Cut an illustrator image in half?

I have a largish illustrator image on multiple layers.

By "Illustrator image", I'm going to assume you're not talking about a raster image, but about a typical illustration composed of many vector paths, some closed, some open, some filled, some not filled.

In essence I want to cut it cleanly into 3 peices for different files. Is there an easy way to do this?

Not in Illustrator, because Illustrator has never had and still does not have a decent tool for cutting its own artwork. It now has no less than THREE separate cutting tools and they are all pure junk compared to common functions in other drawing programs:

• The Scissor requires you to tedously cut one path at a time.
• The Knife does provide a keyboard shortcut to constrain it to straight cuts; but it stupidly fails to cut unfilled open paths.
• The Eraser should be the closest for your need, but it always cuts a swath, not a zero-width cut, and it unpredictably distorts the remaining segments. If your artwork is such that the resulting distortions do not wreck it, that would be the simplest method that AI provides. Work on a copy of the file. Collect all the artwork in a Layer. Duplicate that Layer. Draw guides

I could do masks for three areas I suppose…

That long ago became the Illustrator-user default workaround, because of the program's lack of such a no-brainer standard feature as a straighforward cutting tool. It has so long been resorted to by AI users, that most of them have forgotten that it is, in fact, a workaround.

but the image is very large and its a bit of a waste.

Yep. Understand. Illustrator is full of inefficient habits, due to its functional limitations.

Ideally I want to keep the vectors so photoshop might not help.

Rasterization: The other workaround too often resorted to.

You don't say what version. ALWAYS state what version you are using.

Another workaround is using page tiling (CS3) or artboards (CS4) to export PDF pages that effectively "split" your artwork. But that also fails to actually cut objects which cross the trims, and masks the outboard portions. (Less wasteful than containing and masking objects that are entirely outside the trim, but still nothing anyone would call tidy.)

JET

Garethi,

It depends on the artwork. I presume it is vector, not raster.

1) If you have closed paths, you may create a rectangle on top enclosing the middle part, with sides where you want the cut and extended the other way, and with that selected Object>Path>Divide Objects Below. You may need to use the Scssors Tool to remove parts of stroked paths along the division.

2) If you have open paths, you may place the division line beneath them and cut at the intesections with the Scissors Tool.

You may use a combination of 1) and 2), and other solutions may be better/relevant, depending.

Smart Guides are your friends.