Illustrator open a side of a circle

[Rixwel]

Am drawing an image with the help of Adobe photoshop maker, I wanted to draw Circle at the left table of adobe illustrator, it only offer to draw a esclipse shape. how do i draw a round circle? Does anyone come across like this before..Please help.

[DllD]

Illustrator CS and CS2 have a 3D Effects filter. These effects can be found on the Effect > 3D submenu, and there are three to choose from. Press Command + D (Mac) or Ctrl + D (Windows) to create a row of 20 squares. As in Step 2, press Option or Alt to duplicate the row. Press Command/Ctrl + D until you've created a 20-by-20 set of gray squares. Which you choose depends on the effect you want:

• The 3D Extrude and Bevel filter makes three dimensional shapes from flat shapes.
• 3D Revolve spins a path in a circular direction around the vertical axis of a path.
• Use the Selection Tool and the Shift key to randomly select a handful of gray squares scattered around the grid.
• 3D Rotate alters the perspective of a 2D object in three dimensional space, like rotating a piece of paper to look as if it is lying on a table.

[Khushal]

This is an easy one! Just select the circle tool and hold down the Shift key when the mouse is also depressed. Now use the Direct Selection Tool (white arrow) to select the point on the right side of that circle and drag it out to the right. This will create a perfect circle. The shift key can also be used with other tools to create say, a perfect square, a perfectly straight line and many other equally perfect shapes. Select the Convert Achor Point tool and click on the achor point you dragged to get rid of the handle bars and make it a sharp corner.

[GANGSTA]

Use the Circle Tool to draw a circle. Then draw a vertical rectangle that is larger than the circle. Move the rectangle over the circle so the long side bisects the circle through the middle. Create a new layer and alt click in the center of the circle. Set the circle to 3.8 again. Turn off the fill and Turn on the stroke. Select your shape with the Selection Tool (black arrow), and in the “Brushes” palette, click on the arrow in the upper right. Select “New Brush.” A solid or hollow appearance can be made by capping or uncapping the extruded object. The Position menu has presets you can choose, or you can click and drag the cube to rotate your object, or type in angles in the boxes.