Hi Frank,

re:
> But after boolean "merge" I have to move the single objects a little bit to the outside to
> become a small gap between the objects.

The closest thing to this would be ExplodeMove like Pilou mentions:
http://moi3d.com/3.0/docs/moi_command_reference10.htm#explodemove

But the objects will move outwards from their overall bounding box center, it won't necessarily move them with a uniform gap between each piece. So to get a uniform gap you might need to use the manual movement that you've already been using.

- Michael