isolate a part from a 3d design and then save it separately

[GiacomoSolid]

Good morning.
as from title I would like to know if you use a functional method to be able to isolate a part of a 3d design and then be able to save it so that you can create the design from it without having to remake the design of a single piece from head.
Thank you very much in advance.

 

[MassiVonWeizen]

complicated explanation. . .
you must isolate:
part of a set?
a body of a part?

 

[GiacomoSolid]

complicated explanation. . .
you must isolate:
part of a set?
a body of a part?

I should isolate a body of a part.

 

[MassiVonWeizen]

to have separate files:
functions?save bodies
or
in the list of bodies do insert new part

if you always want the same file:
create a configuration and with the function eliminates bodies deletes all hlri other
or
do body island and save a display status

 

[MassiVonWeizen]

if you want to use the drawing already made you have to opt for configurations or display states