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How to replace this green screen?
Doing some test shots for an upcoming shoot and trying to figure out how I’ll pull this off in AE.
What I ultimately need to do is replace the green screen with a video. But I’m having trouble narrowing down how to replace the footage effectively.
My current process:
1) Track the green screen in Mocha
2) Export the shape data from Mocha to a mask of the source footage in AE
3) Export the corner pin data from Mocha and apply it to the replacement footageIs that the best way to handle this? Or is there some more efficient way to handle it?
Possibly worth noting, those white cards that are covering up parts of the green screen footage will actually be place on top of the green screen during the shot.
The real footage will be really well lit and shot at 4K, so I’ll have solid footage for keying and tracking.
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13 Replies
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Will the camera move or will it be a locked shot?
Base on that and on how complex the move is you may want to use a 3d tracker.
One other thing to consider is animating the cards that come on top in post.Tudor “Ted” Jelescu
Senior VFX Artist -
Camera will be moving all over the place (up, down, left, right, tilt, pan, etc). It’ll be a huge scene with dozens of these little green cards I’ll need to track and key.
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I would choose a 3d tracker then for this.
I am still wondering why not build everything in AE… what would be the advantage of shooting? You can have a lot more control in post over the camera moves, timing of elements and so on.Tudor “Ted” Jelescu
Senior VFX Artist -
The entire shot (over 3 minutes long) will make use of literally hundreds of photos. Some will be plain photographs, others in frames…all set down by various hands. It’s not possible to setup the entire shot in AE (or even a 3D program like Cinema 4D).
So, I definitely need to figure out how to properly track/mask/key this stuff.
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Since everything is on a 2D plane, I’d definitely use Mocha for the tracking. You won’t need the shape data; only the corner pin data, as your green screen will cut the shape for you.
Be careful not to put your tracking markers in the shadows of the overlying pictures or you’ll have to paint the shadows back in. Mocha will not need that may tracking markers either; the five markers in the center are more than enough.
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I don’t see how I can get around NOT needing the shape data. Adjusting the key color will almost certainly affect the rest of the shot, so I’ll have to mask all non-chroma footage for each green screen layer so that it doesn’t screw up the color for everything.
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Could it be possible to shoot the hands laying down photos on chroma and build the whole ensemble in post? It may take a bit of planning but I still think you have more options and control.
Tudor “Ted” Jelescu
Senior VFX Artist -
Not possible. Shoot is tomorrow morning. Don’t have time to change all that.
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Just as a safety, shoot a locked down shot of all hands coming in and out of the frame and laying down the cards. This way you’ll have at least a safety if the rest does not work as planned.
Mocha is a great tracker and it may work if you can split the piece in pieces, but for one long moving shot I maintain my initial opinion- a 3d tracker will be best.Tudor “Ted” Jelescu
Senior VFX Artist -
I assume you’re planning on pulling a key from the green card; this will create your mask. So I’m not sure what you mean by “adjusting the key color”. You can simply garbage mask anything else in the scene that happens to be close to your green key color. You can also mask out the tracking markers after you’ve pulled the data from them.
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