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Angle of projection

Comeon swcalvert it is basic engineering graphics,we usually follow either the first angle projection or the third angle projection.In first angle projection object is in between viewer and the plane of projection whereasin third angle projection the plane of projection is in between object and the viewer.


But 2nd angle projection is used where there is space constraint.


We know that symbols for 1st angle projection and third angle projection are indicated in the title block of a drawing sheet.Similarly can we indicate the symbol for 2nd angle projection and 4th angle projection,in drawing sheet.
 
Hello calvert,


I forgot toadda note, in 2nd angle projection theprojections oftop and bottom views follow "1st angle projection convention"(i.e.the object is in between the plane of projection and the viewer) whereas all other views follow "3rd angle projection convention".
 
I know that the 2nd and 4th angle exists, I've just never used or seen them used in a drawing. We in America have used, for the most part, only 3rd angle projection, while most of the rest of the world uses 1st angle projection. I, for one, much prefer the view from outside the box looking in. In other words, unfold the box to see you views.


But back to your original question, I don't know of a symbol for either the 2nd or the 4th.
 
I've checked my ASME standard Y14.3M-1994 (not sure what the ISO standard is)and it tells me that there are two commonly used projections, 1st and 3rd. It does not show any symbols for 2nd and 4th.
 
Hello Chill,


I know we usually follow 1st or 3rd angle projection.


To give u the example u r asking, in a situation I don't have spcae in the drawingsheet to place a particular view in accordance with the angle of projection.Suppose I have to place top view ofthepart bellow front view (all otherviews following the 1st angle projection),I can only place it above the front view becauseof space constraint bellow the front view.Now look at the overall sheet,4th angle projection is followed in this case,right.


Bye...
 

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