Building OpenSim from Source

This covers getting the source and compiling it. If you just want to run it, you still need to build (OpenSim does not ship prebuilt binaries in this repository).

1. Get the source

git clone git://opensimulator.org/git/opensim
cd opensim

Or clone from the GitHub mirror if you prefer. Use a fresh checkout – do not build inside a directory with spaces in the path.

2. Generate project files

OpenSim uses prebuild to generate the .csproj/solution files from prebuild.xml.

Windows:

runprebuild.bat

Linux / macOS:

./runprebuild.sh

This produces OpenSim.sln and the per-folder project files.

3. Build

dotnet build --configuration Release OpenSim.sln

The compiled output lands in the bin/ directory. You can also open OpenSim.sln in Visual Studio and build the solution there.

4. What ends up in `bin/`

After a build, bin/ contains the executables and the default configuration files:

OpenSim / OpenSim.exe – the simulator.
Robust / Robust.exe – the grid services server (grid mode).
OpenSim.ini.example, OpenSimDefaults.ini – configuration templates.
config-include/ – includes such as Standalone.ini, Grid.ini, and their *Common.ini.example templates.
Regions/ – region definitions (Regions.ini).
OpenSim.exe.config / Robust.exe.config and runtimeconfig.template.json.

5. First run & configuration

You configure OpenSim by copying the .example files to real .ini files and editing them. The two main choices are:

Standalone – see Standalone mode.
Grid – see Grid mode.

The build itself does not need configuration; configuration happens in bin/ after the build, as described in those pages.

Troubleshooting the build

dotnet: command not found – .NET 8 is not installed or not on PATH. See Installing .NET.
Missing libgdiplus (Linux/macOS) – image-related features fail at runtime; install it as shown on the .NET page.
Build errors after a git pull – remove stale build artifacts (find . -name obj -type d -exec rm -rf {} + and similar) and re-run runprebuild.sh then dotnet build.