For the cross sections, I'd like to get something like shown in the attachments (first one from the same cave in Siuntio, another one from a cave in Vihti).
Both of these pictures are taken from the full 3D model, sliced up in Blender and shown in two different ways. You can actually slice the up in exactly the way you want, and you get an interesting perspective on things.
There's some difficulties, however, such as the Blender tools having been primarily made for objects and now we're dealing with spaces... it gets confused sometimes what's inside in intersection and other operators. Or maybe I'm confused. Still learning, and the 3D modelling tools have a pretty steep learning curve :-)