Implement in RobotModule in Python + load XML robot models

[rohanpsingh]

I have two questions:

• Is it possible to implement a RobotModule in Python? In the tutorial, it shows a C++ example only, so I assume it's not straightforward to do so in Python. Still, I would like to know how it could be done.

• I want to build a parser for XML models so I'd be able to something likeinit(rbd::parsers::from_xml_file(xml_path)) while creating the robot module. A, do you think it is a good idea? and, B, do you have any pointers?

[gergondet]

Hi Rohan,

Is it possible to implement a RobotModule in Python?

No but it isn't impossible to implement either.

Still, I would like to know how it could be done.

You need two pieces:

• a Python object that the user can creates that contains a RobotModule C++ object, we already have this in the bindings (ref) but the implementation does not allow you to overwrite every member in RobotModule
• a loader from Python to C++. Since RobotModule does not implement any behavior I think the simplest approach is to have a Python module similar to the Python controller but it will just instantiate a Python RobotModule object so that you can extract the C++ RobotModule from inside.

You would use the loader as such:

MainRobot: Python#my_module.MyRobot

Where MyRobot is a Python class that derives from mc_rbdyn.RobotModule that you instantiate in the Python RobotModule (and then extract the C++ RobotModule from the object)

do you think it is a good idea?

I would avoid using the name from_xml_file since it's a little too broad and you probably have a particular kind of XML model in mind (so e.g. from_mujoco_xml_file?)

do you have any pointers?

Not really. The only thing the function has to do is return a rbd::parsers::ParserResult and from there most of the work is done :)

[gergondet]

Hi @rohanpsingh

Is this still an active topic for you?

[rohanpsingh]

Hi @gergondet
Sorry I got involved with several other stuff recently so did not have time to work on this.
I started implementing your suggestions above and ultimately want to get this done, but it's currently a low priority for me.