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ISOMETRIC DRAWING, IT IS A TYPE OF PICTORIAL PROJECTION, IN WHICH ALL THREE DIMENSIONS OF, AN OBJECT ARE SHOWN IN ONE VIEW AND, IF REQUIRED, THEIR ACTUAL SIZES CAN BE, MEASURED DIRECTLY FROM IT., , 3-D DRAWINGS CAN BE DRAWN, IN NUMEROUS WAYS AS SHOWN BELOW., ALL THESE DRAWINGS MAY BE CALLED, 3-DIMENSIONAL DRAWINGS,, OR PHOTOGRAPHIC, OR PICTORIAL DRAWINGS., HERE NO SPECIFIC RELATION, AMONG H, L & D AXES IS MENTAINED., , TYPICAL CONDITION., IN THIS 3-D DRAWING, AN OBJECT IS SO PLACED, THAT, ITS THREE MUTUALLY PERPENDICULAR, EDGES ARE EQUALLY INCLINED WITH THE PLANE, OF PROJECTION. SO ALL THREE DIMENSIONAL, AXES APPEAR AT EQUAL INCLINATIONS WITH, EACH OTHER.( 1200), , NOW OBSERVE BELOW GIVEN DRAWINGS., ONE CAN NOTE SPECIFIC INCLINATION, AMONG H, L & D AXES., ISO MEANS SAME, SIMILAR OR EQUAL., HERE ONE CAN FIND, EQUAL INCLINATION AMONG H, L & D AXES., EACH IS 1200 INCLINED WITH OTHER TWO., HENCE IT IS CALLED ISOMETRIC DRAWING, , L, , H, , H, , H, , PURPOSE OF ISOMETRIC DRAWING IS TO UNDERSTAND, OVERALL SHAPE, SIZE & APPEARANCE OF AN OBJECT PRIOR TO IT‟S PRODUCTION.
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SOME IMPORTANT TERMS:, ISOMETRIC AXES, LINES AND PLANES:, The three lines AL, AD and AH, meeting at point A and making, 1200 angles with each other are termed Isometric Axes., The lines parallel to these axes are called Isometric Lines., , A, , The planes representing the faces of of the cube as well as, other planes parallel to these planes are called Isometric Planes., ISOMETRIC SCALE:, When one holds the object in such a way that all three dimensions, are visible then in the process all dimensions become proportionally, inclined to observer‟s eye sight and hence appear apparent in lengths., This reduction is 0.815 or 9 / 11 ( approx.) It forms a reducing scale which, Is used to draw isometric drawings and is called Isometric scale., In practice, while drawing isometric projection, it is necessary to convert, true lengths into isometric lengths for measuring and marking the sizes., This is conveniently done by constructing an isometric scale as described, on next page., , H
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Problem 13.23: A cube of 25 mm, long edges is so placed on HP on one, corner that a body diagonal is, parallel to HP and perpendicular to, VP Draw it’s projections., , Solution Steps:, 1.Assuming standing on HP, begin with TV,a square with all sides, equally inclined to XY. Project FV and name all points of FV & TV., 2.Draw a body-diagonal joining c’ with 1’( This can become // to xy), 3.From 3’ drop a perpendicular on this and name it p’, 4.Draw 2nd Fv in which 3’p’ line is vertical means c’-1’ diagonal, must be horizontal. .Now as usual project TV.., 6.In final TV draw same diagonal is perpendicular to VP as said in problem., Then as usual project final FV., , a1’, , a’, , b’d’, , c’, , c1 ’, 11’, , 1’, , 21’, , 2’ 4’, , X, , 1’, , 2’ 4’, , 41, , c3, , b2, , 41’, 3 1 ’1, , 3’, , 3’, , d4, , a1, , d1’, , b1’, , 11, , a1, , 21, , Y, 1, , d1, , 31, , b1, , c1, , 21, , 41, , b1, , d1, , c1
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TYPES OF ISOMETRIC DRAWINGS, , ISOMETRIC VIEW, , ISOMETRIC PROJECTION, , Drawn by using True scale, ( True dimensions ), , Drawn by using Isometric scale, ( Reduced dimensions ), , 4, , D, , 3, , H, , C, , 2, , H, , 4, 3, , 1, 2, 0, , 0, , 1, , 300, , 450, , A, , B, , Isometric scale [ Line AC ], required for Isometric Projection, , CONSTRUCTION OF ISOM.SCALE., From point A, with line AB draw 300 and, 450 inclined lines AC & AD resp on AD., Mark divisions of true length and from, each division-point draw vertical lines, upto AC line., The divisions thus obtained on AC, give lengths on isometric scale.
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1, , D, , H, , D, , RECTANGLE, , A, AS THESE ALL ARE, 2- D FIGURES, WE REQUIRE ONLY, TWO ISOMETRIC, AXES., , Isometric view if the Shape is, F.V., or, T.V., , SHAPE, , ISOMETRIC, OF, PLANE FIGURES, , D, , A, C, , C, A, , B, , C, , B, , B, B, , IF THE FIGURE IS, FRONT VIEW, H & L, 1, AXES ARE REQUIRED., , H, TRIANGLE, , B, , 3, , B, , 3, , 1, , A, 3, , IF THE FIGURE IS TOP, VIEW, D & L AXES ARE, 2, REQUIRED., , Shapes containing, Inclined lines should, be enclosed in a, rectangle as shown., Then first draw isom., of that rectangle and, then inscribe that, shape as it is., , A, , A, 1, , 2, , 2, 4, , H, , PENTAGON, E, , 1, , 4, D, , A, , E, , 1, , D, , 4, D, , E, A, , 1, 3, C, , 2, , B, , C, , 3, , 2, , B, , 3, C, , A, B, , 2
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STUDY, ILLUSTZRATIONS, , 2, , DRAW ISOMETRIC VIEW OF A, CIRCLE IF IT IS A TV OR FV., FIRST ENCLOSE IT IN A SQUARE., IT‟S ISOMETRIC IS A RHOMBUS WITH, D & L AXES FOR TOP VIEW., THEN USE H & L AXES FOR ISOMETRIC, WHEN IT IS FRONT VIEW., FOR CONSTRUCTION USE RHOMBUS, METHOD SHOWN HERE. STUDY IT., , 2, B, , A, 4, , 3, , C, , D, , 1
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3, , STU DY, Z, ILLUSTRATIONS, 25 R, , DRAW ISOMETRIC VIEW OF THE FIGURE, SHOWN WITH DIMENTIONS (ON RIGHT SIDE), CONSIDERING IT FIRST AS F.V. AND THEN T.V., , 50 MM, , IF FRONT VIEW, , 100 MM, , IF TOP VIEW
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ISOMETRIC, OF, PLANE FIGURES, , AS THESE ALL ARE, 2-D FIGURES, WE REQUIRE ONLY, TWO ISOMETRIC, AXES., , SHAPE, , IF F.V., , IF T.V., , 4, , HEXAGON, , CIRCLE, , IF THE FIGURE IS, FRONT VIEW, H & L, AXES ARE, REQUIRED., IF THE FIGURE IS, For Isometric of Circle/Semicircle use Rhombus method. Construct Rhombus, TOP VIEW, D & L, of sides equal to Diameter of circle always. ( Ref. topic ENGG. CURVES.), AXES ARE, SEMI CIRCLE, REQUIRED., For Isometric of, Circle/Semicircle, use Rhombus method., Construct it of sides equal, to diameter of circle always., ( Ref. Previous two pages.)
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5, , STUDY, ILLUSTRZATIONS, , ISOMETRIC VIEW OF, PENTAGONAL PYRAMID, STANDING ON H.P., (Height is added from center of pentagon), , ISOMETRIC VIEW OF BASE OF, PENTAGONAL PYRAMID, STANDING ON H.P., , 4, 4, , D, , D, , E, , E, , 1, , 3, C, , A, B, , 1, , 3, C, , A, , 2, B, , 2
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6, , STUDY, ILLUSTRZATIONS, ISOMETRIC VIEW OF, , PENTAGONALL PRISM, LYING ON H.P., , 4, H, , E, , 1, , D, , A, , 3, C, , 2, , ISOMETRIC VIEW OF, , HEXAGONAL PRISM, STANDING ON H.P., , B
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7, , STUDY, ILLUSTRZATIONS, CYLINDER STANDING ON H.P., , CYLINDER LYING ON H.P.
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8, , STUDY, ILLUSTRZATIONS, , HALF CYLINDER, STANDING ON H.P., ( ON IT’S SEMICIRCULAR BASE), , HALF CYLINDER, LYING ON H.P., ( with flat face // to H.P.)
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STUDY, ILLUSTRZATIONS, , 60, , FV, , X, , 40, , Y, , 20, , TV, , ISOMETRIC VIEW OF, A FRUSTOM OF SQUARE PYRAMID, STANDING ON H.P. ON IT’S LARGER BASE., , 9
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STUDY, ILLUSTRATION, , 10, , ISOMETRIC VIEW, OF, FRUSTOM OF PENTAGONAL PYRAMID, , PROJECTIONS OF FRUSTOM OF, PENTAGONAL PYRAMID ARE GIVEN., DRAW IT‟S ISOMETRIC VIEW., , SOLUTION STEPS:, , 60, , FV, , FIRST DRAW ISOMETRIC, OF IT‟S BASE., , y, , x, 1, , E, , 4, , THEN DRAWSAME SHAPE, AS TOP, 60 MM ABOVE THE, BASE PENTAGON CENTER., , D, , THEN REDUCE THE TOP TO, 20 MM SIDES AND JOIN WITH, THE PROPER BASE CORNERS., , A, , TV 40 20, B, , 2, C, , 3
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ISOMETRIC VIEW OF, 11, A FRUSTOM OF CONE, STANDING ON H.P. ON IT’S LARGER BASE., , STUDY, ILLUSTRZATIONS, , 60, , FV, , X, , 40, , Y, , 20, , TV
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STUDY, ILLUSTRZATIONS, , PROBLEM: A SQUARE PYRAMID OF 30 MM BASE SIDES AND, 50 MM LONG AXIS, IS CENTRALLY PLACED ON THE TOP OF A, CUBE OF 50 MM LONG EDGES.DRAW ISOMETRIC VIEW OF THE PAIR., , 12
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STUDY, ILLUSTRZATIONS, , FV, , 30, 10, 30, , 30 D, , 50, , +, , 50, , TV, , PROBLEM:, A SQUARE PLATE IS PIERCED THROUGH CENTRALLY, BY A CYLINDER WHICH COMES OUT EQUALLY FROM BOTH FACES, OF PLATE. IT‟S FV & TV ARE SHOWN. DRAW ISOMETRIC VIEW., , 14
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STUDY, ILLUST RATIONS ISOMETRIC, , Z, , PROJECTIONS OF SPHERE & HEMISPHERE, , 17, , r, , 450, 300, , r, , R, r, , Isom. Scale, , P, C, , r, R, , r, C, , R, R, , r, , P, , TO DRAW ISOMETRIC PROJECTION, OF A HEMISPHERE, , P, C = Center of Sphere., P = Point of contact, R = True Radius of Sphere, r = Isometric Radius., TO DRAW ISOMETRIC PROJECTION OF A SPHERE, 1. FIRST DRAW ISOMETRIC OF SQUARE PLATE., 2. LOCATE IT‟S CENTER. NAME IT P., 3. FROM PDRAW VERTICAL LINE UPWARD, LENGTH „ r mm‟, AND LOCATE CENTER OF SPHERE “C”, 4. „C‟ AS CENTER, WITH RADIUS „R‟ DRAW CIRCLE., THIS IS ISOMETRIC PROJECTION OF A SPHERE., , Adopt same procedure., Draw lower semicircle only., Then around „C‟ construct, Rhombus of Sides equal to, Isometric Diameter., For this use iso-scale., Then construct ellipse in, this Rhombus as usual, And Complete, Isometric-Projection, of Hemi-sphere.
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18, , PROBLEM:, A HEMI-SPHERE IS CENTRALLY PLACED, ON THE TOP OF A FRUSTOM OF CONE., DRAW ISOMETRIC PROJECTIONS OF THE ASSEMBLY., , Z, , r, 50 D, , r, , R, 30 D, , r, , 50, , P, , 50 D, FIRST CONSTRUCT ISOMETRIC SCALE., USE THIS SCALE FOR ALL DIMENSIONS, IN THIS PROBLEM., , 450, 300, , STU DY, ILLUSTRATIONS
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19, , STUDY, ILLUSTRZATIONS, , A SQUARE PYRAMID OF 40 MM BASE SIDES AND 60 MM AXIS, IS CUT BY AN INCLINED SECTION PLANE THROUGH THE MID POINT, OF AXIS AS SHOWN.DRAW ISOMETRIC VIEW OF SECTION OF PYRAMID., , 3’ 4’, 4, 1’2’, , 3, , X, , Y, a, , 1, , d, , 1, 4, , 2, o, , b, , 2, , 3, c
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20, , STUDY, ILLUSTRZATIONS, , F.V. & T.V. of an object are given. Draw it‟s isometric view., , 50, , X, , O, , Y, , 20, , 25, , O, , 25, , 20
