08-05-2012, 03:51 PM
Basics of Orthographic
13723_orthographic projection.ppt (Size: 3.62 MB / Downloads: 45)
Orthographic Projections
Drawing is the one of the language of communicating our views and ideas in the form of picture.
As like the all language this also have its grammar and own vocabulary .
Lines are the words for this language and set of lines forms the sentence which conveys the our idea .
So for that it is important to study the different types of lines used in drawing.
In engineering drawing, the word ‘projection’ means an image or the act of obtaining the image of an object.
ORTHOGRAPHIC VIEWS
Front View When the observer looks at the object from the front, the view obtained is called the front view (FV) or Elevation. FV is seen on the VP.
Top View When the observer looks at the object from above, the view obtained is called top view (TV) or plan. TV is seen on the HP.
Side Views When the observer looks at the object from side, i.e., from his left-hand side or right hand side, the view obtained is called side view (SV). SV is seen on the PP.
Left-Hand Side View When the observer views the object from his left-hand side, the view obtained is called left-hand side view (LHSV).
Right Hand Side View When the observer views the object from his right-hand side, the view obtained is called as right-hand side view (RHSV).
First-angle Projection Method
In first-angle projection, an object is placed in the first quadrant, i.e., above the HP and in front of the VP. (shown in NEXT fig.)
The object lies in between the observer and the plane of projection.
The plane of projection is assumed to be non transparent and views drawn on it.
Front view is above the reference axis and top view lies below the reference axis exactly bellow the front view.
Right hand side view is drawn to left of front view and Left hand side view is drawn to the right of front view.
First angel projection symbol: