Stereo Vision Greenscreening at DVinfo.net

Anmol Mishra · July 29th, 2008, 04:57 AM

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

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

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

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.

July 29th, 2008, 04:57 AM	#1
Anmol Mishra Major Player Join Date: Jun 2007 Location: Sydney Australia Posts: 401	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 ?

July 29th, 2008, 05:42 AM	#2
Dylan Pank Major Player Join Date: Nov 2004 Location: Portsmouth, UK Posts: 611	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.

July 30th, 2008, 11:31 AM	#4
Zack Birlew Major Player Join Date: Sep 2003 Location: Las Vegas, NV Posts: 613	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.

July 31st, 2008, 07:14 AM	#5
Ron Labbe Regular Crew Join Date: Jul 2008 Location: Maynard MA Posts: 40	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.