You can draw 2D circles and ellipses by using the Circle and Ellipse tools, respectively, in the Sketch menu.

Circle

Before you draw circles, choose whether you want to define circles with radii or both radii and diameters. You can do so from the Circular annotations option, reachable from the Orientation cube in the design space. 

If you're using a pen, tap Circle and then tap the grid to place the center and drag your pen until you reach the correct radius or diameter. If you want to redefine the shape’s radius or diameter, tap on the dimension label and add a value in the numpad. 

If you're using a mouse or touchpad, follow these steps: 

1. Select Circle in the Sketch tool menu. 
2. Click to add the center and circumference points. You can also type the radius or diameter to quickly define the length. 
3. Finish the sketch by pressing Enter. 
   If you want to remove the shape, then press one of the following:
   • Backspace
   • Escape
     Or, secondary click (right-click) with your mouse. 
4. Press the Escape key to drop the active sketching tool. 

When you select the drawn circle or its dimension label, you can see the radius or diameter, depending on your Circular Annotations setting.  

Ellipse

If you're using a pen, tap Ellipse and place the center of your ellipse on the grid. Drag your pen to create the shape. You can then define the major and minor axes by tapping on the dimension labels.

If you're using a mouse or touchpad, follow these steps:

1. Select Ellipse in the Sketch tool menu. 
2. Click to add the center and circumference points. 
3. Finish the sketch by pressing Enter. 
   If you want to remove the shape, then press one of the following:
   • Backspace
   • Escape
     Or, secondary click (right-click) with your mouse. 
4. Press the Escape key to drop the active sketching tool.