Copyright Goodheart-Willcox Co., Inc. 22 Section 1 Introduction to Drafting and Print Reading Goodheart-Willcox Publisher Figure 2‑5. Cutting-plane lines can be made in different ways, but the method indicated in A is common. Section lines, shown in B, are thin, continuous lines usually drawn at 45° and about 1/8″ apart. A B Cutting-plane line Center lines Section lines Goodheart-Willcox Publisher Figure 2‑6. Dimension lines are thin lines used to indicate the extent and direction of part dimensions, while the extension lines extend the object. Leaders are characterized by an arrow on one end and a shoulder on the other end, which is vertically centered with the beginning or end of the note. Extension line Dimension line Leader Dimension line Leader