technical drawing chapter 1
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Technical Drawing CHAPTER 1. By : Aznita Abdullah. Why engineers use orthographic projection?. Engineers need to be able to explain and simplify complicated design ideas for others to understand. Why engineers use orthographic projection ?. - PowerPoint PPT PresentationTRANSCRIPT
Technical Drawing
CHAPTER 1
By:Aznita
Abdullah
Why engineers use orthographic projection?
Engineers need to be able to explain and simplify complicated design ideas for others to understand.
Why engineers use orthographic projection?
To show complicated 3 dimensional (3D) object in two dimension (2D)
ORTHOGRAPHIC PROJECTION• the object is looked at from three views at 90
degrees to each other.
ORTHOGRAPHIC PROJECTION – 3 VIEWS
1. Plan 2. Front View 3. Side View (or End View)
ORTHOGRAPHIC PROJECTION
Viewed in 2 ways:• 1st Angle Projection• 3rd Angle Projection.
1st Angle Projectionused mainly in USA
END VIEW
ISOMETRIC
FRONT VIEW
PLAN
1st Angle Projection Symbol
FRONT VIEW SIDE VIEWFRONT VIEW
SIDE VIEW
3rd Angle ProjectionUsed in UK and in most countries of the world
END VIEW
ISOMETRIC
FRONT VIEW
PLAN
FRONT VIEW
SIDE VIEW
3rd angle Projection Symbol
SIDE VIEW
FRONT VIEW
DIFFERENCE BETWEEN 1ST ANGLE AND 3RD ANGLE
1st Angle Projection 3rd Angle Projection
MODULE OBJECTIVESBy the end of this module the student will be able to:
1.1 Describe orthographic projection1.2 State why engineers use orthographic projection1.3 Compare 1st degree angle and 3rd degree angle
MODULE OBJECTIVES 1.4 By the end of this module the student will be able to:
Correctly sketch two-dimensional views from three dimensional drawings.
END VIEW
PLAN VIEW
FRONT VIEW
MODULE OBJECTIVES 1.5 By the end of this module the student will be able to:
Correctly identify and draw different types of line.