Rigs of Rods deploys its own soft-body, multi-threaded physics engine and is designed to be able to simulate just about anything in the world and provide a realistic physics experience whether it be boats, planes, or vehicles. While the physics engine is all done in-house, the graphics engine is based upon OGRE. One of the developers described Rigs of Rods to us as "I can tell you that its physics simulation fidelity is beyond anything else closed source or open source existing right now. And it'll become better." Speaking of getting better, the RoR developers are looking at adding OpenCL and CUDA support for offloading more of their physics work to the GPU. Anyhow, it's now easier to try out Rigs of Rods for yourself as the first release in a long while has now been made available.
This developer, Lefteris Stamatogiannakis, also elaborated on what he believes makes this open-source simulator special:
It can already simulate cars/trucks/cranes/airplanes/boats, and all these inside a cohesive framework. If a designer designs something that "looks" like a car, it'll behave like a car.
There is no programmer/god specifying how a car should behave in a "macro" fashion. All simulation is done on the "micro" level, simulating the interaction of "matter particles"/nodes. From this micro-simulation, macro behavior arises.
Above fact, makes it very easy for designers to realize their constructs, and have them behave correctly. This fact has already resulted in a large number of drivable entities offered from the RoR repository.
In addition RoR is optimized heavily (by others before me, and lately, me), for one CPU processing. There are all the usual optimizations, and in addition some more exotic optimizations (approximate math calculations), working in there so as for a single processor to be able to calculate all physics at 2000 steps/sec in real time.
Unfortunately there hasn't been a new Rigs of Rods release in a while so interested users Linux users (Rigs of Rods is also available for Mac OS X and Windows too) have had to build the source via the latest SVN revision. However, a new release is being prepared.
Thomas Fischer, the Rigs of Rods release manager, has just tagged version 0.37-r1. Those wanting to try out this snapshot of the GPL-licensed physics simulator can find the code at SourceForge (web-viewer).
Stay tuned as we continue to explore Rigs of Rods. If you end up giving it a try let us know how you like it within our forums.