Section views showing up blank

I have two overlapping surfaces where I want to cut sections to show the difference between the two. I created an alignment through the surfaces, then created three sample lines where I want the sections to be. I then created a section view for each sample line using the default values for the standard, ootb section-view style (this is just a quick-and-dirty, in-house exercise). I get an empty grid as a result, no profile representation of my two surfaces. All my ranges are set to automatic. I've never had this happen before and I'm not sure what went wrong.

Edit: I found the solution myself, here: https://forums.autodesk.com/t5/civil...s/td-p/5455982