hello there ,
there is a way you can do this:
- make a 2D poly and then divide it into segments of whatever length you need (or you can just make a 3d poly with the vertices snapped on whatever points you need in the section) ;
- convert the 2d poly into 3d poly;
- in cadtools - surface -> edit/view surface use "drape 3dpolylines" and "check drape vertices only";
- use "profile 3d polyline" and you get your desired long section.
good luck,
cr