Extracting a Volume from a Closed Surface

Hi Everyone, this seems like such a primitive problem but I’m banging my head as I’ve hit the wall trying to figure this out.
How do you go about extracting a volume out of a sphere so that I can print hollowed sphere with wall thickness? I tried boolean difference but since there is no tangency between two surfaces it will not ‘extract.’ Theoretically, I think it’s impossible unless the two surfaces touches each other to boolean and subtract, but how does one go about modeling something like this for 3D print?

Reason Why I’m Asking:
I have a model with closed surface. Since it fills the entire volume when being printed, I want to create some hollowed structure inside of the model to make it use less resin and more lightweight. When I simulate the print, since all I managed to do was put a closed surface inside of another closed surface without touching, it just fills the whole volume.

Hopefully this makes sense, any tips are appreciated!!!

That isn’t possible with NURBS surfaces.
It is possible with Meshes.
For NURBS, you will need to create a small “tube” that connects the inner and outer surfaces so they are a single closed polysurface, with the enclosed volume between the spheres.

Hello- many printers have a wall thickness and looser ‘infill’ for cases like this