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