There are two main types of orthographic projections: first angle and third angle projection. The only difference between the two is the positioning of the plan, bottom, and side views relative to the front view. In first angle projection, the front view is in the center with the top view below and bottom view above, and the side views to the left and right. In third angle projection, the front view remains center but the top and bottom views are positioned differently relative to the side views. Orthographic projections use multiple 2D drawings to accurately represent an object from different angles.

1. Prepared By
Manthan Dhavne

2.  Orthographic Projections are a collection of
2-D drawings that work together to give an
accurate overall representation of an object.

4. Basically, there are 2 types of orthographic
projection. They are:
1) 1st angle projection
And
2)3rd angle projection
They are explained below.

5.  The one and only difference between 1st angle &
3rd angle projection is that only the
representation positions of plan (top view),
bottom view and side view.
 In 1st angle projection, the front view is in center,
top view is below front view, bottom view is
above front view, RHSV(right hand side view) is
to the left of front view and LHSV(left hand side
view) is to the right of front view.

6. Third-angle Projection
First-angle Projection
 First Angle
 Third Angle

7. General Guidelines
Pick a Front View that is most descriptive
of object
Normally the longest dimension is chosen
as the width (or depth)
Most common combination of views is to
use:
• Front, Top, and Side View

9. Place the object in a glass box
Freeze the view from each direction (each
of the six sides of the box) and unfold the
box

12. First angle
system
Third angle
system
PROJECTION SYMBOLS