Thank You...
TheRestOfTheFurnitureInTheRoomplugin.jar works. But the plugin about which I spoke I thought will be able count cubic meters of walls. Exist some such pluging to get m³ of wall?

Of course, This is logic, that we have to unpack and place there the content of the package. Exactly this I made.

But in the case of the plugin which I wanted to it is RAR.
[url=http://]https://sourceforge.net/p/sweethome3d/plug-in...omputeRemainderVolume.rar[/url]

1) I downloaded the package
2 ...

Hello,
I downloaded SweetHome3D Linux version, where it runs without installation (just unpack and launch SweetHome3D script)
The application it self runs without problem.

As next step I wanted to add some the Plugin.
Here [url=http://]http://www.sweethome3d.com/pluginDeveloperGuide.jsp[/url]
I ...