vs. OMSI 2” might initially suggest. openOMSI still needs OMSI 2 as its content base while simultaneously attempting to take over more and more of the original engine's tasks.

Can openOMSI replace OMSI 2?

Not across the board at present.

For certain maps, buses or use cases, openOMSI can already serve as an alternative way to launch OMSI content. It also offers features such as Android support and multiplayer, which the original does not offer at all in this form.

Those who, on the other hand, expect to transfer their entire collection built up over many years and immediately use every bus, every plugin and every map exactly as in OMSI 2 must continue to expect differences.

In the long term, however, openOMSI is pursuing precisely this ambitious goal: to replicate as many functions of the original engine as possible while modernizing its technical foundation at the same time.

This creates an unusual situation. openOMSI is not trying simply to leave OMSI 2 behind. Instead, the exact huge world of maps, buses and mods is meant to be preserved while a completely new engine gradually takes over underneath.

The most important difference between openOMSI and OMSI 2 can therefore be summed up quite simply: the content should remain as much the same as possible—the technology underneath should not.

What would be the decisive point for you to switch: 64-bit architecture, better performance, multiplayer—or would practically every OMSI mod first have to work flawlessly?