Isometric Projections Dept. of Mechanical Engineering Engineering Graphics F.Y. B.Tech. SEM - I Dept. of Mechanical Engineering

Isometric Projections: It is a type of pictorial projection in which all three dimensions of an object are shown in one view. In this, 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 (120o). a b c

Isometric Planes: The planes representing the faces of the cube 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. In practice, while drawing isometric projection, it is necessary to convert true lengths into isometric lengths.

Isometric scale ( Line AC ) required for Isometric Projection 4 3 C 2 TRUE LENGTHS 4 1 3 2 ISOM. LENGTHS 1 450 300 A B Isometric scale ( Line AC ) required for Isometric Projection

A C D G H 30o Base Line M N B F E 120o

T.V. L.H.S.V. F.V. L.H.S.V. F.V. X T.V.

T.V R.H.S.V F.V F.V R.H.S.V X T.V

Isometric view if the Shape is F.V. or T.V. D A B C H L D A B C L A B RECTANGLE D C 1 2 A B H L ISOMETRIC OF PLANE FIGURES TRIANGLE 3 1 2 A B 1 2 3 A B 3 D L 1 2 3 4 PENTAGON A B C D E A B C D E H L 1 2 3 4 1 2 3 4 A B C D E D L

Ellipses can be in any of three planes Ellipse could appear in any one of the three planes (front, profile or side, horizontal or top) Major axis (long axis) of the ellipse will be along the long diagonal of the rectangle Minor axis (short axis) along the shorter diagonal. Note ellipse must have the correct orientation in the box. (Almost fills the box, if rotated 90 degrees, it would be incorrect for the plane of view.)

34 60 25 L= 60 mm H= 25 mm D= 34 mm X

Draw isometric drawing from given orthographic view Example 2 Draw isometric drawing from given orthographic view O O

Solution 2

FV TV X Y O 40 10 25 30 R 100 30 20 D O

40 10 50 80 30 D 45 FV TV O O

O 20 15 30 60 40 100 50 HEX PART O

34 60 25 L= 60 mm H= 25 mm D= 34 mm X