Orthographic Projection Questions and Answers

Answer: C

It is a half section.

In a half section, two cutting planes at right angles remove one quarter of a symmetrical object. The view then shows half the object in section, revealing the interior, and the other half as an ordinary exterior view.

A full section cuts straight through the whole object and removes the front half. A removed section is a section drawn away from the view it belongs to, and 'quarter section' is not the standard name, even though a quarter is what gets cut away.

Answer: A

The section used is a revolved section.

A revolved section shows the shape of a part's cross-section by cutting it at a point, turning the section through 90° and drawing it on the view itself. It suits long members whose section changes along their length, such as crane hooks, spokes, arms and ribs.

A full section and a half section show the interior of a whole object rather than the section of a slender member. A removed section is the same idea drawn away from the view, usually where there is no room on the view itself, so the standard choice for a crane hook is the revolved section.

Answer: A

It is a leader.

A leader (leader line) is a thin continuous line drawn from a note or dimension to the feature it refers to. It ends in an arrowhead when it touches an outline and in a dot when it ends inside the outline of an object.

A dimension line shows the extent of a dimension and carries arrowheads at both ends. An extension (projection) line extends from the feature to the dimension line, and a cutting plane line, drawn chain thick at the ends, marks where a section is taken.

Answer: A

It is an isometric view.

In an isometric view the three principal edges of an object are equally inclined to the plane of projection, and the two horizontal axes are drawn at 30° to the horizontal, with the vertical axis upright.

A front view is an orthographic view drawn square to the object, an auxiliary view is projected onto a plane parallel to an inclined surface, and a perspective view uses vanishing points rather than fixed 30° axes.