|Turning Paint Into Masks in After Effects|
Paint strokes and masks are both versatile tools in After Effects, but sometimes you may find you've used one when you should have used the other. Fortunately, both features are based on vector paths, although going from the Vector Paint effect to a mask isn't the most straightforward procedure. In this tutorial we'll walk through that process, and we'll also show how much easier it is to do with AE6's new Paint tools. Finally, we'll look at an alternate method of getting a mask from your paint strokes by using AE6's Auto-Trace feature. It's a little rougher, but the potential time savings are enormous.
Start by opening on the Paint_to_Mask.aep project file. Look at the Bessy Roto - Start comp. Here we have Ol' Bessy in front of her barn. We want to isolate just Bessy's head without the background or the text of the logo. I've started rotoscoping her out using the eraser brush in Vector Paint, but have very quickly realized that using a mask will be faster. Rather than start the mask from scratch, what we're going to do is take that paint stroke and convert it into a mask. Start by opening the effects for the Bessy layer and selecting the Vector Paint effect. The Vector Paint tools will appear on left hand side of the comp window.
We've accomplished our goal. The paint stroke has been transformed into a mask, and now Bessy is rotoscoped out of her logo. A little cleanup will make Bessy look prettier, though. Delete the adjustment layer and turn off the Vector Paint effect. I tweaked the mask feather and expansion properties to give Bessy a smoother edge. Then I added a drop shadow, animated the position and rotation properties, and gave Bessy a little dialogue. Preview the Bessy Roto - Final comp to see the results. Ta da!
If your project involves a lot of Vector Paint work, it's clear that converting all of the paint strokes to masks could be a time consuming process. AE only allows you to copy one paint stroke at a time. After Effects 6.0 has two new tools that can make the process a lot easier: the new Paint effect and the Auto-Trace command.
Turning paint strokes into masks is far less complicated when you start with AE6's new Paint effect. It's just a matter of copying the paint stroke shape to the mask shape. Note that I said "start with"- there's no easy way to convert Vector Paint strokes into the new Paint strokes, other than turning them into masks and copying those into Paint. So plan ahead. The new Paint tools are worth the time to learn.
Open the Paint Roto - Start comp. This is identical to the Bessy Roto comp, except that the roto painting has been done using the eraser tool of the new After Effects 6.0 Paint effect instead of Vector Paint.
Just like with the Vector Paint instructions, a little cleanup work is desirable. Turn off the visibility of the Paint effect (or just delete it), and adjust the mask feather and expansion to clean up the edges. I also added some text and a couple of drop shadows. Preview the Paint Roto - Final comp for the result.
It's worth mentioning that not only can Paint strokes be copied into masks, but masks can be copied into Paint strokes (something that can't be done with Vector Paint). To do so, just reverse the process: copy the Mask Shape, draw a paint stroke, and paste into the stroke's Shape property. If you want to use the mask to roto-paint, make sure you draw your stroke with the eraser tool. (TIP: You can also convert any existing paint stroke to an eraser stroke by changing the color to 100% black and the Channels property to Alpha.)
Converting paint strokes into masks can be tiresome if you have a lot of strokes. What if you don't have the time or patience? There is a quick and dirty alternative to have AE6 make a mask out of paint strokes for you: the Auto-trace feature. The difference is that instead of using the vector path of the paint stroke, Auto-trace creates the mask from of the outline of your paint strokes.
Open the Speed Bessy - Start comp and preview it. Here's Bessy, happily zooming around the barnyard. I've added a Vector Paint stroke as a cartoon speed trail. It's kind of cheesy looking. With the help of Auto-Trace, let's turn it into a smoke trail instead.
Presto! Bessy is now burning rubber, er, pixels across the countryside. Preview the Speed Bessy - Final comp to see the results.
In this example, I started with the Vector Paint effect. If you were to start with AE6's new Paint effect instead, the process requires only a single adaptation: In step 1, open the Paint effect settings and switch the Paint on Transparent property to On.
Practical application of using Auto-trace with your own comps may vary in difficulty. Most likely you'll need to play with the tolerance and threshold values in the Auto-trace dialog to get an accurate mask, especially when dealing with airbrushed or feathered paint strokes.
We've covered a lot of detail about paint strokes and masks. Let's run through the important points one more time:
If you found this page from a direct link, please visit our forums or read other articles at CreativeCOW.net