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-   -   Stereo Vision Greenscreening (https://www.dvinfo.net/forum/3d-stereoscopic-production-delivery/126897-stereo-vision-greenscreening.html)

Anmol Mishra July 29th, 2008 04:57 AM

Stereo Vision Greenscreening
 
Well. I have figured out some issues with using a dual camera setup without LANC. I will use a Sync Comparator to check drift and will re-shoot if the sync is a problem. Frame-by-frame sync will be done using a clapper board..

There is another problem. 3D green screen has a different meaning in NLE's. It simply indicate a non-flat object. However, I have not found any solution for stereo-vision green screen solutions.

Does anyone have a suggestion ?

Dylan Pank July 29th, 2008 05:42 AM

Anmol, it's not that confusing. there is no "3d greenscreen" as a 3D image imported would be generated with an alpha channel, so all greenscreen would be shot as flat video. These flat images in a virtual 3D space are commonly referred to as 2.5D to distiguish them from 3D virtual objects. Anyway, is there a NLE on the market that actually handles 2.5D space properly? I would have thought that the domain of effects and compositing programmes (After Effects, Motion, etc). If they do I think that it would be limited to a simple Z channel control and X or Y rotation, no ability to move a virtual camera around an anchor point off of the Z axis for example.

You would need to shoot the background plates with the exact same camera(s) set up (focal lengths, DOF, interocular distance and Conversion) then green screen separately to each left eye/right eye camera.

That or you could create the Background plates in 3D CG, rendering twice from slightly different in order to simulate the binocular effect, closely recreating the same convergence, focal length, and interocular of your real shoot.

Anmol Mishra July 29th, 2008 08:24 AM

Quote:

Originally Posted by Dylan Pank (Post 913622)
Anmol, it's not that confusing. there is no "3d greenscreen" as a 3D image imported would be generated with an alpha channel, so all greenscreen would be shot as flat video. These flat images in a virtual 3D space are commonly referred to as 2.5D to distiguish them from 3D virtual objects. Anyway, is there a NLE on the market that actually handles 2.5D space properly? I would have thought that the domain of effects and compositing programmes (After Effects, Motion, etc). If they do I think that it would be limited to a simple Z channel control and X or Y rotation, no ability to move a virtual camera around an anchor point off of the Z axis for example.

I think Avid is offering 3-D editing and Premiere Pro has a plugin. But these offer a simple side by side editing stream of the left and right streams.

Quote:

Originally Posted by Dylan Pank (Post 913622)
You would need to shoot the background plates with the exact same camera(s) set up (focal lengths, DOF, interocular distance and Conversion) then green screen separately to each left eye/right eye camera.

This limits the background to something actually available, maybe a 3-d picture. Maybe a 3-d picture that I can take.

Quote:

Originally Posted by Dylan Pank (Post 913622)
That or you could create the Background plates in 3D CG, rendering twice from slightly different in order to simulate the binocular effect, closely recreating the same convergence, focal length, and interocular of your real shoot.

Yes :-( This seems a bit complicated with a steep learning curve. We are talking Maya or 3dstudio here..

Zack Birlew July 30th, 2008 11:31 AM

Either way, you're going to be editing and doing effects for everything twice. So, you have to have that mindset for everything. As far as viewing things in 3D, there is a 3D player out there that you can download. I can't remember the name of it unfortunately, you'll just have to search around. The only other thing I can think of is Nuke, which has a bunch of new whizbang 3D features now.

Ron Labbe July 31st, 2008 07:14 AM

Actually you don't need special software to view in 3D... for instance, in MAX I have L and R camera viewports next to each other, so I can freeview or use some kind of viewing aid to view in 3D, in real time.


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