What line type indicates an edge that is not visible because it is obstructed by another surface?

The line type that indicates an edge that is not visible because it is obstructed by another surface is the hidden line. This line type is represented by a series of short dashes and is used in technical drawings to convey information about edges that are behind, blocked, or concealed by other parts of the object. By using hidden lines, designers and engineers can effectively communicate the full shape and features of an object, ensuring that important dimensions or features that are not directly visible are still represented in the drawing.

This kind of line helps maintain clarity in a drawing, allowing viewers to understand the internal structure and relationships of the components without having to rely solely on visible features. Thus, the use of hidden lines is essential in creating comprehensive and accurate technical documentation in engineering design.