Isometric Circle using the Ordinate Method Drawing Abilities Teacher Isometric Circle using the Ordinate Method © J Lewis 2004

Drawing the Orthographic Circle Draw a circle to a required diameter with centre lines A – A and B - B © J Lewis 2004

Dividing up the Diameter Divide the diameter A – A into a suitable number of equally spaced parts ( 8 in this example ) © J Lewis 2004

Drawing Ordinates Number the points as shown and draw Ordinates ( Verticals ) parallel to B – B through these points. © J Lewis 2004

Drawing the Isometric Square Draw an Isometric Square with each side the same size as the diameter of the circle. Draw A – A and B – B as the horizontal and vertical centre lines. © J Lewis 2004

Drawing Ordinates Divide the horizontal centre line into the same number of spaces as you previously did for the circle. © J Lewis 2004

Drawing Ordinates Draw Ordinates ( Verticals ) through the points on the centre line and number as shown. © J Lewis 2004

Transferring measurements The length of each ordinate, above and below the centre line A – A, is transferred from the circle to the isometric square. © J Lewis 2004

Completing the Isometric Circle The points at the ends of these lengths are then joined by a smooth curve to form the isometric circle. Notice that the centre line B – B could also have been used to generate the circle ordinates. In using this method, a few accurate ordinates are better than many drawn inaccurately. © J Lewis 2004