P.S. I have Ubuntu 19.04

Hey Pascal:
You seem to have learned quite a lot about this problem of Sweet Home 3D not launching in Ubuntu.

When I run it to terminal here is what I get:

Java 3D: implicit antialiasing enabled
Java 3D ERROR : GLX extension is not supported
GLX version 1.3 or higher is required
Gtk-Message: 23:46 ...