LOCATION OF A POINT

A point lying in the space may be situated in the following positions with respect to principle planes of projections.

1. Point above the H.P and in front of the V.P.
2. Point above the H.P and behind the V.P.
3. Point below the H.P and behind the V.P.
4. Point below the H.P and in front of the V.P.
5. Point on the H.P and in front of the V.P.
6. Point above the H.P and on the V.P.
7. Point on the H.P and behind the V.P.
8. Point below the H.P and on the V.P.
9. Point on the H.P and V.P both

CONVENTIONAL REPRESENTATION

1. The actual position of a point is designated by the capital letters. i.e., A, B, C, P, Q, R, … etc.
2. The front view of a point is conventionally represented by small letters with dashes. i.e. a′, b′, c′, p′, q′, r′, …etc.
3. The top view of a point is conventionally represented by small letters. i.e., a, b, c, p, q, r, … etc.
4. The side view of a point is conventionally represented by small letters with double dashes. i.e., a″,b″, c″, p″, q″, r″, …etc.

The intersection of the reference planes is a line known as the reference line. It is denoted as xy. The reference line is drawn by a thin line. The line which connects the front view and the top view is called the projection line. It is drawn by a thin line. The projection line is always perpendicular to the principal axis (XY).

How to do projections of points?

PROJECTION OF POINTS (LECTURE-2) IN ENGINEERING DRAWING AND GRAPHICS