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Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
http://www.mtbs3d.com/phpBB/viewtopic.php?f=26&t=2569		 Page 1 of 2
Author:  ignatius [ Wed Jan 07, 2009 11:16 pm ]
Post subject:  Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
Hey all,

I was wondering if there are any experienced members in this forum who have built their own home theatre setup for 3D stereoscopic content using the passive polarization method. There were a few things I could use some help with. Before posting this message I had researched all over the internet, in this forum, googling, the works but I could not find the answers or I should say the right 'materials' I need to build this home theatre. I have come across this thread, http://mtbs3d.com/phpBB/viewtopic.php?t=509 and found it very informative and helpful. But it's slightly different than the setup I'm building. Mainly because I have to build the silver screen. This is going to be a long post so I hope people don't mind reading a lot.

I'm building my first home theatre 3D stereoscopic projection room. I will be getting a couple of Optoma HD7100 projectors. There is a review of it here, http://www.projectorreviews.com/optoma/hd7100/. I will use them with 2 linear polarized filters in front of the projector lens that will be projected onto a 140" (diagonal) silver screen with a pair of linear polarized glasses that you wear to watch the 3D content. This theatre room will be in a light controlled dark room. I've researched about the differences between the linear and circular polarizer's but the differences are very small in terms of 3D quality and the price in comparison is huge. So I will be sticking with the linear polarization method for now and maybe upgrade to circular in the future.

Before going on I would like to mention that this whole setup is for the average joe, a poor-man's theatre room, and a do-it-yourself as much as you can to save some bucks project. So the goal is really to find the best and cheapest material to get almost similar (or hopefully identical/superior) results from professional products.

One of the issues I have are finding the best polarizer materials for the filter and 3D glasses that is made of great quality and is relatively cheap. The goal is to achieve as little ghosting as possible. There were a number of online stores I found that sell cheap polarizer material. Here are a few:

http://polarization.com/
http://www.3dstereo.com/viewmaster/pj-pfilt-3x3.html
http://www.3dlens.com/shop/polarizer.php
http://www.berezin.com/3d/3dglasses.htm#Polarized
http://www.studio3d.com/pages/store.html

Does anyone have any experience with any of these online stores and can comment on the quality of their polarizer products? Another solution I found on the net was to buy polarizer filters that are used with photo cameras. I found this solution here, http://www.scec.org/geowall/filters.html. In trying to achieve the best possible quality and the least amount of ghosting (cross-talk) when viewing 3D content. Which polarizer would be the best? The filters that are used for photo cameras? Or from one of the links above? I read that if you use different polarizer's for the filters then the ones used on the 3D glasses, that this will add to the ghosting effect. So if this is true, this would mean that using the filters used for camera lens wouldn't be the best idea, because the polarizer on the 3D glasses would be different. Someone can correct me if I'm wrong.

The other issue is building your own silver screen for 3D. I don't have the budget to spend $300-1000 on a readymade silver screen from professional companies. The best solution and possibly the cheapest depending on the size of your screen if you were to buy a professional made product was the 'Ultra Silver 3D' paint from Goosystems (http://www.goosystems.com). This product looks great and seems to work really well. But it's still a few hundred too expensive for me. Just for the sake of this thread I will post up some places where you can buy readymade professional silver screens for anyone who does have the money to spend on it.

http://www.paintonscreen.com/index.html
http://www.silverfabric3d.de/html/sf_silver3d.htm
http://www.lighthouseprojection.com/index.html
http://www.berezin.com/3d/screens.htm
http://t-works.en.ecplaza.net/product.asp
http://www.stewartfilm.com/
http://www.harkness-screens.us/ss_3d_spectral240.htm
http://www.dalite.com/

I came across two extremely helpful and inspiring links on the internet about building your own 3D projector and silver screen from scratch.

http://www.lumenlab.com/forums/index.ph ... ode=linear
http://www.allinbox.com/vp3d/vp3d.htm (in French, use babelfish to translate)

They did a great job explaining everything in detail. One of them painted their wall to use as a silver screen and the other used a special silver fabric. The best type of paint to use for a silver screen is apparently a white metallic paint, or essentially any kind of metal paint which have polarization properties. Another tip I found was to use a matte paint over the silver screen to get rid of most or all of the unwanted bright hotspots. But would this effect the polarization of the screen? You can even use silver aerosol paint spray cans to make the silver screen with decent results. Another person on the internet (forgot where) mentioned he used silver nylon used to cover vehicles that seemed to have worked very well. I have not been able to confirm any of this myself yet, just simply reading what other people have done with some results.

I have yet to experiment all the different types of silver paints/fabrics to find the best one to use as a silver screen for 3D. I was hoping there would be someone on the forum who could point us to a specific kind of paint or fabric that they have used that seems to work really well with minimal to zero ghosting. That they can find in your local hardware/paint/fabric store.

I would really appreciate any kind of help that anyone can offer on this topic/project. I will continue to post my own progress with building my home theatre 3D setup and will post any useful information I may come across or find.

Cheers,
Varinder
Author:  Tril [ Thu Jan 08, 2009 12:31 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
I don't think it will be bright enough at 1000 lumens with a diagonal size of 140". I've got an Optoma HD71 that's rated at 2400 lumens, a silver screen, a distance that gives me a screen size of about 100" and a polarizing filter. With the filter on, it's just the perfect brightness. I also have an Optoma EP739 that's rated 1700 lumens in eco mode. On the same screen at the same distance with the same filter, that second projector is not bright enough. Everything turns very dark. Details that are clearly visible with the HD71 become invisible with the EP739 because everything that's close to grey/black is seen as black.

If you want to go cheap on the filters, you can buy some sheet polarizer for about 30$ at Edmund Optics and cut it to the size and shape of your choice.
If you want to go more expensive, you could order a pair of polarizing filters laminated between glass with anti-reflective coating that are 4"x4" (or bigger) from API American Polarizers for around 150$. I'm suggesting them because I ordered a pair of filters from them. They are of good quality.

About photo cameras, you risk burning them (I haven't tried them so I can't confirm if this is likely to happen). If the filters get too hot, they break. I've had that happen when I tried to use some very cheap polarizing glasses theme park style as a temporary filter while testing the projector.

A word of warning about making you own screen. You can succeed or you can fail. If you fail, that's wasted money. If you use aerosol cans, you will most probably not be able to do a clean job. If you use a roller, it will be very hard to make a screen without texture. Your best bet is to use a spray gun but you'll need to buy one and that adds to the cost. I tried to make my own screen and in the end, I failed. I tried to use cans and it turned out ugly (visible circles, streaks). I then tried to use a roller but it left a visible texture and I messed up the choice of paint so it did not preserve polarization enough. It's not impossible to make a screen but if you're an average painter, you might fail on your first try. You might also have difficulty finding the perfect paint. You need a metallic paint but you need to find one that does not sparkle too much. Since it's to put indoor, you need a paint that won't smell for a long time.

I also made my own screen out of wood. The design is bad and the wood is showing through the fabric. I could post some pictures, to give ideas about what not to do.

I tried a few different paints and painted small canvas (about 12"x10") to test on samples of the paints. I could try to find those samples tell you which ones seem likely to work, which sparkle too much and which don't work at all. I think I still have that somewhere.

I could also take pictures of my homemade projector holder and post them.

You could buy cheapers projectors and buy a screen.
Author:  ignatius [ Thu Jan 08, 2009 1:55 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
Hey Tril,

Thanks for the feedback. I would love to see the pictures you took of your experiments if you don't mind sharing them. It's too bad you were unsuccessful in building your own silver screen. I had a good feeling that using aerosol cans wouldn't work well. Somebody had mentioned that somewhere else and said he got decent results with it. But i don't think i would be satisfied with the results myself. But i will still give it a try. You are right that it is best to spray paint a silver screen instead of rolling. Rolling would shoot the polarized light off into the wrong direction, whereby spraying the silver screen the polarized light is projected back to the viewer properly. There was a site that explained this perfectly specifically for painting silver screens for 3D, I will try and find it.

I have read that if you use a metallic paint and finish off with a matte, it will reduce the amount shine and hotspot without losing any of the polarization properties. So, I hope this is true once I try it out for myself.

Thanks for showing me those links for the polarizer filters. I won't be spending too much on the filters right now, maybe in the future. So I'll be looking for cheaper but good quality polarizers like the one from Edmund Optics. Did you try these ones out as well? How do they compare with the ones from API?

I've also read about polarizer filters heating up and melting or even cracking due to the heat from the projector. But it seems that Jahun from, viewtopic.php?f=26&t=509 is using polarized filters used for photo cameras and rates them as superior for 3D. This is one reason why I'm stalling to buy cheaper polarized sheets when I can buy well made optical polarizer filters that have 'superior' quality. Maybe Jahun can comment on this.

I did quite a lot of research on which projector to get, not only for 3D viewing but as well as 2D viewing. And after that extensive research, I found that the specs the companies write down about their projectors are always quite wrong. Even though the specs say the HD7100 only has 1000 lumens, it's been reviewed and noted many times how bright this projector really is. So, I'm not too worried about that. I've also reviewed your HD71 and that projector is very bright and probably awesome for 3D, too bad you don't have two of them :).

Again, it's too bad your DIY silver screen never worked out. I'm still interested in seeing your pictures. But I'm really hoping I can find a cheap solution with some great results with minimal ghosting. I'm prepared to do quite a bit of testing and I will post up my progress.

Cheers,
Varinder
Author:  sharky [ Thu Jan 08, 2009 2:49 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
here is my setup.. its quite expensive but it works great and you will be satisfied since its almost the top you can have for home cinema.

projector:

2x hitachi CPX5 LCD 2400 lumen 90° output angle (very good for small rooms) ---> 702 euro each

filters:

2x SPAR filters ----> 540 euro each

silverscreen:

2x1,8 meters -----> 400 euro

glasses:

linear polarized ----> 4 euro each

this is all without shipment and vat. the prices are all quite old except the projectors wich include vat. all the other prices are from may more or less.

again, only a high quality setup gives a high quality result.. i think tril, likay and others can confrim since they all went for a good setup at the end.. :D
Author:  Tril [ Thu Jan 08, 2009 3:59 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
Not completely for me. My initial plan was to use two EP739 bought cheap because they were recertified. I bought two but one of them broke just after the end of the warranty and just before I got my screen. After that I bought the HD71. I tried to use the two together but the EP739 is holding back the other projector too much. I have to turn down dramatically the brightness on the new projector if I want to use them together. I can use them together if I want and I tried it once before but I don't do it anymore. It's not bright enough and I prefer a setup that's always ready to use without any setup time. That's why I got an iZ3D monitor.
Author:  Likay [ Thu Jan 08, 2009 12:51 pm ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
I can confirm Sharky's impression about a passive rig. It's convenient because everybody who wants to watch only needs a couple of polarized "sunglasses". Iz3d stylish ones works good but those dorky themepark ones have better ghostingrejection. The difference isn't too big though. Myself i use clip-ons because i use ordinary glasses.
The rig: 2000x1500mm 100" silverscreen from silverfabric (now awater3d), stereopol filters designed for lcd-projectors with 75% light throughput (SPARS as Sharky have) and two hitachi cp-x260 2500 lumen.
I always run the projectors on low noise setting (2000 lumen) and the 100" screen is still as bright as a normal lcd-screen! Wish i had room for a bigger screen since there's plenty of light for it. :oops:
Regarding ghosting rejection i've compared my rig with the one in the themepark "Liseberg" in Sweden. There's also an imax in Stockholm (cosmonova) but i haven't checked it. The ghosting rejection is better with my silverscreen than the screen in the Liseberg themepark. That screen has a special design though: It's made of metal and in a sort of "beecake" pattern (full of holes in it). Probably to let sound through or something. This could be very well be the cause of a slightly worse ghostingexperience. I don't know if every imax cinema uses such screens.
If someone wants to try passive polarization (you have two projectors) you can try buying some cheap rustpaint as mentioned in some thread and simply use ordinary polarizerfilms. If you don't have polarized films you can find it in trashed lcd-monitors or order from polarization.com. Beware that you're still are going to need some amount of light. With standard polarizers you'll have a maximum of 45% light throughput through the polarizer! The special SPARS-filters have a lightthroughput of 75% but works ONLY with LCD-projectors!. If i'm not wrong Sharky's filters might have even better values than the ones i have. :D
One other big advantage with passive rigs is that you need two standard left/right signals for it. And almost all stereoscopic softwares supports that natively. In these times it's priceless!

Relativity of lightexperience with different projectorsetups:
With dlp-projector and shutterglasses you have maximum 22.5% light throughput to each eye! This is because the internal polarization of shutters (shutterglasses uses lcd-crystals in combination with polarizing foil) efficiently steals 55% of the light and both eyes have to share the rest.
Dual projectors with standard polarization foils have 45% light throughput. Since each eye have it's own projector the lightexperience is doubled compared to shutter/dlp.
Dual LCD's with stereopol filters have a lightthroughput of 75% to each eye! Gaming with 2x2000 lumen on 100" in fully daylight causes no problem. Thought it's nicer if everything is lit out so the screen almost totally disappears! :D

Backsides with passive projection: Expensive. Parts are expensive. Projectorbulbs arent cheap either.
Projectoralignment is said to be a backdraw but if you ask me it's part of the sport. Once when learnt the important things with aligning the zoom/keystone and by using a testpattern made for this purpose it takes 5 minutes to get it right! The rig is sort of "portable" and i have used it at a few other places than my home. :D
Another drawback is simply projectorusage. It's not healthy for the lamps turning them on and off often for small amount of times.
For this i have an iz3d for occasional gaming.
Some says passive rigs ghosts... Well: It ghosts more than a dlp/shuttersetup but the ghosting with a passive rig causes no problem even with very high contrasts. So as i see it it's no problem and no use chasing higher numbers for ghosting rejection. ;) The big point of passive rigs are that it's simplicity for use when several people are looking and most of all the light emitted to the eyes.
For me building the rig was like fulfilling a dream. I gamed with shutterglasses/crt by the time and was really interested in going a "shutterless" system way. I had great plans in building a planar polarized rig but a visit in that themepark had me on other ideas. :D
Author:  ignatius [ Fri Jan 09, 2009 12:31 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
Hey guys,

Thank you so much for the feedback, really appreciate it.

Unfortunately i can't buy an lcd projector and purchase the very expensive SPAR filters it seems to go way over budget. However, this setup I'm building at the moment is a temporary one and I will only be keeping it for maybe a year or so. Afterwords, I will be upgrading once again to a pair of 1080p projectors or possibly a single 1080p projector that can project 3D images. Or a pair of LCD projectors using the SPAR filters if there still rated as one of the best methods for viewing 3D in passive polarization. The year of 2009 is going to be a great year for 3D and I'm aware of a lot of different companies and new displays coming out. So i'm guessing in a year there's going to be a lot of great 3D displays to choose from.

But for now, I'm just going to settle with dual 720p's using dlp projector and if i can get even reasonably good 3D effect using the passive/polarized method with a DIY silver screen. That would be more than enough for now. If the shutter glasses are able to show 0% ghosting, I would be happy with a projector display that even displayed 20% of ghosting compared to the shutter glasses.

At the moment, I bought a number of different silver materials, paints and fabrics to test out. Since i don't have the 2 projectors yet or any proper polarized filters. The way I am testing out the quality of the silver material. Is by pointing a flashlight through one of the polarized glasses i have (i have both circular and linear 3D glasses on hand) and pointing it at the silver material and then seeing the effect with another pair of polarized glasses to see how well the extinction level is works with the silver material.

I have a question though, since i'm not sure how well this method works for testing ghosting and extinction for polarization. But how black or opaque should the 3D glasses be when the light comes back from the silver screen? Should it be almost completely dark or is it ok for a little light to pass through?

Cheers,
Varinder.
Author:  ignatius [ Fri Jan 09, 2009 4:37 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
I've also just recently found a very good cheap projector that is better than the Optoma HD7100. But the only downside is that it has no lens shift. It has the digital lens shift, but i heard that's terrible.

Sharp XV-Z3000 -http://www.projectorcentral.com/sharp_z3000.htm
or
Optoma HD7100 - http://www.projectorreviews.com/optoma/hd7100/

Should i sacrifice quality for lens shift capabilities? Is aligning the two projectors really that big of a hassle?

Would appreciate anyones suggestions.

Thanks,
Varinder
Author:  Tril [ Fri Jan 09, 2009 5:51 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
I have experience with aligning an Optoma EP739 with an Optoma HD71. They both don't have lense shift. I use the projector holder I made to align the projectors. I leave the digital keystone adjustment off on both projectors. There is a slight keystone effect but it's small enough that it does not matter. I usually used the text of the icons on the desktop while I set the video card to clone mode as a guide to align the projectors. It might be better to use a test pattern instead but I did not bother finding or making one.

One thing that you have to take into account with projectors without lense shift is that when projecting from a high position, they are made to be hanged upside down from the ceiling. If you want to place them on a shelf high up, you'll have to place them upside down and you won't have access to the buttons on them. That's when the remote control comes in handy but since you have two identical projectors, it's a bit impractical (if you want to change the settings of only one of the two) as they will both respond at the same time.
Author:  Likay [ Fri Jan 09, 2009 9:39 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
I don't have lenseshift on my beamers so i have to, and uses digital keystone correction on my projectors. There's not a big deal of "pixellines" because of this but i run the games in native 1280x960 when the projectors native is 1024x768. This makes any rests disapear though.
To minimize the keystone phenomena you should mount the projectors as close to each other as possible. Have chilling of the projectors in mind so you don't interfere with that!

If you don't use keystone correction the image shown from the screen looks diagonally curved, like a bent sheet. It's no big issue and in the beginning i actually thought the effect was cool! :D The effect is less when you turn on 3d though.
I would definitely say that usage of keystone better that being without though. Lenseshift is the best since you're able to use the projectors native resolution (sharper picture) but might take more time to get right depending on how easy it is to adjust.

If you want to try different materials regarding preserving polarization the best thing is trying to project an image with polarized light on it and you'll also see how it actually looks like.
Author:  ignatius [ Sat Jan 10, 2009 1:08 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
Hey guys,

Thanks for the feedback once again. I'm glad not having a lens shift option with the projector doesn't seem to be that big of a deal. But a few experts with projectors still preferred the HD7100 over the Z3000 projector (for 2D viewing). So, I guess I'll still have my lens shift capabilities if I go with the HD7100.

After working on a lot of 3D content, I've also learned that the keystone effect is a major NO-NO when it comes to 3D. So I will be trying my best to avoid the keystone effect while projecting the images.

I'll also give an update on my progress with creating my own DIY silver screen. Even though i still do not own dual projectors and proper polarizer filters to accurately determine the quality of the polarization properties of the silver materials I have been testing. Using 2 linear or circular polarized 3D glasses seems to be doing a pretty good job at detecting the amount of polarization/extinction level of the silver materials.

I have yet to test out a couple of metallic aluminum paints i bought. But I did buy a number of silver reflective fabrics to try out from a bunch of local fabric stores. Using my very simple 3D tests, the results were quite surprising and I learned a few things that may or may not have been so obvious.

Out of all of the silver fabrics I found, the ones that showed the best results were the ones that were very flat and had no textures. I will have to go back to the fabric stores and ask them what this type of material is called and let everyone know. But the closest description i can give is that it's sort of feels like leather, except it doesn't have that rough surface instead it's incredibly smooth and flat. Surprisingly enough these fabrics didn't seem to produce a very SHINY effect either, it had a very matte look to it. So that's a major plus. And because it was nice and flat with no textures, that's another plus when it comes to projecting images onto this screen because there won't be any 'noise' coming from the silver fabric onto the image which would be incredibly distracting. I will take some photos of the materials I'm testing as well as their specific names so people won't have to go through all this trial and error. Or at least they can have a good start when making their own DIY silver screen. I'll post those up soon I hope.

I'm testing out the paints I bought right now and I will let you guys know how that went. There's one particular silver paint i got which is made by a company called Rusto-Leum (Tremclad) and it's an Aluminum rust paint. I've read at a number of different places on the net and a lot of people seem to have had very good results with this. One person in particular wrote down a very descriptive method of applying this paint that you can find here.

http://tech.groups.yahoo.com/group/phot ... sage/53419 (you may need to create an account to see the thread)

If someone doesn't mind doing a small test for me to determine how well their silver screen works by the method I'm using right now. That would be super helpful. All i'm doing is grabbing a pair of 3D glasses and holding a flash light behind it, and wearing the other pair of glasses and I simply rotating the 3D glasses in my hand to see how much the light is getting blocked with the polarized glasses. I tested this in a pitch black room to get the best results. I'm very curious how well this method works or not. If i were to rate the amount of light that gets blocked in one of the lenses with my best fabric, it's probably about 80-90%. I think that's pretty damn good with a piece of fabric found at some local fabric store. However, I have no idea how valid this method is in determining the effectiveness of the silver material. Not only that, but i can't even see what kind of negative or positive effect this may have on the image itself. Hopefully someone with any experience comment on this.

I hope to get a couple of dual projectors and proper polarized filters to test out the silver material properly with a 3D image. But for now, this is the best i can do.

Cheers, and sorry for the long post.
- Varinder
Author:  Likay [ Sat Jan 10, 2009 7:20 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
According to your test: I found an old thread about ghosting on different rigs:
viewtopic.php?f=3&t=861&start=20
This is with the rig i have.
Author:  ignatius [ Sat Jan 10, 2009 5:02 pm ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
Hey likay,

Thanks for showing me that link. Looking at your screenshots on that thread, if that's the amount of ghosting you see that's really good. That was projected on the silverfabric using the SPAR filters correct?

I'm so curious how much worse the silver fabric's i found and some cheaper filters would compare to your setup. Even if it were slightly worse, I'd be a happy duck.

-V
Author:  Likay [ Sat Jan 10, 2009 6:17 pm ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
Hi! :D
Yes: That is/were what i'm using.
As said: When ghosting is down at this slight amount there is no actual reason trying to push it down any lower. Ghosting rejection should be better with active good dlp-projector+a good pair of shutters. However: Shutterglasses are never ghostless either! To have similar light as from a passive rig from a single projector with shutters require an really strong projector and there you blow the economy anyway.

You don't need spar filters (lcd only!) to have this good ghosting rejection! The reason to use spars is mainly to have a brighter experience! Use a couple of high quality polarizers if you want to go cheaper at a start (like those in lcd-monitors if you're able to find trashed ones). Also: Lcd-projectors works great with ordinary polarizers if you plan to eventually upgrade your filters at a later time.

The needed thing for lcd-projectors is that the polarizers need to be aligned at 45° angle as the one the lcd's are having. Unfortunately it's not possible to use lcd's without filters because the colors are aligned differently. For example: If the color red is aligned at 0° the green and blue are aligned at 90°. If you align the polarizer 45° you still get an equal amount of colors (red,blue and green) to the eyes. Therefore lcd's actually works great using standard polarizers as well! :D

If you aren't using too shitty polarizers ghosting will be caused mostly by the silverscreen! (in other words: The silverscreen is the most crucial part!)
Myself i'm curious of what results are with those paints (screen-goo and aluminium rustpaints) available compared with silverscreens. I haven't tried but these should be very good option for diy's! It's easy to upgrade both to a screen and/or filters later on.

Edit: Linear vs circular polarizers.
I've tried both circular as well as linear polarizers and circular ghosts significantly more than linear. It's not a massive difference but there is.
It's said that circular polarizers/glasses allows you to rotate your head without loosing polarization ratio. This is only true to a certain degree. Circular allows slightly more tilting than linear but don't count on anything more than a few degrees! When playing stereoscopically where the content is rendered in a horisontal axis you need to have your head aligned horisontal as well to preserve correct impression. Try viewing anaglyph or with shutters and you'll see what i mean. Basically i'm trying to explain that being able to tilt you're head more is of no use viewing stereoscopic content without a headtracking device that also registers headtilt.
So: Linear polarizers are more common, easy to get, cheaper and works way better than circular filters. Go linear!
Author:  Tril [ Sun Jan 11, 2009 12:06 am ]
Post subject:  Re: Home Theatre 3D Stereoscopic Projection + DIY Silver Screen
Here's my thread about my attempt at making a passive projection rig : My DIY attempt at building a passive projection rig. I posted the paint tests I did. The results are not very extensive but that should still be a little useful.

The second post is an old post I wrote last year but never posted. It's not up to date but it might still be an interesting read. Since then, I bought a Da-Lite screen.
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