Dual projector solution?

[vger]

Ok, so I have been considering the dual projector approach for home theater. Using passive glasses has it's pro's and cons, but I already have a pair of projectors and polarizing material etc.

I came across a unit made by VNS that may fit the bill for splitting the feed into separate L and R signals. I found a page referring to the "VNS G-500 Mulit-Video Image Processor" at this site...

http://www.kkuse.com/news/2.html" onclick="window.open(this.href);return false;

Has anyone got any idea where to locate one of these? Or what the $$ damage will be?

Thanks

[cybereality]

Hmm, never heard of it. Could be interesting if its real.

[Likay]

Dunno either.
You're planning to watch 3d-broadcasts right? Otherwise i don't really know how useful this device would be compared to a computer. All 3d-players except nvidias stereoplayer (rip of stereoscopic player anyway) supports dual projection. Tridef and iz3d supports 3d-gaming with dual projection while nvidias 3d-vision does not. If the quality is decent the unit would probably fix the one-frame-lag that can be apparent in such rigs.

[motorman45]

Is anyone here using dual projectors and optoma 3dxl's ?

[BlackShark]

I don't think so, most people here are already PC gamers, ther is very little point in buying converters if you already have a powerful gaming PC. (all high end GPUs have dual outs)

If the quality is decent the unit would probably fix the one-frame-lag that can be apparent in such rigs.

I got rid of the 1-frame lag using side by side output and ATI Eyefinity to lock both outputs in sync.
It's supported by Stereoscopic player, most side by side content wotrks natively as long as your video player offers proper scaling options and for games it's supported by both DDD-Tridef and iZ3D drivers.

[motorman45]

Here is a dual projector passive 3D setup ive used for Call of Duty and UT3, running off of a Nvidia Quadro fX 5700 and Tridef

http://www.youtube.com/watch?v=RiWf_69xHW0

it is not polarization, no silver screen...

[bgnome]

Here is a dual projector passive 3D setup ive used for Call of Duty and UT3, running off of a Nvidia Quadro fX 5700 and Tridef

http://www.youtube.com/watch?v=10xwnUi5 ... ure=relmfu

it is not polarization, no silver screen...

looks to be a dolby setup. i have heard some good things about it, although you may need to tinker with the color a lot and glasses are not as readily available..

[motorman45]

looks to be a dolby setup. i have heard some good things about it, although you may need to tinker with the color a lot and glasses are not as readily available..

It is not Dolby. it is the same as Panavision 3d if youve seen that. the color is very close to native 2D settings. you can buy the glasses easy for this setup on ebay, its listed under omega 3d kit.

[Doon1]

With 80" passive TV's that are plug-and-play why go through all the trouble of doing a dual projector set-up?
John

[PalmerTech]

With 80" passive TV's that are plug-and-play why go through all the trouble of doing a dual projector set-up?
John

Where can I get one of these 80" passive 3DTVs?

[cybereality]

Well you could also get an HD 3D DLP projector for around $600. Much easier than a dual PJ rig.

Haven't heard of any 80" passives available today, but the LG 84LM9600 should be coming out this summer. Probably costs a fortune though.

[BlackShark]

Well you could also get an HD 3D DLP projector for around $600. Much easier than a dual PJ rig.

Cheap DLP projectors don't offer the same features as dual-projector systems. Yes indeed they're cheap and easy but the results you get are in par with what they're worth.
Dual projectors systems have specific advantages you can't get any other way.

I am currently trying Motorman's interference filters solution, It is a very interesting solution but I ran into colour correction issues with the first batch of filters, I'm waiting for modified filters to arrive to write a full in depth report.

[motorman45]

there were some color issues with the original filters when used on an LCD projector. hopefully that is corrected as much as possible with the new ones we are sending out now.
on the projectors though im running two $300 DLP units ( reman off ebay ) that can run 720p 60 hz in the dual stack. got the Nvidia quadro fx 5700 for $99 also off ebay and the dual core work station i had laying around. without the cost of the filter set it really cost me less than $750 to put it together and i have a really bright 3D image on 140" white screen. how can you beat that with a flat pannel.
i like the DLP projectors for not only their lumens but full spectral output and the fast response for gaming.

[BlackShark]

got the Nvidia quadro fx 5700 for $99 also off ebay

It's a nice solution for playing movies, but this is MTBS3D, the main topic here is games.
Until we can get a proper hdmi or DisplayPort splitter that can do full resolution at good framerates for cheap, playing games on dual-projectors still restricts choices of hardware and software, you're pretty much stuck with AMD graphics cards and DDD is the only solution to play games.

[Neil]

Hi Blackshark,

I know the Quadro's aren't the best gaming GPUs, but why would you be forced to use an AMD GPU in this case? This is a few years ago already, but we had to use a Quadro GPU for our Unreal Tournament 3 in 3D demo at SIGGRAPH with the iZ3D drivers, and that was a dual output. Even the iZ3D monitors worked based on dual output on an Nvidia GPU - so DDD should work in the same scenario as well on both AMD and Nvidia GPUs.

Unless I'm misunderstanding the conversation - I admit to being late to the party!

Regards,
Neil

[WiredEarp]

on the projectors though im running two $300 DLP units ( reman off ebay ) that can run 720p

2 720P projectors doesn't even give you a decent resolution however.
If you are going for multiple projectors to improve brightness etc, surely higher resolution would also be a useful point.

Just an idea as well, but if you have 2 DLP 3D projectors, can you double them up on the imagery and gain 2x brightness that way? If you had the correct HDMI splitters etc would they switch in phase with each other? if so, that would probably be the best solution for both brightness AND useability, since you could split them into a 2 projector 3D setup, or align them for a high brightness 720P 3D setup.

[BlackShark]

Hi Blackshark,

I know the Quadro's aren't the best gaming GPUs, but why would you be forced to use an AMD GPU in this case? This is a few years ago already, but we had to use a Quadro GPU for our Unreal Tournament 3 in 3D demo at SIGGRAPH with the iZ3D drivers, and that was a dual output. Even the iZ3D monitors worked based on dual output on an Nvidia GPU - so DDD should work in the same scenario as well on both AMD and Nvidia GPUs.

Unless I'm misunderstanding the conversation - I admit to being late to the party!

Regards,
Neil

The problem is that consumer cards don't offer the frame-lock feature that professional cards have. Because of this lack of frame-lock, multiple outputs don't refresh at the same time which leads to the 1-frame-lag issue that affects all multi-output solutions on consumer cards.
When both eyes aren't refreshed at the same time, it creates eye strain as well as a motion distortion artefact which modifies the horizontal parallax when there is horizontal motion (changes depth, can lead to depth violation) and creates vertical parallax when there is vertical motion (eyestrain).

This also happens with frame sequential displays, but the amount of the effect is not the same.
Frame sequential displays typically work at 120Hz, so the lag between the eyes is 1/120 of a second, all the time.

With non-synchronized dual-outputs displays, the lag is variable, let's assume we're using 60Hz displays (iZ3D monitor or projectors)
First there is the base lag due to the lack of display sync : it's a random amount of lag which can vary between 0 second and 1 refresh period = 1/60 of a second

Then there is the frame rate issue, in games the 1-frame-lag kicks in, the primary display get's it's picture as soon as possible or at the first refresh available if v-sync is enabled, but the secondary display only gets it's picture on the next frame. I don't know why (probably something to do with the way Windows and DirectX work), but it's just happens like that on every graphics card I've tested. (Geforce 8800GTX, Radeon HD5870, HD6850, HD7970)
The lag created varies according to the frame rate.
-if the game has a significantly higher frame rate than the refresh rate (more than 60fps), there is a chance that the next frame will be completed before the refresh sync and both pictures will be displayed at the same time (in addition to the unsync base lag)
-if the game runs at 60fps, the 1 frame lag will make the picture for the secondary display too late to catch the refresh sync and the picture will be displayed with 1/60 of a second lag (in addition to the unsync base lag)
-if the game runs at 30fps, the 1 frame lag will make the picture for the secondary display too late by twice the refresh sync and the picture will be displayed with 1/30 of a second lag (again in addition to the unsync base lag)
-etc... 20fps -> 3 times the sync -> 1/20 s lag, etc...

For static scenes there's no problem, but when things are in motion, these lags become significant problems.
The iZ3D monitor has an advantage, because of the special colour + polarisation pixel format, the 1-frame-lag would not cause eye disparity, but dual projectors get hit head on with it one eye sees a completely different picture than the other eye : when I get that much lag, I just can't watch the picture : it hurts my eyes too much.

The only way to counter this is to make the graphics card manage both outputs as one single display at a low level (not just emulating an extended/spanned desktop)
AMD Eyefinity allows this under very tight restrictions (exact identical outputs : resolution, framerate and cable/adapters) and that's the way I do dual-projectors
Nvidia Surround does NOT allow it at all (Nvidia surround (2D or 3D) requires 3 displays)
An other way to do it would be to use a Matrox Dualhead2go, but it's only theory, I haven't read any reports of people testing this solution. I do not know exactly how the Matrox drivers interact with Windows or games, so I do not know if this solution works until someone can test it.

I think salvation for dual-projectors would have to come in the form of an active converter capable of transforming HD3D or 3DTV Play inputs (Hdmi 1.4 3GHz or DisplayPort 1.2) and convert them to Left/Right dual head outputs (dual DVI or dual hdmi).
Such conversion is currently possible for hdmi1.4a (minimum spec) but is expensive : it requires 3 devices (1 hdmi1.4a splitter and 2 Optoma 3DXL).
There is currently no such solution supporting stereo 1080p60.

[Doon1]

With 80" passive TV's that are plug-and-play why go through all the trouble of doing a dual projector set-up?
John

Where can I get one of these 80" passive 3DTVs?

My bad. i was reading about the new LG 80" class 3D TVs and thought they were out already. the 65lm6200 is a 65" that can be had for about $2000.

Have you checked the forum over at stereo3d.com some of those guys have some serious projection setups.
John

[motorman45]

I have been playing UT3 , Portal 2 and CoD on my demo rig. i know its PC based and we were first aiming at movies in passive 3D with the system but im a long time gamer and this thing rocks on UT3.
the quadro is not my first choice in cards to make a dual projector passive 3d rig but its what i had on hand. my home gaming system is way better and im planning on building a new PC and setup some spare DLP rigs in my home office with a curved 96" screen. i finnaly found some decent screen warping software to work with windows. ive got 2 1080P DLP projectors and i will have to see how smooth it is.

[Soulnight]

Hi there,

is it possible to play in 1080p 3D 60Hz with nvidia 3D vision on a passiv 3D dual projector solution WITH a Nvidia professional QUADRO card?

In the help of nvidia, I understand it is possible but I am not sure until someone has tried it out:
http://nvidia.custhelp.com/app/answers/ ... -windows-7

Could you please try it Motormann?

You don't need an 3d vision emitter to activate 3D vision since there is an emulator for this:
http://3dvision-blog.com/forum/viewtopic.php?f=9&t=997

It would be GREAT news if we could activate 3D vision for GAMES with a quadro card on a dual projector setup with passive 3D 1080p 60Hz... BECAUSE there is now a HACK for modding a GTX 680 (350€) into a Quadro K5000 (1500€):
http://www.eevblog.com/forum/projects/h ... #msg207550

Cheers,
Soulnight