A big hit inside of Adobe After Effects is the Roto Brush. It does a great job of simplifying and rotoscoping an object. The Roto Brush takes away some of the more time consuming steps and allows you to then go in and refine the results that you get. In this video, instructor Richard Harrington walks you through how to rotoscope with the Roto Brush in After Effects.
- Sometimes you're going to have footage that you want to erase away things selectively. Now of course, you can use masks and other tools to do this, but it's not the same as using a pixel based tool. Fortunately After Effects has the rotobrush, which allows you to essentially rotoscope or cut out parts of a subject. Let's do this to change a background in a scene. I'll drag the shot into After Effects and let's right click to create a new comp from selection.
oom out a little bit and you see our subject. What I'd like to do is remove him from his background. Now, normally this would be a lot easier if you shot something green screen, but sometimes after the fact, you want to make a tweak. I can do that here. Lets duplicate the footage layer and turn the background copy off. What I'm going to do is double-click to open up the layer and I'll choose the rotobrush, it's right here.
Make sure you do this on the layer itself and drag to add some green strokes on the subject. You don't have to do right up to the edge, but you should try and get most of the key details. Then holding down the option or ALT key, you can drag to put some strokes on the background area, defining what's the background.
If something gets missed, you can click to add a little more and you can see as you do that, that starts to find the edges. That worked well. You might want to consider clicking, to see your different views. For example, you can view as a black and white matte, take a look at a ruby lit mask, or see edges or black. Let's go ahead and set this over transparent pixels there. I'd like you to really get a pretty good idea of what's happening.
Now, if you take a look at that, it didn't do a bad job of cutting things out. Now, you see it did a pretty good job of extracting that from the background, but what I want to do is take advantage of a couple of choices. In this case, I'm happy with the extraction, but you'll notice that it doesn't apply to the entire clip. Lets press "e" to see the effect and take a look at the rotobrush. Mousing over the timeline, I'll press the accent grave key or tilde and I'm just looking at what's happening there.
I see the effect and what we really need to pay attention to is a smaller setting, so lets back out and look really close here at the timeline. It's a little bit difficult to see, but there's a small area here that you need to adjust. What happens is, is as you drag through, the effect only applies for about two seconds at a time. It's very subtle, but there's a small gray area here, you might see the segments. Let me adjust the interface color here for a moment, and I'll make the interface a little bit brighter and you might better see the segments there.
This controls the rotobrush area, by default it's usually about two seconds in duration. You might find it necessary to drag that out to match the duration that you need, so it covers the whole clip. Now, if you take a look at that and we move through, it looks pretty good. I suggest you move the play head through and if you notice any parts of the shot where the person doesn't look correctly cut out, remember you can click to add additional strokes. You can add or subtract using the ALT key or option key, but I find that by just clicking every second or so, I can audition the clip.
This looks pretty good here, so I think it's ready to move on to refinement.
- The retoucher's toolbox: cloning and healing tools
- Stabilizing footage
- Fixing alignment
- Retiming footage
- Removing lens distortion
- Using rotoscoping to enhance footage
- Recovering exposure
- Color grading with Photoshop
- Converting to black and white
- Creating a film look