Chapter 8 - Cylindrical Surfaces in Orthographic Projections

Negative Cylinder

Shown above is what will be defined as a negative cylinder or, in more common terms, a hole. The limits of curvature of the cylindrical surface appear as lines in the rectangular views, that is, the top and side views. For example, Element A appears as an edge or a line in the top view. There is no true edge on that cylindrical surface, however there is a limit of curvature which is represented by a line. The cylindrical surface appears as a rectangle in the top and side views, and it appears as a circle in the front view.