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Pictorial 3-dimensional representations
One-point
one vanishing point lines that are not vertical or horizontal
& converge to a single point in distance
Two-point or Three-point
two or three vanishing points with two points, vertical or
horizontal lines parallel, but not both With three-point, no lines
are parallel.
Isometric
Drawing shows corner of object, but parallel lines on object are
parallel in drawing. Shows three dimensions, but no vanishing
point.
ONE POINT
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TWO POINT
ISOMETRIC
ISOMETRIC DRAWING: IT IS A TYPE OF PICTORIAL PROJECTION IN WHICH
ALL THREE DIMENSIONS OF AN OBJECT ARE SHOWN IN ONE VIEW AND IF
REQUIRED, THEIR ACTUAL SIZES CAN BE MEASURED DIRECTLY FROM IT.
Orthographic view shows only two dimensions in any particular
view. This makes it difficult to interpret them and only
technically trained person can interpret the meaning of these
orthographic views. A non-technical person cannot imagine the shape
of the object from orthographic projections. Whereas, pictorial
projections can be easily understood even by persons without any
technical training because such views show all the three dimensions
of an object in the same view. But pictorial view does not show the
true shape and size of any principal surface of an object and it
does not show the hidden portions. Pictorial projections are easy
to imagine so these are normally used.
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Isometric Axes: The lines AB, AD and AE meeting at a point A and
making an angle of 120o with each other are termed isometric axes
Isometric Lines:
The lines parallel to the isometric axes are termed isometric
lines. The lines CD, CB etc are examples of isometric lines.
Non-isometric Lines:
The lines which are not parallel to isometric axes are termed
non-isometric lines. The BD is an example. Isometric Planes:
The planes representing the faces of the rectangular prism as
well as other planes parallel to these planes are termed isometric
planes.
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Isometric Plane and Non-isometric Plane:
Isometric Planes are marked as 1 and Non-isometric Planes are
marked as 2 Lecture 3 Tuesday, 04 March 2014 8
Isometric Drawing
Isometric Projection: Drawing prepared with isometric scale on
isometric axes
Isometric Drawing: Drawing prepared with ordinary scaleon
isometric axes
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Lecture 3 Tuesday, 04 March 2014 9
Steps:
Step 1
Isometric sketches begin with defining isometric axes, three
lines, one vertical and two drawn at 30 from the horizontal.
Lecture 3 Tuesday, 04 March 2014 10
Steps:
Step 2
Three lines of the isometric axes represent the three primary
dimensions of the object: width, height, and depth
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Lecture 3 Tuesday, 04 March 2014 11
Steps:
Step 3
Draw the font face of the isometric block.
Lecture 3 Tuesday, 04 March 2014 12
Steps:
Step 4
Draw the rest of the isometric block.
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Lecture 3 Tuesday, 04 March 2014 13
Steps:
Step 5
Add details to the block starting from the front face. Then add
details to the other faces.
Lecture 3 Tuesday, 04 March 2014 14
Steps:
Step 6
Darken all visible lines to complete the isometric sketch. (make
sure that construction lines are light)
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ORTHOGRAPHIC PROJECTIONS Orthographic Projection is a method of
representing a three dimensional object on
paper using several two dimensional views. It is the
international language of Engineers and Designers Orthographic
projections are drawings where the projectors, the observer or
station
point remain parallel to each other and perpendicular to the
plane of projection.
Orthographic Projection
Orthographic Projections are a collection of 2-D drawings that
work together to give an accurate overall representation of an
object.
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Six Principle Views
The 6 views of
projection include:
FRONT
RIGHT SIDE
TOP
BOTTOM
LEFT SIDE
REAR
Principle Views Front, Right Side
and Top are views that simply represented by rotating the
object
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Glass Box Most powerful technique to
understand orthographic projections Suspend the object with
transparent
strings inside a glass box Freeze the view from each
direction
(each of the six sides of the box) and unfold the box
Glass Box
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Glass Box
Glass Box
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Glass Box
Glass Box
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Glass Box