Sri Vidya College of Engineering & Technology, Virudhunagar
Course Material (Lecture notes)
CONSTRUCTION OF ELLIPSE:
1. Draw an ellipse when the distance between the focus and directrix is 50mm
and eccentricity is 2/3.
Draw a perpendicular line AB (directrix) and a horizontal line CE (axis).
Mark the focus point F on the axis line 50mm from the directrix.
Divide the CF in to 5 equal parts.
As per the eccentricity mark the vertex ′V′ in the second division of CF
Draw a perpendicular line from vertex V and mark the point ′G′ with the distance VF.
Join the points C& G and extend the line. Similarly mark the point G1 below the axis
Now join the points C& G1 and extend it.
Draw number of smooth vertical lines 1,2,3,4,5,6,etc., as shown in figure.
Now mark the points 1′, 2′, 3′, 4′, 5′…
Take the vertical distance of 11′ and with F as center draw an arc cutting the vertical
line 11′ above and below the axis.
Similarly draw the arcs in all the vertical lines (22′, 33′, 44′…)
Draw a smooth curve through the cutting points to get the required ellipse by free
GE 6152 - Engineering Graphics - UNIT 1
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