UNIT 4

Orthographic Projections

4.1 Conversion of pictorial view into orthographic views

Orthographic Projections is a technical drawing in which different views of an object are projected on different reference planes observing perpendicular to respective reference plane.

Different Reference planes are

• Horizontal Plane (HP)
• Vertical Plane (VP)
• Side or Profile Plane (PP)

Different views are

• Front View (FV) – Projected on VP
• Top View (TV) – Projected on HP
• Side View (SV) – Projected on PP

NOTATIONS

Following notations should be followed while naming

Different views in orthographic projections.

Same system of notations should be followed in case numbers, like 1, 2, 3 – are used

Types of views

Orthographic views

Views arrangement

Projection symbols

Methods of Orthogonal Projection

1. Natural Method: Revolve the object with respect to observer
2. Glass box method: The observer moves around the object

2.     Glass box : Revolution of the planes of projection

Relative orientation of views

Summary : Problem solving steps

Steps for Orthographic Views

• Select the necessary views
• Layout the selected views on a drawing sheet.
• Complete each selected views.
• Complete the dimensions and notes.