Hello, this is the tutorial using opacity mask, like the title said. Using this mask, you could have a more complicated mask , and I think this is an awesome trick to learn. Let’s get it done then….

Step01:
Make box using rectangle tool(M), then go to window>swatch library>gradients>sky. Fill it without any stroke.  And we just made our base color.

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Step02:
Next, go to window>symbol>grime vector pack. Select symbol sprayer tool (shift+S) and then spray it once.

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Step03:
Select the sprayed item, go to object>expand. Click ok.

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And then recolor it into white. Drag it into the symbol box(shift+ctrl+F11).Name it anything you want.

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Step04:
Now back to our base color. Go to transparency box (shift+ctrl+F10). Click the drop down icon, select make opacity mask. It should look like this now.

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Step05:
Activate the black one, select symbol sprayer tool (shift+S), and choose the one we just made.

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Spray it a couple of times.  You could get a variation using other symbol tool.

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Step06:
Then go to object>expand, then click break link in the group box.

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Step07:
Select twirl tool in the tool box. Start twirl it, until you like the result. This is how mine’s look like.

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I know it just a short tutorial but using this method and the radiance method I could get result like this.

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