Elliptic Arch Notes : the first image lists some formulas for working with segmented arches.
Just for fun I tried making the working point (WP2) such that the slope of the ellipse at this point equals the slope of the rafter. A set of iterative calculations were needed to home in on this point (–117.43, 87.87).
Found a couple websites with pics of trusses with arches:
http://www.pacificpostbeam.com/Trusses-Hybrids_a.html http://www.rockportpostandbeam.com/timberframe.php
