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TOPIC 5 Sectional View

5.1 Introduction

An outside view of an object does not adequately describe it, as no internal features
are shown. In order to show the internal features without excessive use of hidden-detail

lines, the object is imagined to be cut along a plane called a cutting plane. The cut

portion nearer to the observer is removed and the remaining part is shown as a

sectional view. The surfaces in section can be imagined to be cut along the cutting
plane with an imaginary tool and imaginary cutting marks are represented by thin

equidistant hatching lines as shown in Figure 5.1. Sometimes hatching may be omitted, if

the clarity of drawing is not reduced by doing so.

Figure 5.1 Cutting plane

Sectional views are usually produced

(a) to clarify details of the object,

(b) to illustrate internal features clearly,

(c) to reduce the number of hidden-detail lines,

(d) to facilitate the dimensioning of internal features,

(e) to show the shape of the cross-section,

(f) to show clearly the relative positions of parts forming an assembly.