Hi everyone now i am making the washbasin, and when i make the bottom half of the washbasin, i meet a problem that is i need to cutting and keep that state on the circular surface, i tried to use the void sweep, but no matter what i tried many times that always fails, so anyone can tell me how to use the void sweep to cutting the hemisphere ?
The cad picture is under the below.

And i tried these operation like below picture.



Thanks.