Transcript Drawing Construction

Name of the course :Drawing
construction
Course code :HED 129
Credit hours :3hours
Prepared by Eng. Nadir Abd
alrazig siddig
Multiview Drawings
Multiview drawings can be visualized by
what is commonly called the glass box theory.
In this process, a three-dimensional object is
imagined to be surrounded by a clear glass box
(Figure 3-1). If the viewer looks along the
perpendicular through any plane on the glass
box, the object can be imagined to be a flat,
two-dimensional image on that particular
glass pane. The object can be viewed
from above (called a plan view) or the side
(called an elevation view). In turn, if these
images are drawn separately, the viewer
reverses the process and projects (by
imagining) the multiviews onto a whole threedimensional object.
Orthographic Projections
The word orthographic refers to the
projection system that is used to derive
multiview drawings based on the glass box
model. Drawings that appear on a surface are
the view a person sees on the transparent
viewing plane that is positioned perpendicular
to the viewer’s line of sight and the object. In
the orthographic system, the object is placed
in a series of positions (plan or elevation)
relative to the viewing plane.
Single-view Drawings
Single-view drawings attempt to picture an
object or space as we normally see it in reality
with all three dimensions appearing
simultaneously. They present relationships of
objects, space, and materials in a realistic or
photographic-looking manner. Singleview
• drawings can be either paraline or perspective
views. In paraline drawings, lines are drawn
parallel to one another, and object features
retain this relationship as they appear to
recede in the distance (Figure 3-2).
Paraline Drawings
• Paralines are usually faster and easier to
develop than perspectives, as receding
horizontal lines can be drawn with instruments,
without calculating depths or drawing lines to a
common vanishing point as is necessary in
perspective drawings. However, when using
computer-aided design (CAD), the speed of the
rendering programs will govern which of these
is produced the quickest. Paraline drawings are
categorized according to the projection method
used to develop them, and can be subdivided
into two distinct types, axonometric and
oblique (Figure 3-3).
Axonometric Projections
•
Some interior designers refer to all
paralines
as
axonometrics;
however,
axonometric drawings are technically just one
form of paraline drawing. Axonometric means
“measurable along the axes.” Axonometric
drawings include three axes that relate to
width, depth, and height. Each line drawn
parallel to these axes is drawn at an exact
scale with the true length of the object
depicted. The axonometric projection
system consists of three primary views:
isometric, dimetric, and trimetric. These views
are distinguished by the degree of variation
visible of the principal faces of the object. In
the isometric view, all faces represent true
scales.
Oblique Projections
• Oblique projections are popular among
interior designers. Although there are several
types of oblique drawings, the plan oblique
and elevation oblique are the most commonly
used. In these drawings, the floor plan or
elevation serves as the true face on the
picture plane, and parallel lines are projected
vertically or horizontally at an angle other
than 90 degrees from this face. The viewer’s
lines of sight are parallel, but are not at right
angles with the viewing plane (Figure 3-4).
Perspective Drawings
A perspective drawings is a type of singleview drawing that is more realistic-looking than
an oblique or axonometric drawing. In a
perspective drawing, objects appear to
diminish in size as they recede into the
distance, and lines that are parallel in the
actual object appear to converge at some
distant point on the horizon (termed the
vanishing point). Perspectives are used
primarily as presentation drawings to portray a
finished object, building, or interior space
(Figure 3-5). Perspectives most closely
duplicate what our eye or a camera sees.
One-Point Perspectives
Of the three types of perspective, the onepoint is perhaps the easiest to understand and
construct. In one-point perspectives, receding
lines or sides of an object appear to vanish to a
single point on the horizon
Two-Point Perspective
• The two-point perspective is one of the most
widely used of the three types, as it portrays
the most realistic view for the observer
• (Figure 3-7).
Three-Point Perspective
Three-point perspectives are generally
drawn with the viewer at a distance above the
horizon (bird’s-eye view) or below the horizon
(worm’s-eye
view).
The
three-point
perspective is used mostly for very tall
buildings and is rarely used in interior spaces,
unless they are multistoried. Three-point
perspectives are more complicated than the
former two types, as a third vanishing point is
introduced, which precludes all parallel lines.
CW No 2
Draw the chair in isometric by suitable dimension