What is the function of an extension line in an orthographic drawing?

An extension line is used in orthographic drawings to define the extent of distance, indicating the boundaries that dimensions refer to. It is essential for clearly communicating measurements by extending from the object representation to a dimension line. This ensures that the reader understands the specific area referred to in the dimension, accurately showing where the measurement begins and ends. In practical application, extension lines help eliminate ambiguity by clearly connecting dimensions to the relevant parts of the drawing, facilitating a proper understanding during construction or fabrication.