It simply and safely and quickly helps to determine roof angles and areas for designing, or estimating or figuring the volume of a roof area on a house without actually having to get ON the roof.
Step 1: Print it out
I have use various thickness papers and double some up with double sided tape and then laminated it with scotch (type) tape.
Success is about the stiffness of the backing material and the hinges or pivot points. Grommets worked very well for me on thinner stock, but I could not find grommets that worked with thicker poster board.
Step 2: Cut it out
There are 2 presented on the PDF one with rounded corners, one without corners.
Step 3: Attach printout to stiffer backing material
Step 4: Holes for pivot points and fasteners
Grommets from paper / fabric crafting work well but require thiner paper / cardboard / plastic stock.
Rivets from the hardware store work well but purchase a extra and test first.
Screw post binders from the hardware store are more expensive but easier to use.