An auxiliary view is an orthographic view. taken in one this way that the lines of sight aren't parallel to the important projection planes (frontal, horizontal, or profile). There are an endlessly wide variety of viable auxiliary perspectives of any given object.
For example, if the willing surface is visible within the frontal aircraft, then such an auxiliary view may be called Frontal Auxiliary View.
Learn more about commonly used to show holes on angled faces that would otherwise not appear circular here
