How do I create an animal outline using paw-prints?

[GWR71]

I have an image of a lion with alpha channel, and a paw-print. I want to create an outline of the lion using paw-prints, and animate it so the paw-prints slowly build up the outline.

I used to use Apple Motion, and to achieve this effect I'd just use a stroke with a custom brush (i.e. the paw-print) and keyframe the endpoint of the stroke, but I can't find any way to create custom brushes in AE.

Any help gratefully received!

[Mylenium]

There is no such thing as custom brushes in AE. You can try and use particle systems that follow the contours and drop a particle that stays in place every so and so many pixels. Conversely, you can create a particle grid and feed a revealing stroke from a pre-comp as a parameter map for visibility/ opacity or scale into it. Realyl depends, but in any case you need to take a different approach from Motion.

Mylenium

[GWR71]

Thanks, that's a shame. It would literally take about two minutes in Motion. Hey ho.

[Rick Gerard · Accepted solution]

When I need something that motion can do with a single click for a client that does not mind canned effects I use motion. I am in business to make money first because without money you cannot pursue your artistic goals. I would use motion, render with an alpha channel and then use it in your current production.

If you really want to create a custom brush and use it in AE you can use this technique that I posted a while ago: Re: Repeat Shape Layer along path?(Message) By Rick Gerard, posted May 28 2013