View
250
Download
3
Category
Preview:
Citation preview
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 1/50
Acknowledg
• Main contributors of Engineering Drawing lecture slid
and modification as well as lab/tutorial questions prepara
– Prof. S.C. Mishra, IIT Guwahati
– . . . . ,– Prof. P.S. Robi, IIT Guwahati
– Dr. Subhasis Dutta, IIT Guwahati
– Dr. Sujit Dash, IIT Guwahati
• This is to acknowledge that some slides are downloaded
• Thanks to Dr. Rajib Bhattacharjya and Dr. Arindam Dey
the final lecture slides in internet.• Thanks to all other colleagues and academic staff memb
I missed to mention in this page.
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 2/50
ME 111: Engineering Dra
Date: 17/10/2011
Lecture 15 Isometric Projections
Indian Institute of Technology GuwahGuwahati – 781039
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 3/50
Announc
• Makeup lab class (Lab 12):
– Inform the respective Tutor one week be
during lab 11, about the lab (only one) yo
.– Give Your Name, Roll No., Group No. a
• End semester examination:
– 19th Nov. 2011 (Saturday), and– 20th Nov. 2011 (Sunday)
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 4/50
Th
pr
prm
lin
pe
th
th
in
ob
ab
prpi
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 5/50
Axonometric projection - is a parallel projecused to create a pictorial drawing of an object object on an axis relative to a projection or pic
The differences between a multiview drawing and drawing are that, in a multiview, only two dimensionsvisible in each view and more than one view is requirobject; whereas, in an axonometric drawing, the oabout an axis to display all three dimensions, and o
required.
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 6/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 7/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 8/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 9/50
Isometric axes can be positioned in a nways to create different views of the sa
Figure A is a regularisometric, in which theviewpoint is looking downon the top of the object.
In a regular isometric, theaxes at 30 to the horizontalare drawn upward from the
For the reversed axisisometric, the viewpoint islooking up on the bottomof the object, and the 30axes are drawn downward
from the horizontal.
For the long axis isometric, the viewpoint is looking f
or from the left of the object, and one axis is drawn
horizontal.
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 10/50
Isometric drawings are almost always prefisometric projection for engineering because they are easier to produce.
ISOMETRIC PROJECTION and ISOMETRIC D
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 11/50
An isometric drawing is an axonometric pictofor which the angle between each axis equals
scale used is full scale.
Size comparison of Isometric Drawing and True Isome
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 12/50
Isometric Axonometric ProjectAn isometric projection is a true representation of the isan object.
An isometric view of an object is created by rotating about a vertical axis, then tilting the object (see figure -cube) forward until the body diagonal (AB) appears asfront view
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 13/50
The angle the cube is tilted forward is 35 16’. The 3 at A, B form equal angles of 120 and are called the is
Each edge of the cube is parallel to one of the isometr
Line parallel to one of the legs of the isometric axis is anPlanes of the cube faces & all planes parallel to them are
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 14/50
The forward tilt of the cube causes the edges and planesbecome shortened as it is projected onto the picture pla
The lengths of the projected lines are equal to the cosine0.81647 times the true length. In other words, the projecapproximately 82% of the true lengths.
A drawing produced using a scaleof 0.816 is called an isometric projection and is a true
.
However, if the drawing is producedusing full scale, it is called anisometric drawing , which is thesame proportion as an isometric
projection, but is larger by a factorof 1.23 to 1.
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 15/50
Isometric scale is produced by positioning a regular scthe horizontal and projecting lines vertically to a 30 li
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 16/50
In an isometric drawing, true length distances can on
along isometric lines, that is, lines that run paralle
isometric axes. Any line that does not run parallel to an
called a non-isometric line.
Non-isometric lines
include inclined and
not be measured
directly. Instead they
must be created by
locating two end points.
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 17/50
Figure A is an isometric
drawing of a cube. The three
faces of the isometric cube are
isometric planes, because they
are parallel to the isometric
surfaces formed by any two
ad acent isometric axes.
Figure A: Isometri
Planes that are not parallel to
any isometric plane are called
non-isometric planes (Figure B)
Figure B: Non-is
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 18/50
In isometric drawings,
hidden lines are omittedunless they are absolutelynecessary to completelydescribe the object. Mostisometric drawings will nothave hidden lines.
Standards for Hidden Lines, Center Lines an
To avoid using hidden lines,choose the most descriptiveviewpoint.
However, if an isometric
viewpoint cannot be foundthat clearly depicts all themajor features, hidden linesmay be used.
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 19/50
Centerlines are drawn only for showing symdimensioning. Normally, centerlines are not sh
many isometric drawings are used to commutechnical people and not for engineering purpose
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 20/50
As per the Standards:
Dimension lines,
extension lines, and linesbeing dimensioned shall
lie in the same plane.
All dimensions and notes
should be unidirectional,
rea ng rom e o omof the drawing upwardand should be located
outside the viewwhenever possible. The
texts is read from the
bottom, using horizontalguidelines.
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 21/50
ISOMETRIC VIEWS OF STANDARD SHAPES
Square
Consider a square ABCD with a 30 mm side shown in Fig
lies in the vertical plane, it will appear as a rhombus with a
isometric view as shown in Fig. (a) or (b), depending on
i.e., right-hand vertical face or left-hand vertical face. If th
the horizontal plane (like the top face of a cube), it wi
Fig.(c). The sides AB and AD , both, are inclined to t
reference line at 30°.
Taken from Dhananjay A Jolhe, Engg. Drawing, MGH
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 22/50
Rectangle
A rectangle appears as a parallelogram in isometric
versions are possible depending on the orientrectangle, i.e., right-hand vertical face, left-hand ve
horizontal face.
Taken from Dhananjay A Jolhe, Engg. Drawing, MGH
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 23/50
Triangle
A triangle of any type can be easily obtained in iso
explained below. First enclose the triangle in rectangle
parallelogram ABCD for the rectangle as shown in Fig.
Then locate point 1 in the parallelogram such th
parallelogram is equal to C –1 in the rectangle. A –B –1
isometric view of the triangle.
Taken from Dhananjay A Jolhe, Engg. Drawing, MGH
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 24/50
Pentagon
Enclose the given pentagon in a rectangle and obtain the
as in Fig. 18.9(a) or (b) or (c). Locate points 1, 2, 3, 4
rectangle and mark them on the parallelogram. The distan
C –3, C –4 and D –5 in isometric drawing are same as the
distances on the pentagon enclosed in the rectangle.
Taken from Dhananjay A Jolhe, Engg. Drawing, MGH
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 25/50
Circle
The isometric view or isometric projection of a circle is
obtained by using four-centre method explained below.
Four-Centre Method : First, enclose the given circle intoDraw rhombus ABCD as an isometric view of the square.
corners of the rhombus, i.e., A and C . Obtain midpoints 3 a
and AD respectively. Locate points 1 and 2 at the intersectio
and B –4 respectively. Now with 1 as a centre and radius 1
arc 3–5. Draw another arc 4–6 with same radius but 2 as a
a centre and radius B –3, draw an arc 3–4. Draw another a
ra us u w as a cen re.
Taken from Dhananjay A Jolhe, Engg. Drawing, MGH
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 26/50
Any irregular Shape
Any irregular shape 1–2–3–4–5–6–7 can be drawn in isom
follows: The figure is enclosed in a rectangle first. The pa
obtained in isometric for the rectangle as shown. The isol
C –3, E –3, G –4, F –4, H –5, H –6 and A –7 has the same length
shape, e.g., B –2 in isometric = B –2 in irregular shape.
Taken from Dhananjay A Jolhe, Engg. Drawing, MGH
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 27/50
The Boxing-in Method
The four basic steps for creating an isometric dra
Determine the isometric viewpoint that clearly d
features of the object, then draw the isometric ax
will produce that view-point.
Isometric views for solids
, height (H), and depth (D) of the object, such that
will be totally enclosed in a box.
Locate details on the isometric planes.
Darken all visible lines, and eliminate hidden line
absolutely necessary to describe the object.
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 28/50
STEPS
1. Positioning object.
2. Select isometric axis.
3. Sketch enclosing box.
4. Add details.
Sketch from an actual object
5. Darken visible lines.
Note In isometric sketch/drawing), hidden lines are omitted u
absolutely necessary to completely describe the object.Sketch fr
object
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 29/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 30/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 31/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 32/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 33/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 34/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 35/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 36/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 37/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 38/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 39/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 40/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 41/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 42/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 43/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 44/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 45/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 46/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 47/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 48/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 49/50
8/10/2019 Lecture15 Isometric Projection-pkghosh
http://slidepdf.com/reader/full/lecture15-isometric-projection-pkghosh 50/50
Recommended