thank you for your detailed response, I am trying this as I type.
it was a great success, it worked as you said but there were still a couple of problems, when I exported and imported again my craft (a plane) as mu there were no differences in the model but when I exported it in stl and loaded in cura to slice it to 3d print it it was missing some parts like an engine, the nose cone and a large chunk of its left side and I dont know why but I was able to solve this loading the stl in my cad program and creating from scratch (and copy pasting) the missing parts
tomorrow I'll try to print it and if it is successfull it will be all thanks to you! thanks again, a lot