Sweep 1 align question

  1. What is “align”? Is it G1 or G2 (and why can’t I choose?)
  2. What do I need to do in order to have the “align cross section” not greyed out?

My goal is to have a mono rail with G2 for both the guide and the rail.

Hello - align keeps the tangency relationship of the cross section to the surface, whatever it is, constant along the edge.