Here a couple methods you could try. Copy the path in illustrator, add a solid above your vector graphic, add the Generate > Write On effect, click the brush position stop watch and cntl+v the illustrator path to the brush position. Change the Brush Time Properties to “Size”, and then you can keyframe the brush width, to the irregular sizes you need. Now just change your vector art to alpha matte. One drawback to this method, is you either need to adjust your illustrator artwork to be the same comp size in AE, or will have to make adjustments in AE to get the paths to match up.
2nd idea would be to use the motion sketch tool. Create a solid, turn off the visibility and do a motion sketch capture, tracking your artwork. Now you can copy those positions keyframes into the brush property of write on effect. Select all the keyframes, right-click and you can turn them into “Rove Across Time” keyframes. And you have the ability to keyframe the stroke width.
Johnny Cuevas, Editor
Thinkck.com
“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.