Question

The shortest distance between two parallel lines is equal to the length of the perpendicular drawn between them. If its true length is to be measured, then the two given parallel lines should be shown in their _________ views.

(a) top

(b) front

(c) point

(d) line

The question was posed to me in a national level competition.

This key question is from Projections on Auxiliary Planes topic in portion Orthographic Projection, Projections of Lines, Planes and Solids of Civil Engineering Drawing

Answer 1

Right option is (c) point

The best explanation: If the point views of the lines are required, then first they have to be shown in their true lengths in one of the orthographic views.

 If none of the orthographic views show the given lines in their true lengths, an auxiliary plane parallel to the two given lines should be set up to project them in their true lengths on it.

Even the auxiliary view which shows the lines in their true lengths may not show the perpendicular distance between them in true length. Hence another auxiliary plane perpendicular to the two given lines should be set up. Then the lines appear as points on this auxiliary plane and the distance between these point views will be the shortest distance between them.