Special Views - en011360018

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14.

SPECIAL VIEWS

When complex objects are involved, three-view

drawings are often not sufficient to convey all the

necessary details. Special views are added to provide

additional information. The special views which may

be encountered are auxiliary and rotation views,

sections, phantom views, developments, and

exploded views.

a. Auxiliary Views. If a feature of an object is

in a plane which is not parallel to one of the drawing

planes, it will not appear in true size or shape in any

of the three normal views. The sloping surface of the

object in figure 1-15, for example, appears in both the

top and right side views but is foreshortened in both.

In this case, an auxiliary projection is added. The

auxiliary view is obtained by projecting lines to a

drawing plane which is parallel to the slanted face.

Figure 1-16. Auxiliary view arrangement.

The auxiliary view is normally placed alongside a

view which shows the true length of the edge of the

perpendicular to one of the normal orthographic

slanted surface as shown in figure 1-16. In this case,

drawing planes, or if there is not enough room in the

the auxiliary view is related to the front view. If the

normal position, the auxiliary view will be placed

feature to be covered in an auxiliary view is not in a

somewhere else on the drawing. In this case; the

plane Figure 1-16. Auxiliary view arrangement,

auxiliary view will usually be labeled as "view A" (or

B, C, etc) with an arrow pointing to the face.

Auxiliary views do not usually show the entire object

as seen from the auxiliary view angle; only the

surface parallel to the auxiliary drawing plane is

covered. Figure 1-17 shows an auxiliary view

compared with a right side view of the same object.

Note that the circles appear as ellipses in the right

side view, and the distances between centers are

foreshortened. The auxiliary view only shows the

slanted face of the object, the holes appear in true

shape, and the distances in true length.

Figure 1-17. Auxiliary and side views compared.

Figure 1-15. Auxiliary projection principle