Textbook of Engineering Drawing, Second Edition

5.8 Textbook of Enginnering Drawing------------------

Knowing the distances of a point from H.P and V.P, projections on H.P and Y.P are found by
extending the projections perpendicular to both the planes. Projection on H.P is called Top view
and projection on Y.P is called Front view

Notation followed

1. Actual points in space are denoted by capital letters A, B, C.


2. Their front views are denoted by their corresponding lower case letters with dashes ai, bl, d,
   etc., and their top views by the lower case letters a, b, c etc.


3. Projectors are always drawn as continious thin lines.
   Note:


4. Students are advised to make their own paper/card board/perplex model ofH.P and V.P as
   shown in Fig.5.4. The model will facilitate developing a good concept of the relative position
   of the points lying in any of the four quadrants.


5. Since the projections of points, lines and planes are the basic chapters for the subsequent
   topics on solids viz, projection of solids, development, pictorial drawings and conversion of
   pictorial to orthographic and vice versa, the students should follow these basic chapters
   carefully to draw the projections.

Problem: Point A is 40 mm above HP and 60 mm in front of v.P. Draw its front and top view.

Solution: (Fig.5.9)

1. The point A lies in the I Quadrant

VP a'

~ a'^0 -.r

x

(^0) -.r
~()'
~o
VP
X Y
HP^0
Y
(^0) <0^0 <0
a HP a
(b) (c)
Fig. 5.9 Orthographic projection ofa point in First Quadrant