@rocioavictoria 's solution was based on using the Underlay settings but this method isn't straightforward in MEP models when the architecture is in a linked file. The underlay settings also refer to the Level below, not to a particular view so its difficult to control view settings for the underlay.
The marked solution is however to extend the bottom plane and view depth to a low enough value to cut through the walls below. You might also need to adjust the cut plane if you want to cut through the walls/doors/windows etc rather than looking down on top of them.
Post a screenshot of a section view and also your view range settings in the corresponding plan view.
