An important reason for using section views is to reduce the number of hidden lines in a drawing. A section view reveals hidden features without the use of hidden lines. Adding hidden lines to a section view complicates the drawing defeating the purpose of clarifying with a section. As illustrated in figure 5, there are times, when a minimum number of hidden lines are needed to represent features other than the primary one shown by the section. In the figure, the through and through cavity may not be represented properly since it could be mistaken with a circular hole.

Figure 5 Illustration of the need of section view.

Figure 6  illustrates a full section view of an object. As shown in the correct drawing, the section lined areas are bounded by visible lines, never by hidden lines, because the bounding lines are visible in the section view Visible surfaces and edges that represent a change of planes behind the cutting plane are drawn as lines in a section view.
Figure 6  shows a section view for which the cutting plane passes through the center of a counter bored hole. A line represents the change of planes between the drilled and counter bored holes and is an example of a visible feature that is behind the cutting plane.

Figure 6  Shows a correct and incorrect representation along with the multiview drawing