PICTORIAL SYSTEMS
When we study how each projection system represents the same subject, we
can see how different pictorial effects result. We categorize these pictorial
systems into multiview drawings, paraline drawings, and perspective drawings.
Projection Systems
Orthographic Projection
Pictorial Systems
v"
Multiview Drawings
• Plans, sections, and elevations.
• The principal face in each view is oriented parallel to the picture plane.
Paraline Drawings
......... Isometrics: The three major axes make equal angles with the
picture plane.
Axonometric Projection
•D
imetrics: Two of the three major axes make equal angles with the
picture plane.
-· Trimetrics: The three major axes make different angles with the
picture plane.
Oblique Projection -
..... • Elevation obliques: A principal vertical face is oriented parallel to
the picture plane.
--t
......... P obliques: A principal horizontal face is oriented parallel to
lan
the picture plane.
Perspective Projection
These pictorial views are
available in most 3D CAD
and modeling programs.
The terminology, however,
may differ from what is
presented here.
Perspective Drawings
........ 1-point perspectives: One horizontal axis is perpendicular to the picture
plane, the other horizontal axis and the vertical axis are parallel w the
ith
picture plane.
w·
• 2-point perspectives: Both horizontal axes are oblique to the picture
plane, and the vertical axis remains parallel with the picture plane.
................. ·• 3-point perspectives: Both horizontal axes as well as the vertical axis
are oblique to the picture plane.
ARCHITECTURAl DRAWING SYSTEMS/ 25