Another does it exist or just a Wish List entry? My old software had “Invisible Walls” which were essentially 0 width walls. I used these often for positioning and dimension references.
Example: I’ve imported a Google Earth jpg as a Trace element showing some of my property, house & out buildings so that I’ll be able to add landscaping features later. Can see the ridge of the 2nd story well, so want to draw the house related to that. Since the roof also covers a porch, the actual ridge line is offset w.r.t. the building. I can draw a Line over the jpg ridge and want to position my 28 ft wall so that 9 ft are left of this Line and 19 ft are right of the line. So would like to see dimensions between the Line and each end of the wall. Yes, I know I can build a temp wall as a ridge or add a roof at this point to do this, but just seeing if there was another way with Lines or something else. Similarly, I need to locate out buildings X,Y ft from the house, so it’d be nice to have reference lines that I could just select to see the separation distance later and not have to use the Measuring tool.