Ai: Using the pathfinder function on appearance-expanded brush strokes.


Hi all,


This probably has an insanely obvious solution that I've missed, but humour me:

This image above shows a custom brush I have made in Illustrator (left).

The shape at the top is the graphic I used to make the brush (a simple black vector with a white vector layered over it). Underneath it are a bunch of strokes done with the brush.

What I want to be able to do, is somehow tell the pathfinder tool to punch out all areas of white (so they become transparent areas of the brush stroke). Just doing this individually to each stroke/making a brush with a transparent area will not work because the hole will just show the ugly edges of the other brush strokes underneath.

(This is what I mean by not wanting the transparency to show the brush strokes underneath).

The result needs to look like the green-ticked image on the right. (Note how only the 'visible' areas have of white have been punched out, unlike the example in the middle.) This matters because brush strokes in question are going to be heavily repeated/layered on top of each other.

The end result will hopefully allow me to take the black areas of all of the piled up brush strokes and merge them into one vector with the pathfinder tool after the white areas have been cut out.

I am hoping that the solution will be able to be done en masse, via the select > same > fill colour menu options when applying whatever change I need to make to the white areas (the image I am working on will contain thousands of tiny brush strokes, so individually weeding out the white areas would be a nightmare).

Any ideas?

Thanks in advance...


Paul Murray

Staff member
I just had a go at recreating this and the 'Trim' button in the pathfinder window gave me the desired result.

Screen Shot 2016-12-01 at 11.38.58.png Screen Shot 2016-12-01 at 11.38.03.png
From here you should be able to select the outer edges and join them together with the 'Unite' option.



10 points to Slytherin (I assume that's where the Hogwarts Graphic Design campus is).

It works! I've been trying varying different combinations from the pathfinder for ages - just needed a fresh pair of eyes.

Cheers Paul!