Question

In _________ the parallel projection rays are not perpendicular to the viewing plane as with orthographic projection, but strike the projection plane at an angle other than ninety degrees.

(a) isometric projections

(b) orthographic projections

(c) axonometric projection

(d) oblique projections

This question was addressed to me in an interview for internship.

This is a very interesting question from Projections on Auxiliary Planes in division Orthographic Projection, Projections of Lines, Planes and Solids of Civil Engineering Drawing

Answer 1

Correct option is (d) oblique projections

To explain: In both orthographic and oblique projection, parallel lines in space appear parallel on the projected image. Because of its simplicity, oblique projection is used exclusively for pictorial purposes rather than for formal, working drawings. In an oblique pictorial drawing, the displayed angles among the axes as well as the foreshortening factors (scale) are arbitrary. The distortion created thereby is usually attenuated by aligning one plane of the imaged object to be parallel with the plane of projection thereby creating a true shape, full-size image of the chosen plane.