What are leader lines used for?

Leader lines are utilized primarily to tie a dimension to a specific feature on a technical drawing. They serve as visual guides that clearly indicate which part of the drawing a particular measurement or annotation refers to. This is crucial in helping anyone reading the drawing to quickly understand the relationships between different parts and their dimensions without causing confusion.

By using leader lines, designers can ensure that dimensions are accurately portrayed in relation to the actual features on the drawing. This organization makes it easier for engineers, architects, and manufacturers to interpret the design accurately, improving the communication of specifications and enhancing overall clarity in technical documentation.

In contrast to the other options, connecting dimensions or illustrating motion falls outside the primary purpose of leader lines, while indicating the depth of an object is typically accomplished through other means, such as sectional views or depth indicators.