This document discusses different types of technical drawing projections used to represent 3D objects in 2D drawings. It describes orthographic projections where projectors are perpendicular to the projection plane, resulting in front, top, and side views of an object. Axonometric projections show an object inclined toward the projection plane in a single view. Multiview projections use front, top, right side, etc. views. First angle and third angle projections determine the placement of views, with first angle being the European standard and third angle being used in America.

1. Orthographic Projections

2. Projections
Projections
Parallel/
Cylindrical
Perspective/
Conical
Oblique Orthographic One-Point Three-PointTwo-Point
Cabinet
Other
Cavalier
Multi-view
Axonometric
First-angle Fourth-angle Third-angle Second-angle
Isometric
(30°)
Di-metric Trimetric

3. Parallel Projections

4. Perspective Projections

5. Oblique Projections
• Projectors are parallel to each other but
not perpendicular to projection plane
• An oblique projection shows front and top
surfaces that include the three dimensions
of height, width, and depth.
• The front or principal surface of an
object (the surface toward the plane of
projection) is parallel to the plane of
projection.
• Effective in pictorially representing objects

6. Orthographic Projections
• 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 projections are further
subdivided into axonometric projections
and multi-view projections.
• Effective in technical representation of
objects

7. Axonometric
• The observer is at infinity & the projectors are parallel to each other and
perpendicular to the plane of projection. #
• A key feature of axonometric projections is that the object is inclined toward
the plane of projection showing all three surfaces in one view.
• The length of the lines, sizes of the angles, and proportions of the object varies
according to the amount of angle between the object and the plane of
projection.

8. Axonometric
The object is tilted
with all three
coordinate axes are
visible in any one
view
(PP projection plane)

9. Orthographic (Orthogonal)
The object is at rest
and two coordinate
axes are visible in
any one view
(PP projection plane)

10. Multiview Projections

11. Multiview Projections
• Front surfaces of object is parallel to plane of
projection
• Projectors or line of sights are perpendicular to
projection plane
• Projectors are parallel to each other and
originate from any point on object

12. The six views

13. Angles
• First angle projection – European System
• Third angle projection – American System

14. First Angle Projection

15. First Angle Projection 1
How to draw plan and elevation?

16. First Angle Projection 2
How to draw end view?

17. First Angle Projection 3
Points to remember:
• The ‘front view’ (or elevation) is the view
with maximum information.
•The ‘plan’ is below the ‘elevation’ (in
projection).
•The ‘end view’ is placed on the right if
viewed from left side of object and on the
left if viewed from right side.
•‘End view’ and plan face inwards from
‘elevation’.

18. Third Angle Projection

19. Third Angle Projection 1
How to draw plan and elevation?
In 3rd angle projection planes are transparent
and objects are viewed through them

20. Third Angle Projection 2
How to draw end view?

21. Third Angle Projection 3
Points to remember:
• The ‘front view’ (or elevation) is the view
with maximum information.
•The ‘plan’ is above the ‘elevation’ (in
projection).
•The ‘end view’ is placed on the right if
viewed from right side of object and on the
left if viewed from left side.
•‘End view’ and plan face outwards from
‘elevation’.

22. STAY curious
MADHUR MAHAJAN