```PERSPECTIVE DRAWING
WAWERU HANNAH NYAKIO
B02/53847/2012
PERSPECTIVE DRAWING

Perspective drawing is a drawing technique used to illustrate dimension
through a flat surface. It is an approximate representation of a threedimensional object on a flat surface as it is seen by the eye.

The two most characteristic features of perspective are that objects are
drawn:
I.
Smaller as their distance from the observer increases
II.
Foreshortened: the size of an object's dimensions along the line of sight
are relatively shorter than dimensions across the line of sight.

There are many forms used under perspective drawing such as, one
perspective, two-point perspective, three-point perspective, four-point
perspective, five-point perspective, bird’s eye view, worm’s eye view and
others.
FORESHORTENING

Foreshortening is the visual effect or optical illusion that causes an object or
distance to appear shorter than it actually is because it is angled toward the
viewer.
 Additionally, an object is often not scaled evenly: a circle often appears as an
ellipse and a square can appear as a trapezoid.
 Although foreshortening is an important element in art where visual
perspective is being depicted, foreshortening occurs in other types of twodimensional representations of three-dimensional scenes.
 Some other types where foreshortening can occur include:
I. Oblique parallel projection drawings. Two different projections of a stack of
two cubes, illustrating oblique parallel projection foreshortening ("A") and
perspective foreshortening ("B")
II. Epimetheus (lower left) and Janus (right). The two moons appear close
because of foreshortening; in reality, Janus is about 40,000 km farther from
the observer than Epimetheus.
(i)
(ii)
ONE POINT
A linear perspective in which all parallel
lines meet at a single point on the
horizon.
Therefore one establishes the flat side
of the object, then makes all the
receding lines to meet at a single
vanishing point.
TWO POINT
A graphical technique in which a threedimensional object is represented in twodimensions and in which parallel lines in
two of its dimensions are shown to
converge towards two vanishing points.
THREE-POINT
Linear perspective in which parallel
lines along the width of an object meet
at two separate points on the horizon
and vertical lines on the object meet at
a point on the perpendicular bisector of
the horizon line.
FOUR POINT





Four-point perspective, also called infinite-point perspective, is the
curvilinear variant of two-point perspective.
As the result when made into an infinite point version), a four point
perspective image becomes a panorama that can go to a 360 degree view
and beyond – when going beyond the 360 degree view the artist might
depict an "impossible" room as the artist might depict something new when
it's supposed to show part of what already exists within those 360 degrees.
This elongated frame can be used both horizontally and vertically and when
used vertically can be described as an image that depicts both a worm's- and
bird's-eye view of a scene at the same time.
Like all other foreshortened variants of perspective (respectively one- to sixpoint perspective), it starts off with a horizon line, followed by four equally
spaced vanishing points to delineate four vertical lines.
The vanishing points made to create the curvilinear orthogonals are thus
made ad hoc on the four vertical lines placed on the opposite side of the
horizon line. The only dimension not foreshortened in this type of
perspective is the rectilinear and parallel lines perpendicular to the horizon
line – similar to the vertical lines used in two-point perspective.
FIVE-POINT
A curvilinear perspective with its
vanishing points are mapped into
a circle such that four vanishing
points are at the cardinal
headings i.e. n, w, s, e and one at
the circle origin.
ZERO POINT

Since vanishing points exist only when parallel lines are present in the scene,
a perspective with no vanishing points ("zero-point" perspective) occurs if
the viewer is observing a non-linear scene.

The most common example of a nonlinear scene is a natural scene (e.g., a
mountain range) which frequently does not contain any parallel lines.

A perspective without vanishing points can still create a sense of depth.
METHODS OF CONSTRUCTION

Several methods of constructing perspectives exist, including:

Freehand sketching (common in art)

Graphically constructing (once common in architecture)

Using a perspective grid

Computing a perspective transform (common in 3D computer
applications)

Mimicry using tools such as a proportional divider (sometimes called a
(variscaler)
LIMITATIONS
i.
Only three sides of a component are shown.
ii.
No feature is a true proportion. They are not drawn to a constant scale.
iii.
Sectioned perspective drawings are often confusing.
iv.
Sometimes a hidden outline is shown which can be confusing.
v.
Dimensions are often difficult to show.
It is due to these disadvantages that engineering drawings are
rarely drawn in perspective projection.
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