This document discusses orthographic projections in engineering graphics. It explains that orthographic projections show the front, top, and side views of an object by observing it from different angles. These multiple views provide an accurate way to represent 3D objects on a 2D surface. The document also describes first and third angle projections, and how orthographic views show length, width, or height by hiding the other dimensions from view. It provides examples of how orthographic views are represented on drawings.
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Eg unit 1 orthographic projection
1. GE 8152 - ENGINEERING GRAPHICS
Dr.R.Ganesamoorthy.
Professor / Mechanical Engineering.
Chennai Institute of Technology.
GE8152- ENGINEERING GRAPHICS UNIT-1 ORTHOGRAPHIC PROJECTION
UNIT-1 ORTHOGRAPHIC PROJECTION
2. GE8152- ENGINEERING GRAPHICS UNIT-1 ORTHOGRAPHIC PROJECTION
In orthographic projections, the principle views Front view, Top view, & Side views
of an object are drawn by the direct observation.
These views are drawn from the pictorial view of an object. The pictorial view is a
three dimensional representation.
By observing pictorial view, it is very easy to visualize the shape when the object is
viewed from front, top & sides.
Multi-view drawings provide the most accurate description of 3D objects and
structures for engineering, manufacturing, and construction requirements
3. GE8152- ENGINEERING GRAPHICS UNIT-1 ORTHOGRAPHIC PROJECTION
In engineering, there are two systems of projection:
First Angle Projection Europe, Asia and former European colonies in Africa and
parts of Australia
Third Angle Projection Used in the USA and Canada, in Africa where American
development is taking place and parts of Australia
6. GE8152- ENGINEERING GRAPHICS UNIT-1 ORTHOGRAPHIC PROJECTION
ORTHOGRAPHIC PROJECTIONS :
Views What Seen
Front view Length and Height(width not consider)
Top view Length and width(Height not consider)
Side view Height and width(Length not consider)