Lecture 9 TA 101 A Engineering Graphics 2018

Lecture 9 TA 101 A Engineering Graphics 2018 -19 -I By Dr. Mukesh Sharma Professor DEPARTMENT OF CIVIL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY KANPUR-208016, INDIA

Parallel Downward receding direction

Isometric and Oblique projections

Front View Right Side View Visualize the Object Oblique view of an object with Oblique surfaces

e, e’e” d, d’d” c b a 5, 5’, 5” 4, 4’, 4” 3, 3’, 3” 2, 2’, 2” 5 e 4 d 3 c 2 b 1, 1’, 1” 1 a 5’e’ 4’d’ 3’ c’ 2’b’ 5”e’’ 4”d” 3” c” 2”b” 1’ a’ Note: a’, a’’, b’’, c’c’’ exist but not shown Due to space limitation 1” a” 5” 4” e” Projection of front face in RSV, If front face not oblique but parallel to PP e’ 5 e b a b’ a’ 5’ 4’ 3” 3’ 4 2’ 1’ 3 2 1 2” 1”

Oblique View of Cylinder

What kind of 3 -d Pictures are these? As seen by eyes - Pleasing Perspective Pictures – How different are these from isometric/oblique drawing

Projection line Picture Pla ne Horizon line Axis of vision Horizo n Plan e SP Groun d Plan Center of vision Ground Line e

Objective is to get this picture on PP Key is convergence of rays at SP Picture Pla ne (PP) (transpare nt) X Horizon line (HL) PP AV cv Horizo n Plane (H SP TOP VIEW SP cv HL GL Front View Any Convenient Distance SP(EYE) P) Groun d Plane Center of vision (CV) Ground Line (GL)

b B A a a b b 1 b c d a ø ø a 1 C g h e a PP f b ø ø HL SP For A, B and C examine Projection on PP HL ø SP a PP LVP RVP d RVP g h e u c f b PP VP SP HL