The Reset Gazebo transport API is exposed to allow resetting simulation to time zero. It's possible to call this API using the command line or through the GUI. In addition to the API, we have also expanded the simulation system API with a Reset interface.
Reset interface
System authors may now choose to implement the Reset interface to have a more intelligent reset process (avoiding reloading assets or regenerating scene graphs being the motivating examples). Since this interface is opt-in, systems that don't implement the API will still be reset via destruction and reconstruction. The physics and rendering systems are the first two to implement this optimized reset functionality, with more to come as it makes sense to.
Following the tutorial Create System Plugins we should implement ISystemReset interface.
Transport API
To call the reset transport API we should call the service /world/default/control and fill the request message type gz.msgs.WorldControl, this service return a gz.msgs.Boolean with the status of the reset (true is everything was fine, false otherwise)
The WorldControl message now contains a reset field that we should filled if we want to reset the world:
GUI
We included a new button in the World Control plugin allowing to reset the simulation from the GUI
