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10.14 Textbook of Enginnering Drawing-----------------
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t--+1'"""'1-'~ Top View
H--+--H--I----lf+-+--.I,::.....---r-L
Fig.l0.15(a) Vtsual ray method
Perspective Projection
- Since the comer b touches the picture plane, its perspective will be in its true positi()n.
- Since the lamina lies on the ground plane, bl is on GL and is also the perspective projection of
B. - From al draw vertical to intersect al Spl at A.
- Similarly obtain B, C and D.
- JointABCD and complete the perspective projection.
Vanishing Point Method (Fig. to.15h) - Draw the top view as explanted in Steps 1 to 4 in the above method.
- Draw GL and HL as shown.
Vanishing Points - From sp draw a line parallel to bc to intersect PP at VR
- Erect vertical from VR to intersect HL at vanishing point VRI
- Similarly from sp draw a line parallel to ba to cut PP at VL.
- Erect vertical from VL and obtain the other vanishing point VLI on HL.