Question

The distance between the end projectors of a straight line AB is 60 mm. Point A is 5 mm above HP and

30 mm in front of VP. Point B is 40 mm above HP and 50 mm behind VP. Draw the projections and

find the inclination of straight line AB with HP and VP and the true length of the line.​

Answer 1

Explanation:

Given Data:-

Distance between End Projectors (DBEP) = 60 mm

a’ (↑) = 25 mm

a (→) = 45 mm

b’ (↑) = 60 mm

b (→) = 15 mm

Follow the procedure given below step by step to draw the projection of line –

Draw XY line.

Mark a’ and a at 25 mm above XY line and 45 mm below XY line respectively.

Draw horizontal line from a’ and a.

Mark b’ and b at 60 mm above XY line and 15 mm below XY line respectively.

Draw horizontal line from b’ and b and name it locus of b’ and locus of b respectively.

Mark a point at DBEP = 60 mm measuring from point a’ and draw a vertical line from that point.

This vertical line will cut the locus of b’ and locus of b at. Mark that point b’ and b respectively.

Join a’b’ (FV) and ab (TV).

Taking a’ as center and a’b’ as radius draw an arc which will cut the horizontal line passing through a’, mark that point b2’.

Join a’b2’ (EL).

Taking a as center and ab as radius draw an arc which will cut the line passing through a, mark that point b1.

Join ab1 (PL).

Take the projection of b1 into FV (Draw a vertical line from point b1) which will cut the locus of b’. Mark that point b1’.

Join a’b1’ (TL).

Take the projection of b2’ into TV (Draw a vertical line from point b2’) which will cut the locus of b. Mark that point b2.

Join ab2 (TL).

Measure the TL and true inclinations θ and Φ.

Answers – i) TL = 77 mm

ii) θ = 27°

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