Continuing the discussion from Some cool examples of my own:

That’s is most easily done in LayOut. You can draw a shape in front of the viewport whose top edge follows the terrain line and covers the foundation below ground. Give the shape white fill and no stroke. Alternative, you could draw a shape that outlines what you want to show of the viewport and use it as a clipping mask.


Thanks a lot DaveR! Sadly the Performance in Layout is very slow (with my building with lots of details, 200MB). For now I decided to export my Elevations as png and open and work on them in Photoshop.