Hello, can someone help me. I want to make the “Bell-shape” a hole into the solid square.
Thank you so much in advance.
Make a hole.3dm (3.4 MB)
when you write a hole do you mean like this?
Make a hole.3dm (375.0 KB)
Hello Astrid. First of all thank you for your answer. No unfortunately not. I mean a real hole. like that the “Bell” Shape is in the square and the square is complete around the Bell. I need this to build a mould.
That’s called a “non-manifold” solid and is not considered “good” geometry in Rhino. You don’t need to do this to make a mold, since the mold will be split. If you “actually” need this, there are ways of doing it.
if that is what you need then type NonmanifoldMerge in your command line and choose the bell and sqaure. In general non manifold merges should be avoided.
How are you going to pour the material into that mold and get the part out afterwards?
Thank you Astrid, this was exactly what I was looking for!! 
Assuming you want add holes to let material in and air out, then you don’t need to make a non-manifold mould. Just add sprues long enough to pass outside the block to the bell before you Boolean subtract it from the box.