978 1 58503 387 4 A Concise Introduction to Engineering

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Chapter 4 Multiview Drawing,Copyrighted,manufactured or constructed without first making. multiview drawings,Orthographic Projection,Orthographic projection is the projection theory. used to make multiview drawings The easiest way, to understand orthographic projection is to envision. Multiview Drawing an object placed inside a rectangular box made of. sheets of plastic as illustrated in Figure MVD2 The. arrows illustrate viewing positions of the six, The Engine of Industry principle orthographic views. Multiview drawings are the most common type, of technical drawings for both the machine and Top.
architectural industries As the name implies a,Copyrighted. multiview drawing is multiple views of a single,object For example Figure MVD 1 is a multiview. sketch of a table lamp showing the lamps front top. and right side views A single view of the lamp,would not describe its exact shape You need at. least these three views to envision its shape, Copyrighted Figure MVD 2 Object encased in a clear plastic. box with arrows locating the viewing position of the. six principle orthographic views,Each of its six clear plastic sides is called a.
plane of projection Each side of the object is, projected onto one of the six planes of projection. For example in Figure MVD 3 the front view of,the object is projected onto the front plane of. projection with lines called projection rays,Copyrighted. Figure MVD 1 Sketch showing the front top and,right views of a table lamp. Normally when people refer to blue prints, they are not referring to traditional drawing that.
have white lines on a blue background They are, referring to any technical drawing These technical. drawings are multiview drawings and they are the,engine that runs industry because nothing is. Chapter 4 Multiview Drawing,Copyrighted,views is maintained This means the top front and. bottom views line up and the front right left and,back views line up Projectability of views must. ALWAYS be maintained when sketching drafting,or laying out views in CAD.
Copyrighted,Figure MVD 3 Projection rays projecting the front. view of the object onto the front plane of projection. Projection rays are parallel to each other and,perpendicular to the plane of projection The. resulting front orthographic view is illustrated in. Figure MVD 4,Figure MVD 5 All six planes of projection being. unfolded about the front plane,Copyrighted,Figure MVD 4 Resulting front orthographic view as. projected onto the front plane of projection,To obtain another view of the object the.
viewer must either change their viewing position or. rotate the object until their line of sight is,perpendicular to one of the six sheets of plastic. Back Left Right,The Six Plastic Planes of Projection. The top front right left bottom and back Bottom, make up the six principal orthographic views of an. Copyrighted, object In order to describe a 3 D object on a 2 D Figure MVD 6 All six sides of the plastic box. piece of paper the six principle orthographic views unfolded into the 2 D plane of a piece of paper. must be unfolded into a single plane Figure MVD, 5 illustrates the plastic box unfolding with the Figure MVD 7 illustrates the relationship of.
views being hinged about the front view Figure height width and depth between the views Note. MVD 6 illustrates the six principle projection that each individual view only has two of the three. planes completely unfolded into a single plane The dimensions height width and depth thus 2 D. result is the correct layout of the six principle drawing. orthographic views Note that the projectability of. Chapter 4 Multiview Drawing,Copyrighted,Top Even though each orthographic view in a. multiview is only 2 D it is helpful to envision each. view as it if it were 3 D Figure MVD 9 illustrates. the six principle views of the 3 D letter L Planes. in or parallel to a principle plane of projection are. Width shaded while planes perpendicular to a principle. plane of projection are labeled EV for edge view, Note that the planes labeled EV appear as lines in. their respective planes of projection,Depth Depth,Copyrighted. Figure MVD 7 Relationship between height width,Figure MVD 8 provides a look of how a. 45 miter line is used to transfer depth between the. top and right views The 45 miter line starts at the. intersection of lines 1 and 2 Lines 1 and 2 radiate. from the edge views EV of the frontal planes in,the top and right views Line 3 helps transfer the.
small notch from the right to the top view Line 4, 5 and 6 help transfer the hole from the top to the. right view Using the 45 miter line makes it both, faster to construct a multiview drawing and allows. Copyrighted, you to check yourself with respect to the right top. Figure MVD 9 The 3 D letter L with planes in or, and left top relationships parallel to a principle plane shaded and planes. perpendicular to a principle plane labeled EV,5 2 D Planes.
Each orthographic view of a multiview drawing, is two dimensional For example if you look at just. the front view of Figure MVD 10 you cannot tell, that plane A is the front most plane while B and C. are further back Similarly if you look at the top,view of Figure MVD 10 you cannot tell that plane. D is higher than E and if you look at the right view. you cannot tell that plane F is closer than plane G. Copyrighted, Figure MVD 8 The 45 miter line is used to transfer. details between the top and right views,Chapter 4 Multiview Drawing.
Copyrighted C,Material Top,Copyrighted,Front Right Front Right. Figure MVD10 No way of telling which plane is Figure MVD11 Normal plane A is true size and. closer shape in the front view and is in edge view in the. top and right views,Types of Planes, The examples and exercises in this text are Inclined Planes. limited to normal inclined oblique and single An inclined plane is not parallel to any of the. curved surfaces Each of these four will be principle planes Therefore it does not show its true. discussed and illustrated in this text Double curved size and shape in any of the principle views An. and warped surfaces are considered too advanced inclined plane will be perpendicular to the six. for this text principle planes and display as a similar shape in. the others four For example plane B in Figure, Normal Planes MVD 12 displays as an edge view in the front view. Copyrighted, A normal plane is parallel to two principle because plane B is perpendicular to the front plane. planes and projects as an edge view in the other of projection and as similar foreshortened. four When a plane is parallel to a principle plane it rectilinear shapes in both the top and right views. projects its true size and shape TSS For example,the normal surface A in Figure MVD 11 projects.
its TSS in the front view and projects as an edge,view line in both the top and the right views. Similar Shapes,Copyrighted,Front Right, Material Figure MVD 12 Inclined plane B is in edge view. in the front view and similar though foreshortened. shapes in the top and right views,Chapter 4 Multiview Drawing. Copyrighted,Oblique Planes Edges,An oblique plane is not parallel nor is it of Cyl. perpendicular to any of the six principle projection. planes Therefore it does not display its true size. and shape or as an edge view in any view An,oblique plane does show the same number of sides.
and the same number of corners in all six principle. views as plane C illustrates in Figure MVD 13 Top, Oblique planes can be difficult to draw unless EV Edge. the following rules are understood and applied,1 parallel lines are ALWAYS parallel and. 2 when parallel planes are sliced at an angle by EV Edges. another plane the resulting lines of intersection of Cyl. are parallel Edge,Copyrighted,3 6 Front Right,5 Figure MVD 14 Single curved surfaces display as. C C edge views in the front view and as lines in the top. Top 7 and right views,7 Line and Surfaces, 1 2 3 4 1 2 3 4 This text concentrates on flat and single curved. 5 6 surfaces It is easier to visualize an object from. 5 6 multiview drawings if you know how lines arcs,C C and circles are formed Refer to Figure MVD 15.
when visualizing the ways geometry is formed,Copyrighted. 7 7 A straight line is formed when,Front Right 1 viewing the EV of a flat plane. 2 two flat planes intersect, Figure MVD 13 Oblique plane C with the same 3 viewing the edge lines of a cylinder cone torus. number of sides and corners in all views doughnut or extruded arc. Single Curved Surfaces,An arc or circle is formed when. A single curved surface is formed by extruding,1 viewing the edge view of a curved surface.
stretching out a circle an arc or an irregular,2 looking down into a hole. curve Figure MVD 14 illustrates an extruded circle. 3 viewing the end of a cylinder,and two extruded arcs An extruded circle forms. either a hole or a solid cylinder like a coffee can. An extruded arc forms a smooth curved surface,such as the rolled front edge of many kitchen. Copyrighted,counters An extruded irregular curve forms a. rolling curved surface like a child s slide found at a. playground The front view in Figure MVD 14, displays the EV of two arcs and one circle The top.
and right views display the edge lines of the hole. and the right view displays the edge line of the two. arcs and one cylinder,Chapter 4 Multiview Drawing,Copyrighted. EV E Cyl G,Top Top plane,EV B EV C EV Edge view of. Cyl G inclined plane,Cyl G EV D F,B B E Front Right. Copyrighted,Front Right, Intersection Figure MVD 17 A hole appears as an ellipse when. of A B in an inclined plane, Figure MVD 15 Lines formed by the intersection of When a circle is rotated about an axis it.
planes EV of planes and edges of arcs or,changes into an ellipse The shape of the ellipse. depends on how much the ellipse is rotated Figure, Top MVD 18 shows a circle being rotated about an axis. When the circle is in the 0 position it appears as an. edge view line in the front view A full, 90 rotation produces a true circle in the front view. A 30 or 60 rotation of the circle produces an, ellipse The flatness of the ellipse depends on how. much it is rotated A 30 rotation produces an,Copyrighted.
ellipse that is flatter than the ellipse produced by. rotating the circle 60 Note that the length of the. ellipses major axis AB in the front view of Figure. MVD 18 does not change It remains equal to the, circle s original diameter But the minor axis CD of. the 30 rotated circle is shorter than the minor axis. EF of the 60 rotated circle,Full circle,w 90 rotation. Figure MVD 16 Circles and arcs in normal planes 30. Circles vs Ellipses A B,Copyrighted,Holes and solid cylinders appear as circles. when they are on normal surfaces as illustrated in. Figure MVD 16 But when they lie on an inclined Axis of Edge view B A. plane they appear as ellipses as illustrated in Figure rotation of circle. MVD 17 Line, Material Figure MVD 18 The rotating circle starts as a line. then forms two different ellipses and finally a full. Chapter 4 Multiview Drawing,Copyrighted,3rd Angle vs 1st Angle Projection Bottom.
To this point and for the remainder of the text,multiview drawing has been discussed and. illustrated using 3rd angle projection This is the. projection system used in the United States, However most countries use 1st angle projection to. create multiview drawings In 1st angle projection, the object is positioned in front of the plastic planes. as illustrated in Figure MVD 19 Views are still,hinged off the front view and result in the view. Back Right Left,placement illustrated in Figure MVD 20 Note how.
the positions of the views differ from 3rd angle,projection To ensure that those reading the. drawing know whether it is 3rd or 1st angle Top,Copyrighted. projection use one of the two symbols illustrated in. Figure MVD 21 Figure MVD 20 Positioning of the six principle. Top views in 1st angle projection,Material 1st Angle 3rd Angle. Projection Symbol Projection Symbol,Figure MVD 21 1st and 3rd angle projection. Copyrighted,symbols placed in or near the title block.
Figure MVD 19 the object is placed in front of the. plastic planes in 1st angle projection,Copyrighted. A Concise Introduction to Engineering Graphics and Supplemental Workbook Third Edition Timothy J Sexton Professor Department of Industrial Technology Ohio University SDC Schroff Development Corporation www schroff com www schroff europe com PUBLICATIONS

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