Im trying to make a graffiti like animation of an object being sprayed on.
But the pen tool is not wide enough as a stroke tool, and i cant figure out how to use the brush tool to reveal my image?
In that effect, it's like there is a stencil where the paint is going on, but the following technique would work in either case.
Create your object, text and place it in a comp over your background. Create a solid and call it paint. Double click your layer to open up the layer window and select the brush tool. In my example I used a brush with 600px diameter, 10 Angle, 45% Roundness and Spacing 62%. Now paint the layer where you want the spray paint to go. It took me a few attempts to get the start correct, but eventually I was able to create one paint stroke that covered my entire text.
----If you really wanted to make this easy, you could take your object and background and prerender them, re-import them and paint that layer and use it as a track matte for your solid color. that way you would know exactly where you were painting in the layer window.
Finally, open up the paint effect and turn on "Paint on Transparent" and animate the Brush -> Stroke Options -> End %
To create a look like in the video you linked, you would place your object as the top layer in the layer stack and your paint below it and change the paints track matte to alpha inverted.
To paint on the object, Paint is the top, object in the middle and the track matte would be alpha.
"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.