Projection of Lines

 SAMPLE PROBLEM 1 : Line AB 75 mm long makes 45o inclination with Vp while it’s Fv makes 55o . End A is 10 mm above Hp and 15 mm in front of Vp. If line is in 1st quadrant draw it’s projections and find it’s inclination with Hp.

Steps for projection of lines :

Step 1. Draw x-y line. Draw one projector for a’ & a Locate a’ 10 mm above x-y & Tv a 15 mm below xy.

Step 2. Draw a line 45o inclined to xy from point a and cut TL 75 mm on it and name that point b1 Draw locus from point b1 .

Step 3. Take 55o from a’ for Fv above xy line. Draw a vertical line from b1 up to locus of a and name it 1. It is horizontal component of TL & is LFV.

Step 4. Continue it to locus of a’ and rotate upward up to the line of Fv and name it b’.This a’ b’ line is Fv.

Step 5. Drop a projector from b’ on locus from point b1 and name intersecting point b. Line a b is Tv of line AB. Draw locus from b’ and from a’ with TL distance cut point b1

Step 6. Join a’ b1’ as TL and measure it’s angle at a’. It will be true angle of line with HP

SAMPLE PROBLEM 2 : Fv of line AB is 50o inclined to xy and measures 55 mm long while it’s Tv is 60oinclined to xy line. If end A is 10 mm above Hp and 15 mm in front of Vp, draw it’s projections,find TL, inclinations of line with Hp & Vp.

Steps for projection of lines :

Step 1. Draw xy line and one projector. Locate a’ 10 mm above xy and a 15 mm below xy line.

Step 2. Draw locus from these points.

Step 3. Draw Fv 50o to xy from a’ and mark b’ cutting 55 mm on it. Similarly draw Tv of 60o to xy from a & drawing projector from b’ Locate point b and join a b.

Step 4. Then rotating views as shown, locate True Lengths ab1 & a’b1’ and their angles with Hp and Vp.

Video materials for Projection of Lines