1. The Correct Treatment of
Hidden Lines

2. It is necessary to to describe every part of an object
It is necessary to to describe every part of an object. Therefore, everything must be represented in each view, whether or not it can be seen. Both interior and exterior features are projected in the same way. Parts that cannot be seen in the views are drawn with Hidden Lines.

3. Hidden Lines are thin dashed lines used to indicate a surface, edge, or contour of an object that cannot be seen, or is hidden from view.

4. Average hidden line convention

5. Drawing conventions for hidden lines
The following views show correct and incorrect drawing conventions for hidden lines.

14. THE END