How to draw an Ellipse

By: Tim Closs

What is an ellipse?

• Basically it is a stretched circle

What is an Axis?The horizontal line and vertical that pass through the center.

What is the Minor Axis?The shortest axis. Which in this case is the vertical line.

What is the Major Axis?The longest of the two axis. Which is the horizontal line.

Tools you will need

• 45/90 Triangle or 30/60 Triangle

• A piece of computer paper

• T-Square or parallel with drafting board

• Masking Tape

• Pencil with eraser

• Compass

Step 1

• Line up paper with T-square parallel

Step 2

• Tape down Top corners

Step 3

• Tape down Bottom corners

Step 4

• Find the Center of your paper using the cross technique (see last weeks notes)

Step 5

Layout vertical axis using :• 45/90 Triangle

• T-square

• Pencil

Step 6

Layout horizontal axis using :• T-square

• Pencil

Step 7

Mark Minor Axis

• Set compass to aproximatley 2 inches

• Mark vertical axis

Step 8

Mark Major Axis

• Set compass to aproximatley 3 1/2 inches

• Mark horizontal axis

Step 9

• Mark center O

• Mark major axis A B

• Mark minor axis C D

Step 10

• Set compass from O to C

• Make a mark on the right side of major axis

• Label E

Step 11

• Using your triangle draw a Line from C to B

Step 12

• Set compass to E B

• Set compass on C and swing an arc intersecting line C B

Step 13

• Label intersection F

Step 14

• Bisect line F B (see earlier lessons on bisecting a line)

Step 15

• Extend Bisector to make point H

Step 16

• Mark point G where bisector intersected line AOB

Step 17

• Set compass O to H

• From O make a mark above C and label it K

Step 18

• Set compass O to G

• From O make a mark to the right A and label it J

Step 19

• Using your triangle draw a Line from H through J

Step 20

• Using your triangle draw a Line from K through J

Step 21

• Using your triangle draw a Line from K through G

Tangency

• Line K J

• Line H J

• Line K G

• Line H G

Step 22

• Set compass to G B

• Having the center on G swing an arc to both Tangency lines

Step 23

• Set compass to J A

• Having the center on J swing an arc to both Tangency lines

Step 24

• Set compass to H C

• Having the center on H swing an arc to both Tangency lines

Step 25

• Set compass to K D

• Having the center on K swing an arc to both Tangency lines

Reference

Walker, John and Bernard D. Mathis. Exploring Drafting. Illinois: The Goodheart-Willcox Company, 2012. Print

Photos: Taken by T. Closs