I have found a very good, free Windows 3D-CAD program and will try to use it under Linux Mint 17.3 - 64bit.
The install is well done, but the Programm will check by ever start via Javaprogram the licence about internet.
Now i think it is necessery to install the java runtime from windows under playonlinux.
But i don't know how i can do this. Can anyone help?