Since 2011, several labs have been working on robotics technology middleware and a software framework for robot software development, better known as Robot Operating Systems (ROS) that implement simulation solutions for Multi Open Robots Simulator Engine (MORSE). MORSE is an open-source project rendering robots in a 3D environment. It is said to be a versatile simulator for academic robotics and was born at LAAS-CNRS, a public French laboratory specialized in robotics.
This is a project driven by an active community of users and developers. It has been in the development process only for a few years and, in that time, there have been added features, reported bugs and submitted patches (http://www.openrobots.org/wiki/morse). The new version, MORSE 1.0, has been finally released. The goal was to build a realistic simulator for complex robots; it is being developed to be used in both research and teaching.
The simulation environment is extremely realistic but also adaptable to the needs of the researchers that are using it. It is, in fact, able to handle several robots at once, but is also scalable. A particularly interesting feature is the human-robot interaction (HRI) simulation. Users can navigate the scene and employ a first-person perspective while interacting with the robots.
MORSE uses Python programming language and OpenGL 3D engine. It also uses Blender, a free and open-source 3D computer graphics software product--featuring a built-in game engine--to create a realistic representation of the robots as well as carry out the HRI simulation. Blender is used to edit the 3D scenes and its game engine allows true-to-life robot representations.
MORSE is flexible enough to allow the addition of components as needed. It can support 20 classes of sensors (like cameras and scanners) as well as 15 types of actuators. Additional devices can be added by acting on the actual program. MORSE is flexible also in terms of the computing environment in which it can be run. In fact, it works on Linux but it can be used, with limitations, on OSX and Windows.
The only limitation of MORSE seems to be the fact that although highly realistic, the environment created is not physically exact; therefore it cannot be trusted when taking measurements or performing other tasks that require exact dimensions, time measurement or interaction with physical robots.