Model for Descriptive Geometry by A. Jullien - Intersection of Two Planes Parallel to a Line on the Ground (The x-axis)

Jullien, A. · ca 1880

Planes CDD’C’ and ABB’A’ are both parallel to the x-axis (crease in the card). They intersect in line (e, e’)-(f, f’) (wire) which is also parallel to the x-axis. The planes can be visualize by imagining both red strings extending left and right. Both projections of this intersection are shown as well as the rotation of it about the horizontal line perpendicular to the x-axis PA.