SPATIAL DEPTH CUES
We can enhance the perceived depth of aparaline drawing
by utilizing a hierarchy of line weights to distinguish
between spatial edges, planar corners, and surface lines.
_ _. Spatial edges are the boundaries of a form separated from
the background by some intervening space.
• Planar corners are the intersections of two or m planes
ore
t hat are visible t othe eye.
Surface lines are lines t h represent an abrupt contrast
at
incolor, t onal value, or m
ateria l; they do not represent a
.
change inform
• 3D-modeling programs treat lines as the continuous edges
of polygons. It may therefore be difficult to define this
hierarchy of line weights without first transferring the
graphic image to atwo-dimensional environment.
• To separate planes in space, to clarify their different
orientations, and especially to distinguish between the
horizontal and the vertical, we can use contrasting
textures and patterns.
PARALIN E DRAWINGS/ 81