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ironpony
03-26-2012, 12:51 AM
I shot a scene for a short film. The actress has blood on her face, but then somehow it's gone. I don't know what happened while shooting as it was close to the last few shots, and I must have not have noticed that the blood somehow disappeared. The shots came out a little too dark and needed to be tweaked, so I just noticed that now after quite a while. Is it possible to rotoscope the blood off the side of her face, and put it on her face in the other shots? The only thing is, she turns her head in newer positions and makes newer faces, so the shape of the blood would constantly change and I need to make those changes. Do I have to do this frame by frame, or is there does the rotoscoping automatic features take care of this and can go frame by frame for you and put in the changes by itself? I was told it can for some things but not sure about this problem, and am still figuring it out. I have CS5.5. Can I keep the blood attached to her face, and it will move as she moves? What can I do? Thanks.

arco1
03-26-2012, 06:02 AM
"Can After Effects do this?" The answer is "yes probably, given a highly-skilled AE person and/or a lot of time...."

There is really no automatic rotoscoping tool to do what you propose. You'd need to find a way to adjust the "blood" to match each frame as she turns her head, changes expression, subtle lighting changes, etc. Certainly not something I'd recommend for a first-project in After Effects. If it were just a few frames that needed the change, it might be worth the time/effort to do the work in AE (or even Photoshop), but it sounds like you might have many seconds of footage.

You are likely to find it easier/cheaper to re-shoot than to convincingly change your existing footage. Or perhaps you could darken the existing footage so that her face is in deep shadow and re-shoot just a few closeups (with blood) that are less shadowed.

Jim

WhiteMonkey
03-26-2012, 06:27 AM
reshoot.

daihard
03-26-2012, 06:55 AM
Aye... best is to reshoot.
You can make nodes, and probably have it track for most normal movements. But face expressions, lighting, and loads of other movement/interaction... it's just gonna end up coming out too CG looking. Best to reshot, or rethink your edits... maybe focus on fine details rather then her entire face for a few scenes.

Hawk Teflon
03-26-2012, 08:35 AM
I'll third that reshoot. Unless it's impossible (not to be read "inconvenient"), reshoot it. This will be a time consuming PITA that you'll probably be settling for the results.

ironpony
03-26-2012, 04:34 PM
I can't reshoot. I didn't notice this until after I fixed the footage. Some of the shots were too dark, once the actress got into a certain room, so I had to fix those images. Now that they are fixed the blood is noticeably gone. But it's been too long now, and the actress has completely changed her hair for another gig. After that she is moving. I do have some other shots of her which I did not use though, and I can use the blood on those shots, from when she is making similar faces at similar angles. Hopefully that might work.

Todd_Kopriva
03-26-2012, 11:29 PM
If you can't reshoot, then using moton tracking and compositing techniques like those described here can work:
http://www.mamoworld.com/index.php?option=com_content&view=article&id=82%3Atutorial-cyborg-arm&catid=35%3Atutorials&Itemid=62&lang=en

arco1
03-27-2012, 04:59 AM
In addition to Todd's excellent recommendation: A few years ago, Pistol Youth did a music video "In My Eyes" spoofing the opening to the Golden Girls television show. They replaced the ladies' faces with faces of band members. There are several 'how it was done' videos out there to give you some idea just how difficult it will be to replace a face in an existing video. To start try
http://www.imagineersystems.com/videos/pistol-youth-in-my-eyes

Todd_Kopriva
03-27-2012, 08:10 AM
Here's a writeup on my blog about the face replacement techniques in the video mentioned by arco1:
http://blogs.adobe.com/toddkopriva/2009/04/face-replacement-with-mocha-fr.html