Armada's rules for establishing firing arcs, firing ranges, and lines of sight are somewhat complicated. I've thrown a few diagrams together that (I hope) explain them better than the rulebook does. The full album is here: http://imgur.com/a/fs1ni (EDIT 4/20/2015: Combined images into one. Clarified range/LoS not arc-bound.) (EDIT 5/8/2015: Range measurements restricted to arc as per new errata.) (EDIT 12/20/2016: Blocked range check lines also block LoS and attacks, per