Polylines coud be elevated but not (yet) from a user interface.

You're right! I did see the polyline code some time ago, but I did completely forgot the elevation parameter was already there [#-o]

@mirakels
I think the better option would be to ask Tobias to add this feature to his plugin.

Example for heating

Very nice result! When I first released the Wirings plugin I started a poll to know if users would have appreciated a feature to automatically generate solid pipes from the wirings, but I got very few replies so I decided to not work on this feature.

have to find a way (if any) to add new type of objects to xml file to be able to be computed by any installation.
I'm also interested in this for times when I will make some new kind of objects with specific characteristics.

I'm curious about other use cases for this feature, if you wish to go deeper you can start a new topic, I would be happy to discuss about it.