I already have an `hemisphere.obj` 3D model. But I'm trying to build a half-hemisphere (quarter sphere) model. How can I do that? What is the easiest way to do that?

Generally, is there any easy way to create 1/n of sphere?

[![enter image description here](https://i.stack.imgur.com/VEzQP.jpg)](https://i.stack.imgur.com/VEzQP.jpg)