The "Hide obstacles in the 3D view" feature is shown here:
https://youtu.be/FrnDfMOdtPY?si=s8LQck2WY0Xi1ifD&t=29

There is also an advanced mode that allows to hide all objects behind a given polyline, it is shown here (this video has been made with an old version of the plugin, newer versions work a lot better):
https://youtu.be/wYDrdH8brsw?si=nnsMWhCaceKxwg_B&t=34

The hiding criteria is explained here:
https://www.sweethome3d.com/support/for ... t,20#53297

Cheers!