Transcript Les projections orthogonales

Multi-view orthographic
projections
Multi-view orthographic
projections
Multi-view orthographic
projections are a part of parallel
projections. In this type of
drawing, the observer is
considered to be at an infinite
distance. The projecting lines are
thus parallel to one another.
These projections are also
orthographic since the projecting
lines are perpendicular to the
projection plane.
Multi-view orthographic
projections
Another distinguishing element
in multi-view projections is that
one of the faces of the object to
be drawn is placed parallel to the
projection plane.
The observer can only see
one side at a time.
That is why, in most cases, one
must draw several views of the
object to portray it completely.
Multi-view orthographic
projections
Hauteur
In technical drawing, the views are flat figures (two
dimensions) that we see from directly in front of each
object.
Largeur
Multi-view orthographic
projections
In the type of projections
used in North America, we
imagine the object being
drawn in the center of a
transparent box.
The different views of the
object are projected onto
the sides of this box.
Multi-view orthographic
projections
One of these views is
designated as the front
view of the object.
We usually choose the
face that best portrays the
object.
The choice of the front
view determines the
placement of the other
views.
Multi-view orthographic
projections
The projection box and its
six views are spread in
such a way as to place all
the views on the same
plane.
The other views pivot
around the front view.
TOP VIEW
REAR VIEW
LEFT SIDE VIEW
FRONT VIEW
BOTTOM VIEW
RIGHT SIDE VIEW
Multi-view orthographic
projections
Among the six possible
views, we will choose to
portray those necessary
to the description of the
shape of the object.
TOP VIEW
Three views are usually
enough to portray an
object. Many simple
VUErequire
DE GAUCHE
VUE ARRIÈRE
objects
may only
one or two views.
FRONT VIEW
BOTTOM VIEW
RIGHT SIDE VIEW
Multi-view orthographic
projections
TOP VIEW
Here is the usual representation of
views in multi-view orthographic
projections.
This type of drawing is used in
technology because it allows
description without deforming the
faces of objects.
FRONT VIEW
RIGHT SIDE VIEW
Multi-view orthographic
projections
LENGTHS
W
I
D
T
H
S
One view shows only two
dimensions.
On the front view are height and
length, on the top view, width and
length and on the side view, width
and height.
H
E
I
G
H
T
S
Multi-view orthographic
projections
LENGTHS
W
I
D
T
H
S
TOP
VIEW
LENGTH
WIDTH
FRONT
VIEW
LENGTH
HEIGHT
HEIGHT
WIDTH
RIGHT SIDE
VIEW
H
E
I
G
H
T
S
Multi-view orthographic
projections
TOP VIEW
This drawing technique
is also quick for objects,
because it allows
dimensions to be
projected from one view
to the other.
H
E
I
G
H
T
S
FRONT VIEW
RIGHT SIDE VIEW
Multi-view orthographic
projections
LENGTHS
Multi-view orthographic
projections
TOP VIEW
W
I
D
T
H
S
The 45˚ line allows the
45º
FRONT VIEW
widths of the top view
to be carried over to
the right side view or
vice versa.
RIGHT SIDE VIEW
Multi-view orthographic
projections
TOP VIEW
45º
FRONT VIEW
The 45˚ line allows the
widths of the top view
to be carried over to
the right side view or
vice versa.
RIGHT SIDE VIEW
Bibliography
GIESECKE, Frederick E., MITCHELL, Alva, SPENCER, Henry
Cecil, HILL, Ivan Leroy, GYGDON, John Thomas et NGUYEN,
Dinh N. « Dessin technique », Montréal, Éditions du Renouveau
Pédagogique inc., 1982, 769 p.
JENSEN, C.H. « Dessin industriel », Montréal, McGraw-Hill, 1972,
752 p.
STIRLING, Norman. « Éléments de dessin industriel », Montréal,
HRW, 1979, 372 p.