Case 4. Line perpendicular to HP & parallel to VP
A line AB of length 80 mm is parallel to VP and perpendicular to HP. The line is 80 mm in front of VP and 80 mm in front of right PP. The lower end of the line is 30 mm above HP. The projections of line AB shown in figure 4 can be obtained by the following method.
Draw a line XY which is the intersection between VP and HP. Draw the front view a'b' = 80 mm perpendicular to the XY line, with the lower end b' lying 30 mm above the XY line. Project the top view of the line which will be a point a(b) at a distance of 60 mm below XY line. Since the line is 70 mm in front of the right PP draw the X1Y1 line at a distance of 70 mm on the right- side of the front view.
Through O the point of intersection of XY and X1Y1, lines draw a 45° line. Draw the horizontal projector through a(b) to cut the 45 degree line at m. Draw the horizontal projectors through a' and b' to intersect the vertical projector drawn through m at a΄΄ and b΄΄. a΄΄b΄΄ is the left view of the line AB.
Figure 4. Projections of a line AB perpendicular to HP and parallel to VP.