Rigs of Rods

Rigs of Rods ("RoR") is an open source, freeware, multi-simulation game which uses soft-body physics to simulate the motion and deformation of trucks. The game is built using a specific soft-body physics engine called Beam, which simulates a network of interconnected nodes (forming the chassis and the wheels) and gives the ability to simulate deformable objects. With this engine, trucks flex and deform as you ride the terrain, which can be based on real terrain elevation data. Crashing into walls or terrain can permanently deform a vehicle.

Gameplay
Rigs of Rods was initially created as an off-road truck simulator, but has developed into a versatile physics sandbox.

Prior to version 0.28, the game was limited to typical land vehicles with wheels, but plane and boat engines have been added since. All engines allow for a wide range of customization, leaving virtually no boundaries. Vehicles are built using vertices connected by beams. Vertices (or "nodes") are influenced by the stress on the beams that connect them. If a beam is too stressed, it will deform, thus altering the associated nodes position which ultimately alters the appearance and handling of a vehicle. Vehicle configurations are stored in plain text. Simple 2D skins can be made to wrap the vehicle, and can be supplemented with static mesh objects. Recent development has allowed for static meshes to be deformed according to a skeleton of nodes, much like the system in the game 1nsane. This system is known as Flexbody, and was included in version .36.

Vehicles ride along terrains that are defined in a raw image file, such as the data found in digital elevation model which can be used to form a realistic surface. Terrains can be made using any other program that can generate a black and white raw image format. This also means that maps can be made from any image.

As a sandbox, Rigs of Rods has no fundamental gameplay goal, but newly added Lua support contributes to missions and game play interaction like the timing of checkpoints along a road or dragstrips. Recent multiplayer support has allowed up to 16 simultaneous users to interact on a playing field. Common activities include off-roading, racing, crashing and casual play.

Critical reception
Physicist Brian Beckman described Rigs of Rods as "one of the best driving simulations I have ever seen." Rigs of Rods was featured in PC Gamer UK in the Christmas 2007 edition. French magazine MicroSim previewed Rigs of Rods in their June 2008 issue. Rigs of Rods author, Pierre-Michel Ricordel, was invited to talk about the game at the French convention, Libre Software Meeting on July 10, 2009.