Rigs of Rods is an open source vehicle simulator licensed under the GNU General Public License version 3. What makes Rigs of Rods different to most simulators is its unique soft-body physics: vehicles, machines, objects, etc. are simulated in real-time as flexible soft-body objects, giving the simulation an extremely accurate behavior which entirely depends on the physical construction of the vehicles or objects you create. The community contributes greatly to the game, giving it a vast selection of vehicles and terrains from which you can choose.