This document contains only Introduction and some portion of Orthographic projection

1. Engineering Drawing
Mettu university
Department of Mechanical Engineering
A.Y.- 2022
Prepared by: Lamesa B.

2. What is engineering drawing?
An engineering drawing, a type
of technical drawing, which is
used to fully and clearly define
requirements for engineered
items with scales.
Engineering drawing example
Typically, the purpose of an
engineering drawing is to clearly
and accurately capture all
geometric features of
a product or component so that
a manufacturer or engineer can
produce the required item
Prepared by: Lamesa B.

3. Importance of Engineering
Drawings
• Helps as a reference to workers, technicians or
architects.
• Easy to understand : Since a picture is easiest method
than thousand words, a technical drawing is a much
more effective tool for engineers than a written plan.
• Engineering drawings is used in all engineering fields,
including, but not limited to, civil engineering, electrical
engineering, mechanical engineering and architecture.
• Universal language for engineers
Prepared by: Lamesa B.

4. Elements of engineering
drawing
Engineering drawing are made up of graphics language and word language
Prepared by: Lamesa B.

5. Drawing can be done:-
Prepared by: Lamesa B.
Object
Front view
Top view

6. Instruments are used to draw straight lines, circles, and curves concisely and
accurately. Thus, the drawings are usually made to scale
Prepared by: Lamesa B.

7. The drawings are usually made by commercial software such as AutoCAD, solid
works, Ansys, Catia, Free cad, abacus, and etc.
Example
Prepared by: Lamesa B.

8. Application Area
Prepared by: Lamesa B.

9. Prepared by: Lamesa B.

10. Prepared by: Lamesa B.

11. List of tools required for drawing
during practical session
NOTE:
➢ Students without
Engineering
Drawing Box will
not be allowed to
attend the
practical session
Prepared by: Lamesa B.

12. Prepared by: Lamesa B.

13. Set-square
Prepared by: Lamesa B.

14. Prepared by: Lamesa B.

15. Prepared by: Lamesa B.

16. Sketch Vs Engineering drawing
• Sketch: made without drafting tools... Just pencil and paper. Scale is
approximate, not accurate, but the sketch should still look like the
object.
• Engineering Drawing:
✓ Made with drafting tools... Ruler, set squares, protractor and compass.
Scale should be accurate and the drawing carefully made.
✓ contains all the necessary information, required for the
construction/fabrication of the object, like
➢ actual shape,
➢ accurate sizes,
➢ manufacturing methods,
➢ materials to be used etc.,
Prepared by: Lamesa B.

17. Theory of Projection
Prepared by: Lamesa B.
• The projection theory is used
to graphically represent 3-D
objects on 2-D media (paper,
computer screen).
❖ The projection theory is
based on two variables:
1) Line of sight
2) Plane of projection (image
plane or picture plane)

18. Line of sight:
✓ Is an imaginary ray of light between
an observer’s eye and an object
❖ There are 2 types of LOS :
parallel and converge
Prepared by: Lamesa B.

19. Prepared by: Lamesa B.
✓ Is an imaginary flat plane on
which the image is created
Plane of projection
❖ The image is produced by connecting
the points where the LOS pierce the
projection plane.

20. Principal Plane
❖ Is the plane on which the principal view of an
object is represented/drawn
There are three principal planes:
▪ Vertical plane/frontal plane: shows the width and height
dimension/F.V/
▪ Horizontal plane: shows the width and depth dimension/T.V/
▪ Profile plane: shows the depth and height dimension/S.V/
Prepared by: Lamesa B.

21. Prepared by: Lamesa B.

22. Projection
Prepared by: Lamesa B.

23. Prepared by: Lamesa B.

24. Parallel Vs perspective
Projection
➢The distance between the object
and the observer is infinite.
➢Viewed from multiple point.
➢The distance between the object
and the observer is finite
➢Viewed from a single point
Prepared by: Lamesa B.

25. Orthographic projection
➢ Different Reference
planes are
• VP
• HP
• PP
Prepared by: Lamesa B.
Orthographic projection is a parallel projection technique in which
different views of an object are projected on different reference planes
observing perpendicular to respective reference plane.
➢ Different views are
• FV w/c is projected VP
• TV Different views are HP
• SV Different views are PP

26. Cont.…..
Prepared by: Lamesa B.

27. Cont.…..
Prepared by: Lamesa B.

28. Cont.…..
Prepared by: Lamesa B.

29. Cont.…..
Prepared by: Lamesa B.

30. FV
TV
Draw Three Views Of This Object
By First Angle Projection Method
Prepared by: Lamesa B.

31. Prepared by: Lamesa B.