1. Engineering Graphics 2018-19-I
Lecture 7
TA101A
Engineering Graphics I By
Dr. Mukesh Sharma
Professor
DEPARTMENT OF CIVIL ENGINEERING
INDIAN INSTITUTE OF TECHNOLOGY KANPUR
KANPUR , INDIA

2. Important All lines parallel to isometric axes – Isometric lines
All isometric lines are foreshortened equally (81/100)
All other non-isometric lines may or may not foreshorten
Foreshortening ratio of such lines may vary disproportionately
Projections of parallel lines are parallel.
All measurements can only be marked on isometric lines
30o
One Can draw isometric Figure with the help of Isometric box
Isometric
Axes A B A B
Isometric projection: foreshortened (81/100)
Isometric drawing: No foreshortening (100/100)

3. Isometric drawing = Isometric view

4. Front
Top
Right Side
Now start drawing
Isometric

5. Draw base as in previous isometric
Now draw the additional surface
Front
Top
Right Side
Smoothly join both circles
Identify hidden lines and erase

6. Front
Top
Right Side
Isometric

12. 900 900 300 600 900 Angles in isometric? Do not appear as true angles
See V-notch above

13. Do not measure angles; use isometric lengths to locate the pointb a C
Angles in isometric
Do not measure angles; use isometric lengths to locate the point

14. Curves in Isometric drawing
use isometric lengths to locate the points on the curve

15. Inclined Surface in Isometric

17. Dimensioning in Isometric drawing
Horizontal and Vertical Dimensions:
Both extension and dimension lines are in respective isomeric planes and
Numbers are perpendicular to the dimension line.

18. How do you know if your isometric drawing is correct?
It should yield exactly the same orthographic views from
those isometric drawing was built.

19. Oblique Projections Produces 3-D views
Process virtually opposite to isometric view
Do not look perpendicular through projection plane
Object is not rotated
Object remains with a major face parallel to projection plane
Now one looks the projection plane with an oblique angle
Axes of height and width remains at 90 degrees
Axis of depth can vary in angle, ø
What is specialty of oblique projection.
Isometric S R U
35 to 450
Oblique

20. A CABINET
B CAVALIER

21. Oblique drawing

22. What depth?

23. Object orientation for oblique
Place the object with the irregular outline or contour
parallel to the picture plane.