The FlightGoggles Renderer functions as a back-end that simulates exteroceptive sensors, such as cameras and distance measurements, and is based on Unity3D. The latest release binaries for Windows and Ubuntu can be found under Releases on the GitHub page.
In addition to the pre-built binaries, the FlightGoggles Renderer source code and Unity3D asset bundles are available to download. For instructions on how to use the Unity3D editor, have a look at Using the Unity3D Editor .