I am trying to add/remove furniture from the library and followed the instructions in the initial post.

- moved Furniture.jar from C:\Programme\Sweet Home 3D\lib to different directory
- made some changes to the file with the editor
. opened SH3D and imported Furniture.jar.sh3d

Is it correct that no new Furniture.jar will be created in the \lib\ directory, but the imported file is saved in C:\users\xyz\Sweet Home 3D\furniture?

If so, will I need to remove that one before making further changes?

Also, there were many items missing in Furniture.jar, like outlets etc. How can I change those ones?

Great stuff, still learning...