Isometric Circle

1. Start by drawing a isometric square. Label the corners and midpoints as shown in the illustration. |

2. Create lines between the following points: A to 1, A to 2, B to 3, B to 4. Label the intersection of the line A1 and B3, C1 and the intersection of B4 and A3, C2. |

3. C1 and C2 are the centres of the circles whose radii are C13 and C24 respectively. These circles form the curves at either end of the isometric circle. |

4. The remaining two curves are formed by larger circles. Points 1/2, and 3/4 are points on these curves respectively. |

Isometric Arc

1. In drawing round corners (quarter circles) lay off the required radius from the corner in both directions. Lightly draw lines from the determined points perpendicular to the sides of the object. Their intersection will be the centre of the quarter circle. |

2. To draw the lower arc drop a light vertical line the thickness of the object. The end of this line will be the centre of the arc. Always draw arcs or parts of a circle by eye, keeping in mind the position of the centrepoint. |