I'm working on a complex map graphic in Illustrator that includes hundreds of layers, compound paths, etc. I want to create a clipping mask out of a rectangular portion of this map, but when I do the usual Object > Clipping Mask > Make, one of the compound paths goes all screwy. Is there a workaround for this? I've included before/after screenshots so you can see the problemo. The grey features (walls) seem to spill out some of their fills after the mask is made! Curiously, other compound features were unaffected.Before/After shot

  • I don't see anything that I'd call "distortion". You seem to have some open paths which have a fill. Perhaps convert them to outlines using Expand Appearance first. It's hard to give you a definitive answer without access to the file and how it is constructed.
    – Billy Kerr
    Sep 20, 2020 at 20:55
  • I know it's not answering the question, but have you considered if you even need a clipping mask? Instead you could just adjust the artboard to the wanted size and place the file in another document if needed.
    – Wolff
    Sep 20, 2020 at 21:41
  • Perhaps its not actually broken? What if its just the GPU renderer that glitches out? Try CPU rendering.
    – joojaa
    Sep 21, 2020 at 5:03

1 Answer 1


Very odd. Assuming those grey shapes are closed shapes, my inclination would be a bug. (Which is honestly rare for me to think.) Without more detail regarding the construction of the problem shapes, that's the best I can come up with unfortunately. If those problem shapes are indeed open paths you need to close them.

Just a thought....

When working with complex multi-layered files I find Clipping Masks at the layer level work best. However, you can only have one of these per layer, unlike the standard clipping masks.

  • Create a new Layer at the top of the stack
  • Draw a shape/rectangle to define the area to clip.
  • With the rectangle selected, from the Layer Panel Menu choose Make Clipping Mask.
    This is the only way to create a layer-based clipping mask.
  • Move all other layers below the new clipping mask in this new layer as sub-layers.

This method has some benefits and drawback though. It does allow you to essentially keep your layer structure in tact as sublayers, unlike a standard clipping mask which combines everything to a single layer. But this can make copying/duplicating those sub-layers problematic (see link below). In addition, you only need one mask to clip multiple things rather than possibly multiple masks. But, you can only use this once per layer.

More detail regarding layer-based v object-based clipping masks can be found here: Copying an artboard with a clipping mask

  • Yes!! Layer-based clipping mask works. And when I export to tiff, the export "clips" to the right area. Drawback: Client prefers vector PDF, and while an object-based clip can be exported as object-only, it appears that layer-based can't. So I'll probably try what Wolff suggested with the artboard. You guys rock!
    – CSyrett
    Sep 20, 2020 at 21:52
  • Oops....not so fast. The exported tiff and pdf recreate the original problem. Looks like resizing the artboard is the way to go.
    – CSyrett
    Sep 20, 2020 at 22:00

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