High Quality Content by WIKIPEDIA articles! 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, vehicles and their loads flex and deform as stresses are applied. Crashing into walls or terrain can permanently deform a vehicle.