Create a drill inside a sphere

I’d like to modelise a spheric volume, but not full, i’d like to have a thickness of 2 mm.
And, inside the volume, i’d like to make drill, like i show here.
First, i am not sure i am using the best solution for the spheric volume: i am doing four “1/4”, or quarter of volume, anf after, i’d like to assembly doing an addition boolean. But, sometimes, it doesn’t work. So, i am sure there is an easier and quiclky solution! :slight_smile:
After that, i’d like to make drill, but, as it is not a plane volume, we cant do for example boolean substraction, we have to create the mesh, in order to have a good geometry. But, after, i don’t know how to do. What i am doing, as i show here, is, step by step, using “réseau de surface” …and after “décaler surface”, 2mm, and after, addition bolean… but it is so long, and i am shure there is a best way! :slight_smile:Can you please help me? Thanks so much! :slight_smile:

Hello - it’s not clear to me yet what you mean by ‘drill’ but it looks like you’d like a sphere that is 2 units thick but has some gaps or holes - like this?


Please forgive me if I’m saying something here that you already know:

In english “Drill” has two meanings, one that could relate to Rhino and another that’s considerably different. First, it refers to the act of making a round hole and/or the tool that makes a round hole (twist drill). The other meaning is to practice some procedure, as in a “fire drill” - what to do in case of fire.

If the picture that Pascal posted is what you are after, the term would probably be “a cut” or “an opening”.