What is OpenSimulator

OpenSimulator is software that simulates a virtual world very similar to our own physical world.

In the picture, the OpenSimulator software is what makes the island beneath our feet solid, the water waves twinkle in the simulated sun, and the clouds drift slowly overhead. A gentle breeze blows the virtual air, making flags and cloth items flutter, and an object placed in the air will fall to the ground, just like gravity does in the real world. OpenSimulator is the collection of computer programs needed to simulate all of the simple and complex interactions that can take place in this virtual environment.

OpenSimulator is open source software,

…which means anyone is free to download and install it on their own computer or server, and anyone can look at the computer program code and edit or improve it if they want to. In fact, the OpenSimulator software is written and created by many people all over the world who work together to make the software better, and anyone who wants to help improve the software is welcome to join the community of OpenSimulator developers.

For the technically-savvy, this is the description of OpenSimulator from the official wiki:

OpenSimulator is an open source multi-platform, multi-user 3D application server. It can be used to create a virtual environment (or world) which can be accessed through a variety of clients, on multiple protocols. It also has an optional facility (the  Hypergrid) to allow users to visit other OpenSimulator installations across the web from an account on a ‘home’ OpenSimulator installation.

OpenSimulator allows virtual world developers to customize their worlds using the technologies they feel work best – we’ve designed the framework to be easily extensible. OpenSimulator is written in  C#, running both on Windows over the .NET Framework and on Unix-like machines over the  Mono framework. The source code is released under a  BSD License, a commercially friendly license to embed OpenSimulator in products. If you want to know about our development history, see  History.

Out of the box, OpenSimulator can be used to simulate virtual environments similar to  Second Life™, given that it supports the core of  SL’s messaging protocol. As such, these virtual worlds can be accessed with the regular SL viewers. However, OpenSimulator does not aim to become a clone of the Second Life server platform. Rather, the project pursues innovative feature development with an aspiration towards becoming the bare bones, but extensible, server of the 3D Web.

OpenSimulator is getting more stable as it approaches release 1.0, but we still has a few quirks; handle with care!


  • Supports online, multi-user 3D environments as small as 1 simulator or as large as thousands of simulators.
  • Supports 3D virtual spaces of variable size within one single instance.
  • Supports multiple clients and protocols – access the same world at the same time via multiple protocols.
  • Supports realtime Physics Simulation, with multiple engine options including ODE.
  • Supports clients that create 3D content in real time.
  • Supports inworld scripting using a number of different languages, including LSL/OSSL, C# and VB.NET
  • Provides unlimited ability to customize virtual world applications through the use of scene plugin modules.

For the purposes of this manual, you don’t really need to know all those technical details, it should be enough to know that OpenSimulator is the software that makes the water, land, and sky in this virtual world – and all the things you can do in it – possible!