Hi all.
I just acomplished to make a first sucessfull test with the object spawner in squared or retangular regions, and made some screenshots of the process :
Selecting a region to fill :
Opening Object Spawner little panel ( still with only basic options ) :
The region is then filled with the object :
Another angle :

This is a very first test, but the functionality is there, I´m working on a second spawn system that will allow spawn in different shapes, or shapes created in real time by hand ( The shape creation / deform by mouse is already done, the object spawner for it, not yet ), and finally the constructor mode, to allow continous contructions like fences / walls.
After created, the spawned entities can be select normally as the other pre loaded entities, to have theyr properties changed.
The menu system is ready also.
The result layout then can be saved and reloaded at a later time.
This can easily be adapted with a dozen lines to load / unload complete levels.