How to cut a hole that is part of a compound path

Question

I have spent many hours using all the tools available in Illustrator CS4 to reshape the hole that is part of a compound path with no success.
The compound path consists of a square with a round hole, I want to for example, cut the round hole in half. Erase, Knife, Pathfinder do not work. I can do it if first release the compound path, cut the round hole, then make compound path again. While this method is easy for this example but not good for very complex drawing, because it would be too time consuming to convert back and forth the compound paths and remembering which holes belong to which compound path. Please help. I am to the point where I am willing to spend money to get a good cutting tool plugin, any reccomendation?

Answer 1

Sure....
Place or Open raster image.
Live trace (whatever settings you like) I'm assuming it's a 1 color trace (line art) and not a photo or color image
Click the "Expand" button in the Control bar
Everything should be selected/highlighted
Click the Merge button on the Pathfinder Panel (3rd from left, bottom row)
*optional -- Choose Object > Ungroup from the menu (Using Pathfinder command creates Groups for some reason. These groups aren't always needed.)
Deselect all (Command-Shift-A or Ctrl-Shift-A or just click somewhere empty to deselect the artwork)
Select the Direct Selection Tool (the white arrow)
Click the center of a "hole" or counter. This will select one of the superfluous white shapes.
Choose Select > Same > Fill & Stroke from the menu. All the extra shapes should highlight.
Hit delete.
You should be left with just black compound paths with no superfluous shapes anywhere. In fact, after this if you Select All, the color panel shoudl show a simple black fill and no stroke. Of course, this somewhat depends upon your Live trace settings.
What this does is merge all black and white shapes into the simplest form and at the same time it cuts through bottom objects with top objects. So if you have a white shape sitting on top of a black shape, it cuts that white shape out of the black. This ensures all the black has the correct compound shape assignments. Sometimes with Live Trace you can get white fill areas and not get the corresponding compound hole below it. Or the compound hole will not be exactly the same shape as the white object sitting on top of it. Using Merge corrects that. Then deleting the white shapes just removes all the unnecessary objects. If you want a color for the compound holes, just draw a rectangle or shape below the black and fill it with any color. All you need to is alter the counters or compound holes now to correct anything. No more double paths.
All these steps are not always necessary. But it's sometimes good practice depending upon what you are tracing. Once you do it once or twice you'll see it's only about a 1-2 minute processes and most of that will be waiting for the Merge command to complete.