UE5.x TemplateDecoupled C++ ArchitectureBlueprint Friendly

OSSIM

OSSIM is a desktop-environment template for Unreal Engine 5. OSSIM provides a complete, persistent OS experience with a decoupled controller-view architecture, interface-driven UI, and a suite of built-in apps.

Why Choose OSSIM?

OSSIM isn't just a UI kit, it's a template for a complete OS. It handles the "boring" parts of OS simulation, window management, process tracking, and filesystem persistence, so you can focus on building your gameplay and apps.

The OS is auto-activated: In the OSSIM_DemoMap Outliner, locate BP_ScreenOS. Inside this actor, you'll find WBP_OS_Root (inherited from UOSOrchestratorWidget). The OS automatically initializes as soon as the widget is constructed during BeginPlay.

Press the F key to toggle the view to the PC screen or enter AFK mode. You can review this behavior in the OSSIM_DemoMap Level Blueprint.

Core Strengths

Decoupled Architecture

Uses a Controller (C++) and View (UMG) pattern. Logic is strictly separated from presentation.

Blueprint Friendly

Create new OS applications entirely in Blueprints using the BlueprintApp base class.

Interface-Driven UI

Widgets implement IAppContentWidget for automatic, type-safe initialization by the OS.

Virtual Filesystem

Linux-like VFS with per-user persistence for file and directory operations.

Service Facade

Apps access OS services (VFS, Windowing, Launcher) through an unified C++ API.

Staged Session Flow

Includes Boot, Onboarding, Login, and Desktop stages out of the box.

Included Applications

OSSIM comes with a suite of functional apps that serve as both tools and code references:

File Explorer: Navigate the VFS, manage files, and launch associated apps.
Notepad: A multi-tab text editor with undo/redo and persistence.
Terminal: Command-line access to system processes and the filesystem.
Media Viewer: Integrated support for viewing images and playing videos.
Music Player: Audio playback with playlists, shuffle, repeat, and volume control.
Task Manager: Visual monitor of running apps and processes.
Calculator & Calendar: Essential desktop utilities.

Documentation Guide

Getting Started: Set up your environment and verify the core shell flow.
Architecture: Deep dive into the controller-view pattern and core subsystems.
Extending OSSIM: Learn how to build your own apps using Blueprints or C++.
Save And Session: Understand user persistence and filesystem snapshots.

OSSIM is built for developers who spend countless hours creating computer systems. It brings a fully interactive operating system directly into Unreal Engine projects, enabling everything from hacking mechanics to complete in-game desktop experiences.