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Product behind a green screen with moving camera shots

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Steven Probets
Product behind a green screen with moving camera shots
on Dec 17, 2013 at 1:59:21 pm

Hi everyone!

Basically this is something I have never done before so I wanted the best advice on how to get what I want to achieve.

Basically a product and the camera rotates around it and we highlight some features. The product is behind a green screen. I need to key video into the green screen with the product in the centre.

Think of a ball, the product is in the centre of the ball, the camera moves around the product on the lining of the ball focusing on the centre product. The ball is a basically a spherical video wall - with various videos side by side.

How can I achieve this effect in After Effects? So I will get the green screen video with the camera rotating around it. Now I need to implement a spherical video wall around it which complements the camera movements.

I have After Effects CC so maybe Cinema 4D would be helpful? I have zero experience in Cinema 4D though but willing to take on a challenge!

Hope that makes sense.

Thanks


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Chris Evans
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 3:24:28 pm

I would love to help you, but I just don't quite understand everything you are trying to do. I get the product and the camera movement, but what kind of video green screen are you talking about? Do you have a piece of footage that you want to be a sphere? Do you have various piece of footage that you want to make a circle?

If you could include a picture, that might help.

Maybe someone else will understand better than me.


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chris brett
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 3:30:43 pm

--- highly recommend 3D model for the pack shot if at all possible --- in my experience much better and easier --- probably more cost effective as well if you know a good 3D guy.........

With regard to the background tend to do stuff like this by trial and error - build video wall / bend video wall / move camera etc etc but there will be a much better and technically accurate way of achieving this which I expect others will advise you on............

----------------------all the best--------chris--

================================================


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Dave LaRonde
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 4:16:08 pm
Last Edited By Dave LaRonde on Dec 17, 2013 at 4:19:13 pm

Put the product on a turntable in front of the green screen. No muss, no fuss, just watch out for glare on shiny spots. A little futzing at shooting time can save you a lot of needless time in post.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Steven Probets
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 4:54:56 pm

Thanks guys, givine me food for thought!

I guess a simple, statement would be how would I go about getting a video that I keyed into a green screen background moving in tandem with the real object which was filmed with a camera orbiting it?


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Dave LaRonde
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 5:06:20 pm
Last Edited By Dave LaRonde on Dec 17, 2013 at 5:09:42 pm

Ugh. That doesn't sound like fun.

If this background video is supposed to be spherical shaped, so you can move the real-life camera around at will, how big is the imaginary sphere and how big is the background video?

I'd imagine most backgrounds like this are built in a 3D application.... as is the subject, which you're currently shooting on a green screen, presumably without the benefit of a motion capture rig.

It gets a lot easier if it's all in a real 3D app.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Steven Probets
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 5:12:39 pm

It doesn't have to be spherical and I'm thinking it shouldn't be. Maybe a wall of video and when the object moves (or rotates) then the video wall would move to a focus onto another video (there will be 6 videos in a grid on one wall). Each video is shown at the same time as one feature is shown, then another feature - another video and so on.

The trick here, I guess, is to get the movement of the wall in relation to the camera to compliment the exact way the object moves (while it was being filmed).

So, how can we get a background move in the same way as the camera was when filming the object?

I'm thinking maybe I need to use the 3D camera tracker?


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Chris Evans
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 5:20:06 pm

3D camera tracker seems like exactly what you should use. The one that is build into After Effects does a pretty decent job. Shooting your product on a Green Screen turntable like Dave suggested. If you could also cover the turntable with some green cloth, put some track points on it and shoot wide enough so you can see the turntable, your 3d tracker would love you, just key out the BG, but not the turntable when you track it or you'll confuse your tracker with stationary points.


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Dave LaRonde
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 5:29:17 pm
Last Edited By Dave LaRonde on Dec 17, 2013 at 5:36:12 pm

I recommend a visit to a web site called Hollywood VFX or Hollywood FX; I forget which. They have some setups there for tracking chroma key shots, along with sample footage you can download. Very helpful in figuring out a shot like yours.

I once had an art director who insisted a camera could do a 120-degree arc around a subject against a green screen. I pointed out that at some point, the subject would almost certainly no longer be in front of the green screen. He didn't believe me, I was instructed to have it shot to his demands, he tried to get the shot to work..... and it was scrapped.

The point of this anecdote is to think in terms of planes in 3D space and previsualize what you want to accomplish. After this exercise, just for the sake of practicality, you may want to come up with a Plan B.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Steven Probets
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 5:37:18 pm

Thanks Chris, yes I think I am having this video pictured in my head finally. When the features are highlighted text will appear and I was thinking of using the text move with the product (a common effect nowadays).


Thanks Dave. Literally in the last 30 minutes this is why I'm scrapping the 3D spherical wall thing. Thanks to help on here and picturing the planes and visualising it in my head I don't it is going to work.


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chris brett
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 7:02:16 pm

Hi Steven

--------dont forget you can build a high res video wall / use as a layer / add a curve / use a 'wide angle lens' on your AE camera / whatever ........ motion blurr .......

........... and if you are using animated text as well you should be able to 'get away' with quite a lot -- ie if its not technically correct it can still look convincing and pretty good in the edit .


------------------------------ chris


======================================================


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Walter Soyka
Re: Product behind a green screen with moving camera shots
on Dec 17, 2013 at 8:49:16 pm

I'll suggest a different route than everyone else -- consider doing the turntable moves in post.

Shoot one revolution on a motorized turntable with a slow and steady motor, then use time-remapping to alter the timing/speed. You can link this to camera rotation with a little simple math, eliminating the need to try to match motion. Alternately, shoot a pile of stills at regular rotation intervals.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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