How can I create a section plane?


I want to create a section plane through a scene such that the entire scene on one side of the plane is invisible, allowing the other half of the model to be viewed. An example of the effect I’m after is here - YouTube at around 1:26 where a horizontal plane cuts through a building, allowing the lower part of the building to be seen while the upper part is invisible. My scenes consist almost entirely of procedural meshes. I have looked around, and camera near and far clip planes seem to offer the ability to split a scene, and make part of it invisible, but I want to be able to control the section plane independently of any camera, so that the camera can move around and view the sectioned scene from any direction.
I’d be grateful if anyone can offer any pointers about how to do this - either in blueprint or c++.

Many thanks in advance!