The 'Circle' tool is used to create 2 dimensional circles. Select the tool and left click the mouse anywhere on the screen, that becomes the center of the circle. Move the mouse and click again to define the radius. You will notice as you move the mouse after defining the center of the circle you will see the circle drawn in either red, green or blue, depending on which axis the circle is being drawn on (remember the earlier section about color coded axis).
The 'Arc' tool is used to create an arc of a circle. Select the tool and left click anywhere. This point is the first point of the line that defines the section of the arc. Clicking again defines the line, now move your mouse anywhere and you will see an arc drawn between the two ends of the line that you had drawn. Notice the inference lines as you move the mouse around before clicking the final point. It is once again coded red, green or blue to indicate which axis the arc is being drawn on.
To make these 3D objects use the 'Push/Pull' tool. Using the 'Push/Pull' tool on a circle makes it a column.
In the case of an arc, you will notice after completion that the arc does not create a surface. You must do this by creating a line between the two ends of the arc. Once the surface has been created you can use the 'Push/Pull' tool on it. It creates a sectional column, or a column that looks like it has been sliced vertically.
We will take a more in depth look at curved surfaces in the advanced modeling section.
