Projection of Points

Sample Problem 1:
Point A is 30mm above HP and 45mm infront of VP. Draw its Front View and Top view.

Steps for Projection of Points 

1. Look at the pictorial view fig (i). Point A lies in the first quadrant.
2. To obtain the Front View a’, look at the Pictorial View from the front.
   Point A is 30mm above HP. Aa’ is the projector perpendicular to the VP. Hence a’ is the Front View of the Point A and it is 30mm above the XY line.
3. To Obtain the Top View a, look at the pictorial View from top.
   Point A is 45mm infront of VP. Aa is the projector perpendicular to the HP.
   Hence a is the Top view of the point A and it is 45mm infront of XY.
4. To convert Projections a’ and a from pictorial view into Othographic Projections.
   > Rotate HP about XY line through 90º in the CW direction as shown in fig (i).
   >After Rotation, first quadrant is opened out and the HP occupies the position (dashed line) vertically below the VP.
   >Also, the point a, on HP will trace a quadrant of a circle with O as center and oa as radius. Now , a occupies the position just below O.
   > See fig (ii) Line Joining a’ and a, called Projector, is perpendicular to XY.How to draw the orthographic projections on the drawing Sheet: fig(iii)
   
5. Front View: See fig(iii). Draw the XY line and draw the Projector at any point on it.Mark the Front View a’ 30mm above XY on the projector.
6. Top View: On the small projector, mark the top view a 45mm below XY.

Video Lectures of Projections of Points