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Manvendra Singh Chauhan (Maanavendra)
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Username: Maanavendra

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Posted on Saturday, June 12, 2010 - 2:08 pm:   Edit PostDelete PostView Post/Check IPPrint Post

I have a problem regarding Active Stereo 3D Projection. The 3D Software outputs in 3D frame sequential(60 Hz each for left and right eye, alternatively) format. Graphics Card, Nvidia QuadroFX 5800, has 2 DVI outputs and stereo projector is Active Stereo Projection Design F10AS3D, that takes 2 identical DVI graphics outputs as inputs and projects active stereo 3d image by synching/switching with emitter and Active Stereo Eye wears. What splitter/format converter should be used to convert single frame sequential Gralhics 3D stream to 2 identical Graphics, over 2 DVI-I outputs for Active Stereo 3D projection in such setup?
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Fronzel Neekburm (Fronzel)
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Posted on Saturday, June 12, 2010 - 2:47 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Well at first - if your DVI outputs are "identical" they are not stereoscopic, if you want to output stereoscopic over 2 DVI you need to send left picture on one right picture on the other. Otherwise it simply doesn't make sense, if you cant output that you cant use 2 DVI outputs. The projector is the one who makes a frame sequential format out of its 2 DVI inputs, it has a DLP-Link port to synchronize with your DLP-Link compatible shutter glasses. There are probably many other possibilities, but if you buy such a specialized projector i would recommend to use it as intended to get the best picture quality.
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Manvendra Singh Chauhan (Maanavendra)
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Posted on Sunday, June 13, 2010 - 4:16 am:   Edit PostDelete PostView Post/Check IPPrint Post

Hi Fronzel, Yes. The projector does all the switching/syncing to create and project Active stereo 3D content out of 2 identical DVI graphics strreams. Only problem is that software itself out-puts in frame sequential format while projector needs 2 DVI inputs. It does not recognize/accept Frame Sequential input. If the output from Computer/Card was simply a DVI stream, it would have been simple as either we could have cloned the out put on 2 DVI outputs of graphics card or used a 1X2 DVI splitter and fed those 2 DVI outputs to projector.
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Fronzel Neekburm (Fronzel)
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Posted on Sunday, June 13, 2010 - 11:47 am:   Edit PostDelete PostView Post/Check IPPrint Post

Hmmm, i have only used seperate left/right pictures, as this is what the projectors inputs are labeled and that works fine as intended. I am still a bit confused you have such a specialized projector but no way to generate the proper output, i think you would have more fun with a passive 3D projector.

I have looked on the projectiondesign homepage and they generally say "no". How you can use a "clone" setup as 3D is beyond my understanding as with 2 dvi streams you either have left/right which is stereoscopic or you have one 2D picture cloned - which is NOT stereoscopic. How that should work i can not imagine.

They also write there is some converter by cyviz, but i never heard about it before.


http://www.projectiondesign.com/?CatID=1715&ItemID=3924
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Tony Asch (Tone)
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Posted on Sunday, June 13, 2010 - 12:38 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Perhaps there is something lost in translation here?

The F10AS3D has 2 DVI inputs which are identical in their electrical specifications. However, the actual data they must receive in order to show stereo 3D must be different. One DVI input receives the left eye image stream and the other receives the right eye image stream.

While I suspect the easiest solution to the OP's original problem may be in software, there's not much more to suggest until the OP tells us what software is being used to generate the 3D.

Interestingly, it appears that with the addition of an active polarizing shutter plate in front of the projection lens, the F10AS3D could do passive 3D projection.
VRtifacts.com
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Manvendra Singh Chauhan (Maanavendra)
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Posted on Sunday, June 13, 2010 - 3:08 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Please see document at http://www.mediafire.com/file/vwmzdzt2zom/Startup AS3D.pdf , that they call startup, that in fact is setting up projector for 3d . Passive stereo is not an option , unfortunately. DepthQ also offers a modulator for that purpose(passive). We need a format converter + splitter that recognizes frame sequential forma, decodes it and simply splits the signal into 2 identical graphics over DVI.
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Manvendra Singh Chauhan (Maanavendra)
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Posted on Sunday, June 13, 2010 - 3:12 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Please see document at http://www.mediafire.com/file/vwmzdzt2zom/Startup AS3D.pdf , that explains setting up the projector for Active 3d Stereo with Nvidia Card. Passive stereo is not an option that otherwise is also possible with Depthq polarization modulator http://www.depthq.com/modulator.html .
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Manvendra Singh Chauhan (Maanavendra)
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Posted on Sunday, June 13, 2010 - 3:28 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Question is, will it matter if the output from software is in frame sequential format or not, as long as Nvidia Card is cloning the output on it's 2 DVI outputs OR a 1 input-2 output DVI splitter is being used on 1 dvi port of the card , and resulting 2 identical DVI signals are input to the projector? All the processing for Active Stereo 3d rendering is being done by projector itself.
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Tony Asch (Tone)
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Posted on Sunday, June 13, 2010 - 4:03 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Perhaps this is a misunderstanding of the Nvidia driver software. Nvidia utilizes the "clone" mode format of its dual output cards when enabling the stereoscopic driver features. However, in stereo+clone mode, the actual images being output from the two DVI ports are different: one is a left eye view and the other is a right eye view. The images are not identical, hence a 1-2 splitter would not work either.

However, if you are using Stereoscopic Player software, you can skip the Nvidia 3D setup and just use Horizontal Span mode. That's why I asked about what software you are using.

Having built and used lots of shutter plates for projector lenses, I feel quite certain that a linear polarized plate could easily be built for this projector. A shutter plate with passive glasses has essentially the same principles of operation as active glasses.

LCD shutters have the ability, under electronic control, to either twist polarized light by 90 deg. or to leave it alone. Active shutter glasses are built so that the light first passes through a sheet of polarizing material, then passes through the LCD shutter, and then passes through a second sheet of polarizing material. If the two polarizers are aligned, the light will pass all the way through when the LCD does not twist the polarization, but will be opaque when the LCD shutter twists the polarization by 90 deg. Active glasses have their LCD shutters synchronized with the video frames/fields to allow the proper image to pass to each eye.

Shutter plates do exactly the same thing. The plate is composed of a polarizing sheet and an LCD shutter. The projector light passes through the polarizer and then the LCD shutter which alternately twists or passes the polarized light. The light then bounces off a silver (polarization preserving) screen, and finally passes through a second polarizing filter in the passive glasses. Since passive glasses have the two polarizers aligned with a 90 deg. difference, one eye will only see the twisted light, while the other eye will only see the un-twisted light.

If you are willing to peel off the 2nd polarizer on one lens of some active stereo glasses, you can demonstrate this yourself. Use the modified lens as the projector shutter plate (polarizer towards the projector) and wear passive linear polarized glasses. This will work on any DLP projector which supports active glasses. And yes, you do need a silver screen.

Hope this helps.
VRtifacts.com
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Manvendra Singh Chauhan (Maanavendra)
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Posted on Sunday, June 13, 2010 - 4:28 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Thanks Tony. It has made many things clear. Confusion regarding Nvidia Driver was one of them. if Nvidia card's 2 outputs are separte for each eye, then only issue left is the inputs to the projector. It has not been explained in the projector set up, but it looks like it's 2 DVI inputs accept separate left and right eye signals. What do you think? I have tried to clarify from the manufacturer, but their Indian presence is minimal, (no specialist here), and have not been helpful in clarifying the issue.
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Tony Asch (Tone)
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Posted on Sunday, June 13, 2010 - 4:35 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Yes, the two inputs on the projector correspond to left and right inputs. You should be able to connect the 2 DVI outputs of your computer directly to the 2 DVI inputs on the projector.

Without any special drivers, you can set Nvidia to "Horizontal Span" and use Stereoscopic Player to test this configuration. Stereoscopic Player natively supports dual output stereo. A trial version is free and they have some stereoscopic movies on their website for download.

I sympathize with your situation. Even though I'm US based, I've done a lot of 3D video work in India and the lack of local support drives me crazy! That being said, the market potential is immense.
VRtifacts.com
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Manvendra Singh Chauhan (Maanavendra)
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Posted on Sunday, June 13, 2010 - 4:59 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Many thanks Tony and Fronzel for your quick and effective response. Yes. Market for 3d VR is small at this point here but holds a lot of potential. We work in 3D VR/AR Technologies and technical support is all remote. It is possible that due to small size of the market, companies do not focus on support. If you work/have worked in India then may be, we can work together on some projects, in future.
Thanks again.

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