It is possible that lines representing two different surfaces of an object shown in one view would, when shown in another view, appear as one line. This tends to make the drawing confusing and more difficult to read. Therefore, one of these lines may be shown out of true projection in order to show the edges of the two different surfaces, as illustrated in Figure 7.15.
(a) TRUE PROJECTION (b) UNTRUE PROJECTION
NOTE: A and В in Figure 7-15(a) are represented in the right side view by the same line. In Figure 7-15(b), A and В are represented by two lines. Although this is considered a violation, it is nevertheless used occasionally.