Selected Bibliography Architectural Graphics | Page 152

SHADE & SHADOWS IU)(?!: VJS:W OF WALl- c J;U:.VAiLON • The shadow of a straight line is t heintersection of its shadow plane with the surface receiving the shadow. The hypotenuse of the triangular shadow plane establishes the direction of the light rays, and its base describes their bearing. 146 I ARCHITECTURAL GRAPHICS ' ~'" ~. The shadow of a stra ight lineon a flat surface isthe linethat connects the shadows of its end points. If the line intersects the surface, ' '. its shadow must beg inat that juncture. ~ Ashadow line changes direction where it crosses a corner, edge, or other break in the continuity of a surface. ''-....._, Astraight line casts onto a parallel planea shadow that is parallel to itself This isalso true when the line is parallel t othe straight lines in a curved surface receiving the shadow.