Repo can be found here - https://github.com/Lumak/Urho3D-Constraint6DoF
6 DoF spring2 samples: 1 - a ship on a rail example. 2 - hover bike example.
To build it, unzip/drop the repository into your Urho3D/ folder and build it the same way as you'd build the default Samples that comes with Urho3D.
Last tested using Urho3D 1.7 tag.
The MIT License (MIT)