Example of Alteration of Reference Line Method:
A right regular hexagonal pyramid 80 millimeter in height and side of base 35 millimeter, having an edge of the base in HP and the face having that edge is inclined at 47o to HP. Sketch its projection.
(a) Sketch the hexagonal plan 1, 2, 3, 4, 5, 6 along with side 35 millimeter and one side of base 1, 6 is perpendicular to VP.
(b) Complete elevation along with base in HP and axis of such pyramid perpendicular to HP and parallel to VP.
(c) To receive the final plan via alternation of reference line method Sketch another reference line X1 Y1 passing via point 1′ and 6′ at an angle of 47o along with 1′ O′ or like slant edge of pyramid.
Note: X1Y1 is intersection of VP and auxiliary HP on that plan is to be drawn.
(d) Sketch projections from various points in elevation that are perpendicular lines to X1 Y1.
(e) Get the distance of points 1, 2, 3, 4, 5, 6 and O from XY and mark 11, 21, 31, 41, 51, 61 and O1 on respective projectors that are perpendicular to X1 Y1 as an example to situate point 11, distance 1′ 11 is equal to 1′ 1.
(f) Sketch hexagonal base via joining 11 21 31 41 51 61 is like visible and connect O111, O121, O161, O151 by dark line is like visible and O131 and O141 via dotted line is like not visible and complete the plan.