Rafter, framing & T-bevel are useful types of this "geometric" tool
sbebuilders.com/tools .... After trying this type of developmental geometry for a 12
:12 pitch I ... Knowing how to mark the side cut on the board isn't going to help ... 
copy of the drawing on Page #1 of the CA Geometric Roof Framing... [DOC] [TLE] Cutting hip/valley rafters: can someone clarify ?