If you could see this building from an angle that combines all 3 of the "orthogonal" views (i.e., the 'right angle' views, conventionally chosen and labeled as the top, side, and front views) -- such as, for example, if there were a tall tree near this building, in front and off to one side, and you could climb it; or, if you could fly a drone up to that position, and photograph it -- the fourth view, below, is what this building would look like, from that angle.
Surprisingly, there is no good, reliable, unique name, in engineering drawings, for "a fourth view that has been assembled by combining three other views into a single view consistent with the other three."
That "fourth view" is often called an "isometric" view, among engineers, but that name has not just one, but TWO problems:
(1) the term "isometric" means, literally, that the dimensions in all directions are being held constant (metric = measurement, and "iso-" means "held the same"). And, for better or worse, that trait applies to ALL 4 of the views above. So, why should we call just ONE of them an isometric drawing, when all 4 of them are "isometric" drawings?
-- and --
(2) if that type of "isometric" view is altered, to make it even more accurate -- this is done, in so-called "perspective" drawings, by selecting "distant perspective" points on the horizon, far to the left and far to the right of a vertical "center line" in the drawing, and then forcing any and all horizontal lines in the drawing to point toward those distant horizon points -- then that fourth view could no longer be called an "isometric" drawing (at least, not accurately). It would need to be called, instead, a "perspective drawing" . . . which then becomes another non-unique and potentially misleading name for THAT drawing, since EVERY view is a "perspective view" from SOME perspective.
To fill that gap -- and to establish a larger point I want to make --
I propose to call that fourth view a "tetraheed" view.
Well . . . I'll explain on the next page.