Path operations

Expression Design can combine two or more paths or shapes in various ways using path operations. These commands allow you to add or subtract shapes. For example, you could join two separate paths into one, to have one shape act like a cookie cutter on another one.

To perform a path operation on two or more selected paths, click Path Operations on the Object menu, and then click one of these commands:

• Unite  This feature combines all of the selected shapes into one object, and no hole is left behind where they overlap. If some of the original paths aren't overlapping the others, then the Union command leaves the objects separate, but they all act as one compound object. (In fact, if none of the original objects overlap, then Unite is identical to clicking Compound Object on the Object menu, and then clicking Make.)

• Front minus back  This feature acts just the opposite of Back minus front. It cuts the shape of the back-most selected object out of the front-most selected object.

• Back minus front  This feature uses the front-most selected object as a "cookie cutter" on the back object. The shape of the front object is cut out of the back-most object, even if that means punching a hole in the middle of it.

• Intersection  This feature looks for areas where the two or more selected objects overlap. It keeps those areas and deletes all the other areas of the shapes. If the front-most object does not overlap the back-most object (or if you have three or more objects that don't all overlap in the same area) you'll see an error message and the paths won't be affected.

• Divide  Like the Intersection path operation, this feature cuts the selected paths up based on where they intersect, but it leaves all the pieces (it doesn't delete the parts that don't intersect). While the other path operations result in only a single path, Divide often results in two or more separate paths or shapes.

With the exception of the Divide and Back Minus Front commands, the resulting path always takes on the fill, stroke, and effect attributes of the top-most selected object. In the case of the Back Minus Front command, the back-most object's attributes are maintained. In the case of the Divide command, each resulting object takes on an appearance based on how the segment appeared before you performed the path operation.

If you've selected three or more paths, the path operation is applied first to the first two paths, then to the newly formed path and the next path, and so on.

After a path operation, Expression Design usually deletes the original source paths. If you'd rather keep them around, you can duplicate the source objects before performing the path operation. Alternately, you can select the Path operations: keep originals option in the General page of the Options dialog box.