The cutaway perspective is fundamentally a three dimensional sectional view.

It is particularly suitable for subjects that are basically cylindrical or have a central axis, such as pumps, valves and filters, and the usual practice is to cut away a quarter segment to expose the inner details while still maintaining the external shape. Of course, the technique can be applied to any subject, and the cutaway portion can be any shape or size, providing it is clearly presented and the object is still recognisable. As with the orthographic section, this type of illustration is particularly suitable for showing internal flow and principles of operation.

Source:

Lightfoot, Peter. "Illustration (information-graphics) for technical publications". Professional Communication and Information Design. St. Neots, Cambridgeshire: Institute of Scientific and Technical Communicators, 2001. 116-117.

The ISTC publication can be ordered here.

About the author:

Peter Lightfoot has spent a career within technical illustration and information graphics, which spans more than four decades. It also spans the period that included the high point in traditional technical line and tonal airbrush illustration through the transition to digital illustration and desktop publishing. This career followed a mechanical engineering apprenticeship, and subsequently led to work in the aircraft, shipbuilding, petro-chemical, oil & gas, machine tool and automotive industries carrying out tasks that cover all aspects of information graphics. He is currently a founder and director of Media 4 Graphix Ltd. who specialise in the production of conventional and on-line technical and commercial promotional material. Peter can be contacted via email at Peter@media4.co.uk.