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Tutorial Rotoscoping: fix goofs, change virtual sets, or make your hero fly

Click here to view the tutorial video for Rotoscoping.

Rotoscoping is one of my favorite things in Visual FX. I know that sounds crazy, but the results of rotoscoping can be so rewarding. Doing the actual work can be tedious, but, when it's all said and done, you can sit back and be proud of your accomplishments.

What is rotoscoping? Here's the simple version: rotoscoping is articulating a mask to either add something to or remove something from the frame. You do this process frame by frame, and that's why it's so tedious and time-consuming.

This article is not just a step-by-step guide. It's actually more about sparking ideas on how you can use rotoscoping and masking in order to make your films better by increasing your production value. There will be two examples provided. If you would like to see more, visit the video tutorial section at www.videomaker.com, where we aren't limited by word count and page space.

We used Adobe's After Effects, your software tips may vary. Remember, rotoscoping can cover a broad range of effects. I hope to show you some cool ones in this article.

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Have you ever had a shot ruined because the mic dipped into frame? What if you can't get the mic close enough to get good sound?

Well, think about this for a second. Maybe you can lock the shot off (no tilting, panning, zooming, dollying, etc.) and get the mic closer by actually sticking it in the frame. I don't recommend doing this for every shot, but for special circumstances, it can help.

Notice the mic in the frame of the photo.

If you must shoot your scene with the mic in the frame, take care to not overlap the mic and the actor. You also want to make sure you don't move the camera or zoom at all. Keep the lighting the same as well. This is crucial to matching the cutout section with the rest of the footage.

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Notice the mic is no longer in the shot, but nothing else has changed. The lighting, camera position, lens, etc., have all stayed the same. Removing the mic reveals the wall behind it. You'll use that section to fill in the blank area that we will cut out. This type of footage is usually called the clean plate, and that's what we'll call this footage from here on. Although I didn't do it in this example, it is best to move the actor out of the frame too.

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Using the Pen Tool in After Effects, cut out the section of the frame where the mic can be seen. Depending on the movement of the mic, you may have to animate or change the position of the mask. (You animate the mask by pressing MM on the keyboard to bring up the mask properties. Set a keyframe for the Mask Path, then move to the next frame, and change the position of the mask or mask points. This will automatically set another keyframe under the Mask Path.)

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Depending on your shot, you may have to feather the mask a few pixels. Make sure your mask is also set to Subtract. This will subtract the portion of the image you just cut out. The default is Add, which means it keeps the portion you selected and removes the rest of the image - so make sure you select Subtract.

Notice the section of the frame is now missing! Don't fret!