Expert: Amy - 9/30/2006

Question
Hello,

I'm quite comfortable with using Photoshop and trying to learn
Illustrator. My problem is quite complicated to explain but I'll try
my best. I'm using Illustrator CS2 for Mac.

I've created a basic circle shape and then added a white line
diagionally to create a cut-out effect and essentially creating the
illusion of two half circles. This works perfect when I use the
image on a white background but as soon I use a different
colour you'll see the lines as white and not as transparents cut
outs. I want the lines to cookie-cut into the shape and make the
lines transparent knockouts in the shape.

To compare it with what I'd do in photoshop: In photoshop I'd
select the outline of the line then select the layer of the shape I
want the line to cut out and then hit cmd-x (cut, clear)

I could put a few examples online to make this more clear. I'm
not sure if my problem is understandable now.

Thanks in advance,

Marijn


Answer
Hi Marijn,

I think I understand the question.

Create your circle. Give it a fill and no stroke.

When you select it, you can see that it has four anchor points.  

De-select the circle.

Using the pen tool, create a line that bisects the circle and goes through both the top anchor point and the bottom anchor point.  The line can overextend the border of the circle. But be as exact as you can in cutting the circle in half.

Then give the line you just created a stroke of 8pt.  It doesn't matter what color.

Then, with the line selected, choose Object > Path > Outline Stroke.  The line will turn into a rectangle. Again, don't pay attention to the color.

Open the Pathfinder palette (Window > Show Pathfinder)

Select both the circle and the rectangle. Choose the "Minus Front" button from the pathfinder palette.

The circle will split into two sections.

Note: The version I use is older than the version you probably use - you might have to look around for the right pathfinder button.  I heard they changed the names of some of the functions.

Hope this helped
Amy