This forum, on FB is absolutely one of the best sources for information and example photos for permanent, standing seam roofing. We rely on the translator service as almost nobody speaks english. Back in 2012, when I was studying folding and joinery techniques (with zero online resources in english) I used to pull the text one-by-one from PHP forums and paste into google translate. This is so much better as we can actually communicate; although it is somewhat broken.
This photo shows a really interesting valley concept, and the debate ensues… What is so unique and showy about this approach is that one whole side of the field had to be installed, and turned up. When the opposing side was installed: since the seams have to run in to and past the valley, it means they had to deform every field seam down, and lay them all over all the way up, so the pans would sit flush on the field. This is working blind. After that, they would have to close all of the connecting seams, and dress it down to fold the valley.
Trad Building 