Hi Yanus3D,

re:
> Yes!
> That`s correct export
> One layer only.

Great! To get that result, make sure "Combine same named objects" is turned on here under Options dialog > Import/Export :



Then set the objects you want combined to have the same object name before exporting.

To do that, use Ctrl+A to select all, then click on the object name here and set to any name other than blank:



If you then generate your .lwo file you should get the same one layer result.

- Michael