What type of lines represent the material through which a cut is made to show an interior sectional view?

Section lines are specifically used in engineering drawings to represent the material through which a cut is made, providing a clear indication of an interior sectional view. These lines are typically drawn in a series of parallel diagonal lines that fill the area of the section view. This convention helps distinguish the cut surfaces from the non-sectioned areas, making it easier for engineers and designers to visualize and understand the internal features of a component or assembly.

In contrast, phantom lines are used to indicate extra features, dashed lines often depict hidden edges, and center lines are utilized to indicate the axes of symmetry. Each of these line types serves a distinct purpose in technical drawings, but when it comes to denoting material in section views, section lines are the standardized choice.