Envire-Simulation is a Physics-Based Robotics Simulation engine that uses Envire as backend to manage, update and store the simulation objects. Envire-Simulation or Envire-Mars has its origins in the Robotics Simulator Mars. The two main differences with respect to Mars are: an Envire Based management of the simulation objects and a more modular software architecture.
The original version of Mars is based on a Main controller -NodeManager- to manage the object and its interactions with the physics simulation core -ODE in this case- and other simulation libraries (e.g. simulated motors and sensor). In order to enhance the eficciency and improve the architecture of the simulator, in Envire-Mars these functionalities were moved to plugins which can be loaded dynamically on demand. In practice, these plugins access, modify and update the Envire Transformation Graph which is stored at the core of the simulation engine and allocates the objects which the simulation tools require to compute its interactions.
Robotic simulation engines traditionaly represent the simulation environment using a different approach than the one that the robot control software uses to model the world. Using two different approaches has two clear drawbacks: one on the software engineering side and one on the robotics control side. The software engineering drawback is that multiple code providing very similar functionality (spatial-temporal representation) has to be maintained and is not homogenized. The robots control drawback is that generating simulations from real world data becomes computationally expensive: In the classical simulators this requires the implementation of converters to switch between sensor data based representations and simulation representations.
In summary, Envire Simulation builds upon the work done in Mars and achieves a better integration of the simulation environment with other components of the robotic control system by sharing the same representational structure. By sharing the same representation library the improvements on this library for other robotic application will also positively affect the simulation engine and vice-versa.