An imaginary line(s) drawn from a point(s) in the audience to the first visual obstruction. Horizontal sightlines are often determined from the farthest offstage audience seat to the onstage edge of each leg, portal, torm or the proscenium itself. Vertical sightlines are often determined from the audience seat nearest the stage to the bottom edge of each border, teaser, valance, or the top of the proscenium itself.
