Step 3: Draw the 4 horizontal lines going through the intersection points. The sight rays E(M, Q, R, S, N) divide each horizontal line in four segments which in reality have the same length as the segment [MQ].
To see result click here.
Assumptions:
Point E: the position of the eye (often also called the observation point)
Line (HE): the horizont
Plane (MNOP): the picture plane
The points Q, R and S divide the basis of the canvas [MN] in 4 isometric segments.
Note: E(M, Q, R, S, N) will correspond to the five staight lines (EM), (EQ), (ER), (ES) and (EN).
Step 3: Draw the 4 horizontal lines going through the intersection points. The sight rays E(M, Q, R, S, N) divide each horizontal line in four segments which in reality have the same length as the segment [MQ].