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ORTHOGRAPHIC PROJECTION
ANGLES OF PROJECTION
The angle of projection depends on which of the four quadrants the object is placed on. The two principal orthographic projections are
- The first angle projection (English projection)
- The third angle projection (American projection)
The difference between these two is the method of the arrangement of the views.
THE FIRST ANGLE PROJECTION
The first angle projection is the projection in which the plan is located directly below the front elevation (view). What is seen from the left-hand side is drawn on the right hand side. What is seen from the right-hand side is drawn on the left hand-side. Hence, the plan is located directly below the front elevation (views)
| FRONT | SIDE |
| PLAN |
PROPERTIES OF FIRST ANGLE PROJECTION
The following are the properties of the first angle projection.
- The plan is always projected below the front view (elevation)
- The right-hand side view is shown on left hand side of the front view
- The left-hand side is shown on the right hand side of the front views.
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ClassHall Instructor
Halima Ahmadu
Melvyn Chukwu
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