Question

The positions of reference line and top view in 1st angle projection are __________

(a) reference line lies above the top view

(b) reference line lies below the top view

(c) reference line lie left side to top view

(d) reference line lie right side to top view

This question was addressed to me in an interview.

Origin of the question is First Angle Projection Method in section Loci of Points & Orthographic Projections of Engineering Drawing

Answer 1

Correct choice is (a) reference line lies above the top view

The explanation is: Reference line will be the xy line which is formed by intersection of vertical plane and horizontal plane. In the first angle projection the projections of object is taken by placing object in 1st quadrant and top view is projected on to horizontal plane which is after the reference line.