If you are drawing on isometric planes to simulate three dimensions, you can use ellipses to represent circles viewed from an oblique angle. First you need to turn on an isometric plane (see “Setting Snap and Grid to Isometric Mode“).
To draw an isometric circle
- Turn on the Isometric snap and grid. ( If you forgot, see link above and review)
- From the Draw menu, choose Ellipse Axis, End. Then AutoCAD wil prompt: Specify axis endpoint of ellipse or [Arc/Center/Isocircle]:
- Enter i ( or type the word “Isocircle”) then press enter.
- Then AutoCAD will prompt again: Specify center of the isocircle. Which asking you to specify the center of the circle (See Fig. 1). It could be any place in the drawing area of the AutoCAD interface. Click then press enter.
- Then another prompt will show up: Specify radius of isocircle or [Diameter]: Then specify the radius by typing a value or if you want to input the diameter of the circle, type “D” first then wait for another prompt that will say: Specify the diameter of isocircle: then put the value of the diameter and press enter.
Fig. 1 – Drawing an Isocircle