MULTIVIEW DRAWINGS
Orthographic Projection
Orthographic projection represents a threedimensional form or construction by projecting lines
perpendicular to the picture plane.
Projectors are both parallel to each other and
perpendicular to the picture plane.
Major faces orfacets of the subject are typically
oriented parallel with the picture plane. Parallel
projectors therefore represent these major faces in
their true size, shape, and proportions. This is the
greatest advantage of using orthographic
projections-to be able to describe facets of a
form parallelto the picture plane without
foreshortening.
Ambiguity of depth is inherent in any orthographic
projection, as the third dimension is flattened onto
the picture plane.
Lines that are perpendicular to the picture plane
areprojected as points.
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Planes that are perpendicular to the picture plane
are projected as lines.
Curved surfaces and those that are not parallel to
the picture plane are foreshortened.
• Note that the pro
jected size of an element remains
constant regardless of how far forward or back it is
from the picture plane.
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I ARCHITECTURAL GRAPHICS