Auxiliary ViewsFigure 3-11.—A three-view drawing.PERSPECTIVE DRAWINGSA perspective drawing is the most used method ofpresentation used in technical illustrations in thecommercial and architectural fields. The drawnobjects appear proportionately smaller with distance,as they do when you look at the real object (fig. 3-12).It is difficult to draw, and since the drawings are drawnin diminishing proportion to the edges represented,they cannot be used to manufacture an object. Otherviews are used to make objects and we will discusthem in the following paragraphs.SPECIAL VIEWSIn many complex objects it is often difficult toshow true size and shapes orthographically.Therefore, the draftsmen must use other views to giveengineers and craftsmen a clear picture of the objectto be constructed. Among these are a number ofspecial views, some of which we will discuss in thefollowing paragraphs.Auxiliary views are often necessary to show thetrue shape and length of inclined surfaces, or otherfeatures that are not parallel to the principal planes ofprojection.Look directly at the front view of figure 3-13.Notice the inclined surface. Now look at the right sideand top views. The inclined surface appearsforeshortened, not its true shape or size. In this case,the draftsman will use an auxiliary view to show thetrue shape and size of the inclined face of the object.It is drawn by looking perpendicular to the inclinedsurface. Figure 3-14 shows the principle of theauxiliary view.Look back to figure 3-10, which shows an immov-able object being viewed from the front, top, and side.Find the three orthographic views, and compare themFigure 3-13.—Auxiliary view arrangement.Figure 3-12.—The perspective.Figure 3-14.—Auxiliary projection principle.3-5
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