[REQ] Curved Projection Screen

[Raptor007]

Hey, first of all I want to say hello as this is my first post here at MTBS.

I have been mocking up a single projector curved screen 3d system for a couple weeks now for flight sims and general use.

I want to use rear projector to project onto a 120 FOV curved screen.

-------------List of Equipment:------------
nvidia geforce glasses for the 3D
custom built rear projection screen
TrackIR 4 Pro

From http://www.3dmovielist.com/projectors.html
Infocus X3 or maybe Sharp XR-10X if I can find it cheap
-------------------------------------------------

Using the Sharp XR-10X, I am looking at about a 7' distance behind the screen to get a 8' by 6' screen curved to 49" cross-wise. I have seen some simulators reflecting a projector off a curved mirror onto the front of the screen. Such as http://www.mycockpit.org/forums/showthread.php?t=1164.

Has anyone used such a setup to view anything in 3D? I am wondering if the distortion caused will totally mess up any chance of viewing in 3D.


Also I haven't found anyone to try to use a concave mirror (as opposed to the convex on in the previous link) to project onto the back of a screen. Has anyone tried such a method and will there be any distortion that will cause 3D not to work?

Thanks for any help! I have been addicted to these forums, much to the chagrin of my boss...

[Okta]

Hi im kind of in the same boat as you. I have a Xr-10x and was looking to make a curved screen and your link is great. I had not thought of a curved reflective surface to correct for the curved screen. I had an idea i posted in another thread to try camera lenses on the projector to warp the image for a curved or dome screen but dont have the expertise or resources to test.

This link here shows using shower curtain as a rear projection screen so that is one hurdle overcome for testing.
http://cmpalmer.blogspot.com/2006/08/re ... oject.html" onclick="window.open(this.href);return false;

I was considering doing a slightly curved rear projection setup and ignoreing the distortion in my peripheral view (sides) like the jdome. Just a slight curved at the edges would add tons of FOV i think so you wouldnt need to make the screen too large as you can view it from a few feet. This will also help brighness and reduce the distance the projector needs to be from the back of the screen.

My real biggest problem is i dont have a spare room to set up my projection rig and experiment

[Raptor007]

A shower curtain seems like a great idea. I had not thought about what to build the screen out of yet, but something that cheap would be a great fit.

I am guessing that with the curved mirror you wouldn't get any distortion on the edges of the screen since the mirror distorts the image for you. I have heard that a flexible plastic sheet covered in mylar mirror material works well. You can buy it from large plant supply stores. Used to reflect light onto the plants.

I am running into the same problem with space though. The mirror can half the throw distance you need which helped me a lot. Squeezing a full 7' would put it into my kitchen...

[martinlandau]

Raptor, here is something I was considering, a small dome to give a huge field of view. 20K USD for some of the professional domes is too much.

http://www.playerzblog.com/a-cutting-ed ... -dome.html" onclick="window.open(this.href);return false;

Even this dome seems to be more than you need, you could shrink it down and sit very close to it, it only needs to just be a few inches from your face to give wide field of view no?

The guy below seems to be the world expert for domes and immersive gaming, I have not had time to read all his papers, but maybe you can or perhaps you can contact him.
http://local.wasp.uwa.edu.au/~pbourke/papers/" onclick="window.open(this.href);return false;

We need to find a cheap screen material, a cheap curved dome mirror, and a cheap frame of some sort to mount the screen material too. Recently at infocomm all the dome solutions were front projection, but this will not work for a small dome right in front of your face. Perhaps you could mount a pico projector with extremely short throw distance and get a small dome front projection to work. What are the highest res shortest throw pico projectors?

[Tril]

Look at the arcade game of Gundam that uses a dome. It's front projection and the projector is on top of the head. It uses some fisheye lens to distort the picture. I've got no idea how you would do that at home. That's some extremely short throw for a projector there.

Here's a video where we see how large the screen fills the view.
http://www.gametrailers.com/user-movie/ ... tup/209062" onclick="window.open(this.href);return false;

[Raptor007]

Good find on those papers, I have started reading them. So far there are some great summaries. The first paper listed especially.

I have looked at some pico projectors in the past, but they were expensive and with a low resolutions and a low max screen size. With a quick check from some of the ones listed here http://www.fastcompany.com/blog/noah-ro ... to-gallery The resolution is still low at 800x600 SVGA. Plus even with the short throw I don't see how to position it to cover the screen without your head getting in the way.

The arcade game of Gundam did look impressive. Too bad the video didn't say how they did it. Or give more than 6sec inside. It looked like it was either a very short throw projector with some large correction for the angle, or there was more than one projector. I still want one though...

For the mirror something like http://www.filmtools.com/flexiblemirror.html would be a perfect solution. Since a "you can play god and literally reposition the sun's rays" <-- really from their website....


The Jdome is a rear projection system, http://www.jdome.com/. So something like that but with a mirror to remove warping in the X direction.

Still haven't figured out the screen. Shower curtain, bedsheet, silk cloth all seem like possibilities. I am worried about blocking out too much light between the rear projection and the Nvidia shutter glasses that it will be too dark though.

[martinlandau]

Raptor, here is another idea from another thread, but it applies here too:

halfway down this page, they say a spherical mirror is cheaper than a fisheye lens and better, what are your thoughts? It seems fisheye lenses are cheap.

http://www.icinema.unsw.edu.au/projects/infra_dome.html" onclick="window.open(this.href);return false;

Here is a guy who created "fisheye quake" which should mesh perfectly with all the quake engine games out there and a spherical or dome system.

http://strlen.com/gfxengine/fisheyequake/index.html" onclick="window.open(this.href);return false;

I had much more info to share, but IE crashed on me and took all my url's with it

I want something that is smooth and seamless, I am going to look around this week for a big clear sphere or half sphere, made of plastic or glass or such. Mountaint a sheet in some tent poles the way it looks like the jdome works will leave you with a few lines in your picture, I can't have that!!

[Raptor007]

That icinema system looked familar and sure enough at the bottom is a mention of Paul Bourke for the display. His paper about it is here that i read http://local.wasp.uwa.edu.au/~pbourke/p ... phite2005/. I guess there are some other ones since it looks like he is involved with iDome.

It seems like a good idea, But the fact that they mention image processing must be done to correct for the mirror geometric distortion has me worried. I would have thought that the mirror would correct for the curve of the dome. Perhaps they only have to change the image because of the way they shot with multiple cameras. If that is true it seems like such a mirror could be bought simply. The problem would be matching the mirror curve to your dome curve. You can't really adjust either so they would have to be purchased to fit, that could be tricky.

I have played Unreal in a CAVE system before and it was rather amazing, but it takes a huge amount of computing power to do any image modification. I am guessing the Quake would be similar in nature. I am hoping to be able to play modern games on my average computer.

Hopefully I can get a plastic mirror and borrow a projector from work to test out how the image looks sometime soon. I will post some pics when i get it working.

[martinlandau]

They use a 2 meter dome with a HUGE fisheye lens - I wonder if anyone can find the FOV specs on the Gundam POD.

http://www.gundam-kizuna.jp/english/game/index.html" onclick="window.open(this.href);return false;

I finally read a couple of those academic papers. You are right Raptor, it is very illuminating. I did not realize the jdome only offered about 100 FOV, still far short of the 180 our eyes can do and that the idome promises.

It seems from my readings that if you use the fisheye lens you don't need the extra post-processing step, but he seems to say that extra post processing for the spherical mirror is very minimally taxing.

[Raptor007]

So I turns out it is difficult to find a curved mirror. After all the basics were exhausted; Walmart,Target, then the hardware stores had nothing and told me to go to a plant nursery who told me to go to a hardware store. Even a custom home theater store laughed at me...

And for anyone reading this thread, a emergency blanket does NOT work as a curved mirror. Found one for cheap and thought I could get it to work. It comes so folded and crinkly that heat and stretching will not recover it.

I guess it is time to buy a mirror surface online and hope it works...

Martin if you find a dome of some sort that works for you let me know, I would be interested where you found one.

[Okta]

How about one of those big curved mirrors they mount on the corners of buildings near driveways so you can see traffic and pedestrians when coming out a of tight allyway? This will only work for front projection i suppose.

http://cgi.ebay.com/HAMMERSCAN-SAFETY-M ... 1|294%3A50" onclick="window.open(this.href);return false;

http://cgi.ebay.com.au/VINTAGE-CONVEX-G ... 1|294%3A50" onclick="window.open(this.href);return false;

http://cgi.ebay.com.au/Shop-mirror-conv ... 1|294%3A50" onclick="window.open(this.href);return false;

http://cgi.ebay.com.au/18-inch-Outdoor- ... 2|294%3A50" onclick="window.open(this.href);return false;

[Raptor007]

I had seen a couple of those curved mirrors online for security. I think the tricky part would be matching the dome with the curvature of the mirror. You could set it up very similarly to one of the papers mentioned before though.

I found this though http://www.collectionsetc.com/Stick_on_ ... tid=410161
Rather cheap and should be able to test some reflections.
PROMO CODE "3F9276" gives cheap shipping too. Should be in next week sometime and I can continue testing.

[martinlandau]

First read this:

http://local.wasp.uwa.edu.au/~pbourke/m ... r/faq.html" onclick="window.open(this.href);return false;

He talks about using a 60cm spherical mirror source here: http://www.acrilconvex.com/firstsurfacemirrors.htm" onclick="window.open(this.href);return false;

Then go here:

http://www.observatorycentral.com/index ... owforum=58" onclick="window.open(this.href);return false;

Above is a bunch of planetarium buffs who built home domes, why re-invent the wheel?

http://blog.makezine.com/archive/2009/0 ... _dome.html" onclick="window.open(this.href);return false;

Above is another idea.

Raptor, I did a froogle search:

Mirrors:

http://www.technologylk.com/catalog/74/ ... e-Mirrors/" onclick="window.open(this.href);return false;

http://www.randmh.com/mirrors/" onclick="window.open(this.href);return false;

http://www.gordonglassusa.com/group/57/ ... irrors.htm" onclick="window.open(this.href);return false;

http://www.globalindustrial.com/gcs/gro ... Groups.web" onclick="window.open(this.href);return false;

Domes:

http://www.fsiweb.com/domes.asp?gclid=C ... 7Qod01WZBQ" onclick="window.open(this.href);return false;

http://www.spitzinc.com/domes/premium_seam.html" onclick="window.open(this.href);return false;

http://www.projectdalek.co.uk/files/autopsy/dome.html" onclick="window.open(this.href);return false;

http://univfoam.com/" onclick="window.open(this.href);return false;
I was originally thinking about finding some of those old large satellite dishes that no one uses anymore. That is going to be heavy to move. Styrofoam is going to be light and cheap. You can probably get a big block of that stuff and make your dome for cheap. I have seen artists at the beach carve out sculptures from a big block of styrofoam. Raptor I don't have time to read the home planetarium threads right now, maybe you can turn up a few gems. Maybe this weekend I will have more free time. A few more links, but I think that Bourke FAQ at the top is going to have the most info.

http://www.tomsdome.de/blog/" onclick="window.open(this.href);return false;

http://www.desertdomes.com/index.html" onclick="window.open(this.href);return false;

http://lss-planetarium.ovh.org/index.ph ... ge=project" onclick="window.open(this.href);return false;

[martinlandau]

How are you going to build your dome? That is my biggest engineering challenge personally. I would like to find something already fabricated ideally.

In some of Bourke's papers he says to use a 3 meter dome as the smallest. He does mention Elumens visionstation at 1.5m, but says he doesn't really recommend it - but he doesn't say why. I would like to know why.

Do you have any ideas why a 1.5m dome will not be sufficient? Perhaps you can email him and get the answer for us, he says he is open to general questions from the public for personal dome building. I wonder if 1.5m is ok for a fisheye lens, but not OK when you start getting into spherical mirror projection, I wish he would clarify.

http://local.wasp.uwa.edu.au/~pbourke/m ... r/faq.html" onclick="window.open(this.href);return false;

What is the smallest sensible dome for digital fulldome projection?

This depends on the application, for single person domes I suggest 3m is about the smallest. The old visionstation by Elumens (no longer available) was 1.5m and while the spherical mirror has been used it isn't ideal. My dome shown below is 3m diameter but as you see it is orientated differently to planetarium domes.

Here is the elumens website showing information about the visionstation the Bourke talks about.

http://www.est-kl.com/aufbau_general/in ... ns/vs.html" onclick="window.open(this.href);return false;

http://www.vrealities.com/visionstation.html" onclick="window.open(this.href);return false;

System Dimensions & Weight:

Overall Height: 165 cm (5’ 5”)
Screen Height: 145 cm (3’ 11”)
Overall Width: 160 cm (5’ 3”)
Screen Width: 151 cm (4’ 11”)
Overall Depth: 94 cm (3’ 1”)
Screen Depth: 53 cm (1’ 9”)
Screen Radius: 81 cm (2’ 8”)
Surface Area: 2.4 m2 (26.0 ft2)
Weight: 42 kg (93 lbs)
Crated: 112 kg (300 lbs)

A how stuff works article on the visionstation and it's lens:

http://computer.howstuffworks.com/elumens2.htm" onclick="window.open(this.href);return false;

The f-theta lens has a hemispherical optical assembly that allows it to project over a 180-degree range.

TruTheta combines advanced, 3-D software algorithms with the f-theta lens design to enable high-quality projection on a hemispherical screen. The goal is to create images that are consistently bright, even and in focus. To accomplish the goal, the TruTheta lens distributes pixels equally throughout the hemispherical surface, eliminating distortion.


To create the 3-D scenes, Elumens recommends the four-camera process. You set up a scene in a 3-D-animation program as usual, with a single (main) camera following the animation. Once the scene is prepared, you duplicate the original camera four times. The other four cameras are rotated 90 degrees on the camera axis to point at different areas of the scene. The four additional angles are:

* Camera-left: The camera is rotated 90 degrees to the left of the main camera.
* Camera-right: The camera is rotated 90 degrees to the right of the main camera.
* Camera-top: The camera is rotated 90 degrees to the top of the main camera.
* Camera-bottom: The camera is rotated 90 degrees to the bottom of the main camera.

Once the frames of the animation are rendered from all four angles, a program called TruFrame is used to combine the four different scenes into a single scene that provides all the information necessary for 180-degree projection.


Finally a yahoo group that seems to be intersted in home domes, I don't have time to read all that info now, perhaps you can pull some gems from there if you have the time.

http://groups.yahoo.com/group/fulldome/message/561" onclick="window.open(this.href);return false;

[Raptor007]

Wow some good info there. I just wanted to post and let you know I am reading it, it will take some time though, lol.

I am not really building a dome, more like a cylindrical shell. I figured I would start with that and then go from there if the concept works.

The foam idea is a good one though. Home Depot has this pink insulation foam that you could glue a huge block out of then sculpt it into a dome. Maybe some paper-mache and a sanded high gloss paint to finish it off. Be prepared for a MASSIVE mess though, that insulation foam is a pain to work with.

[martinlandau]

http://citeseerx.ist.psu.edu/viewdoc/do ... 1&type=pdf" onclick="window.open(this.href);return false;

Ok did some more searching, here is the SPI (spherical projection) API documentation from elumens about their warping API for curved projection. It is not the best method according to this guy:

http://www.evl.uic.edu/files/pdf/Kooima-IPS2008.pdf" onclick="window.open(this.href);return false;

He goes into various ways of warp programming for curved screens. It has been awhile since I have done any programming, but he said the geforce 8800 series was a godsend - from the pdf:

In 2006 this approach received new life
with the release of the NVIDIA GeForce
8800, the first hardware to expose
programmable geometry processing. This
allows the primitive subdivision process
to be offloaded to the GPU, again freeing
the application to manage its geometry
normally and eliminating the performance
bottleneck.

Here are the folks that bought up elumens assets when they went bankrupt a few years ago - I saw these guys at infocomm recently, they had the panadome setup, it was slick!

http://www.immersivedisplay.co.uk/products.html" onclick="window.open(this.href);return false;
http://www.immersivedisplayinc.com/" onclick="window.open(this.href);return false;

The prices have come down, but they still want 10K for the entry level dome system, like Kurt Russel said in that movie USED CARS - Too Phucking HIGH!! LOL!

A public VR forum talking about warping API's and even some code for you to download, get while the getting is good!
http://forum.publicvr.info/viewtopic.php?f=15&t=52" onclick="window.open(this.href);return false;

He talks about warping in the unreal engine:
http://planetjeff.net/html/pro_vrgl.html" onclick="window.open(this.href);return false;

http://www.etc.cmu.edu/projects/dome/tech.html" onclick="window.open(this.href);return false;
These guys do to, they seemed to like the panda3d warping solution the best.

http://www.springerlink.com/content/900373u114u18602/" onclick="window.open(this.href);return false;
These guys say the omnimap API is the latest and greatest free warping software.

http://www.elumenati.com/products/omnimap.html#download" onclick="window.open(this.href);return false;
It seems to have directx10 compatability, you will have to fill out a form and download it, go get it for us and when I am back at my home computer you can send it to me

[kekewons]

Thanks again for that heads-up, ml.

It seems you have done a lot of web research the last few weeks (good man!).

I'll assume that is how you stumbled, too, into my thread over at LumenLab.com...yes?


k

[martinlandau]

Ok just to bring this thread up to date:

I met and talked with the guys linked below at siggraph, I told them about bourke for dome spherical projection and the people into flightsim at flightsim.com , and about the frex canopy gaming solution. They said they would contact them all time allowing, so perhaps very soon for those of you that are frex canopy fans, you will have a solution that will take care of the distortion at the edges, this tech helps fix that!! They are using a special LCD that alters the luminence channel making everything much clearer and the colors much better when projected on curved or other exotic surfaces.

Also the technology helps if you have a very short throw projector and sit very close and want to take care of the "screen door" effect that you see now in most settings. They slightly defocus the image to remove the "screen door" then using thier technology get most of the clarity and resolution back giving you an image almost as good as the original but without any screendoor! Practical application of this - think about the gundamn POD game pictures posted earlier in this thread, a short throw projector, and the user sitting very close to the dome screen, this will make it all so much more wonderfully beautiful!

http://www.gundam-kizuna.jp/english/game/index.html" onclick="window.open(this.href);return false;

These guys http://www.uni-weimar.de/medien/ar/research.php" onclick="window.open(this.href);return false; were showing off:

Adaptive Coded Aperture Projection

Displaying dynamic aperture patterns on a liquid-crystal array at a projector's aperture plane together with inverse filtering supports projector defocus compensation, high quality projector de-pixelation, and increasing temporal contrast of projected video sequences. Such adaptive coded apertures are a step toward next-generation auto-iris projector lenses.

Neil, since you are going to be doing new gaming display standards anyways related to s3d, perhaps you can work in warping of scenes into some game standards to project on domes or curves or that new curved LCD or wide screen gaming and such? I know in Oblivion I was able to alter my FOV settings, but I am not sure you can do that in every game?

[PalmerTech]

If I were to build a dome, I make a diagram of the final product, then figure out the curvature I would need on a 3 foot by 3 foot chunk. Then, use body filler and some ABS plastic, vacuform the shape, then use it as a fiberglass mold. From there, you could just make as many of the curved panels as needed, and they would all fit together with minimal fuss. Easy to make, perfectly curved, and lightweight.

It would be an excellent frame, all you would have to do is use some bondo body filler on the seams where it goes together, sand it down, coat with primer, final sand, and then coat the inside with projection paint.

As for the mirrors and such, keep in mind that the thickness of the protective layer on back coated mirrors is high, since they have most of their physical strength focused in that layer. By reinforcing the inside of the dome, you would gain the freedom to buff down the acrylic (easy to do with proper tools) so that there was only a very, very thin layer over the reflective surface. This way, you get good durability, and almost all the clarity of a front coated mirror.

Any thoughts?

[martinlandau]

Great stuff Palmer, start building, need for speed shift with wide FOV and a dome is going to be amazing I am sure!

http://www.mtbs3d.com/phpbb/viewtopic.p ... ome#p29165" onclick="window.open(this.href);return false;

Also I have contacted several plastics manufacturers so far you can get a nice dome screen here http://www.cleardomes.com/domes.htm" onclick="window.open(this.href);return false; for under 500 dollars that is 60 inch diameter that is as good as the old Vision Workstations dome that was costing 20,000.00 Perhaps some members here can find a source for even cheaper small domes?

Although bourke's ideas of using spherical front surface mirrors are very cheap, I was planning on taking prototype version 1 all over to various conferences, so durability was important, so for the first version I was planning short throw stereo3d projector with fisheye lens like the Gundam Pod above. If you need some diagrams, search for vision workstation dome, company is bankrupt now, but you can still find their diagrams online.

http://www.google.com/#hl=en&q=vision+w ... bfff7f9103" onclick="window.open(this.href);return false;

http://www.vrealities.com/visionstation.html" onclick="window.open(this.href);return false;

http://www.freepatentsonline.com/6712477.html" onclick="window.open(this.href);return false;

[PalmerTech]

Interesting.

What kind of 3D projector would you be using? I assume it would have to be a DLP with shutter glasses?

What are the pros/cons of a fisheye setup vs the mirror? Is it possible to compensate in most games, or is that something that is yet to be worked out?

Also, are you going to buy that dome, or build your own?

[martinlandau]

My hope was a specially built iz3d projector that blackq said may be possible because they are not limited by the same case constraints as the monitor solution and BLEEP - proprietary stuff not to be divulged in public! Banning that, a short throw dlp projector for now with shutter glasses - viewsonic has a short throw s3d one that should be out just around the corner now, but a polarized glasses solution is my dream. The only real pros and cons is the fish eye probably won't be getting scuffed and damaged as easily as a front surface spherical mirror, but it costs much much more. If it was just for home use, I would go with the bourke spherical mirror solution and save all that money. I expect kids and lots of people to be getting in and out and being around the machine and I just see a fisheye lens mounted over your head ala the gundam solution above as more durable. The distortion is the key issue right now Palmer. Most of the newer generation video cards can do the geometric compensation pretty easily in the hardware, I posted about that somewhere here. But in the old days the visionstation folks had some special warping software to do it - wouldn't work today with the high framerate high rez games. Read some of bourke's stuff at his site if you would like some great info on how he is using blender and 4 90degree FOV's to do the warping onto the dome. Also check out the "fisheye" quake stuff I posted here if you want to do some quick testing at home - but that creates six different 90degree FOV's - you only need 4 and the author of fisheye quake confessed that to me. He said he wanted to see behind him

No I already bought that dome, and the motion simulator, but last weekend I was hauling the motion simulator down the highway and got rear ended and went to the hospital and the motion simulator is in motion simulator heaven now ;( But I am hoping the insurance will replace it but that still destroys all the marketing efforts I had big hopes for at dragoncon and s3dga at the 3d entertainment summit this year.

If you are going to try and build a dome cheaply, some of the people over at http://www.avsforum.com" onclick="window.open(this.href);return false; told me about this material at home depot - you use it to line your bathroom walls with - you could just cut the sheets in the right way and have a pretty good dome - but I think your DIY solution is much better than what they were describing. If you have the time, I think that is going to be the future of gaming, I know it excites the hell out of me after reading that leep VR stuff to get a full FOV stereo3d gaming solution going.

[PalmerTech]

Where did BlackQ say that? Last time I saw him responding to a projector query, I noted that you interpreted his response as optimistic, when he was actually being pretty grave; But seriously, I would give up hope of an IZ3D projector, the tech is just not feasible. Sorry. It is possible with these large 17"/22" panels, but projector sized panels are not going to happen.

Do you have a link to that material for the domes? I would be curious to know what it is. Sorry to hear about your accident.

One more question: What exactly is expensive about the fisheye solution? The fisheye lens?

[martinlandau]

Palmer this the last thing I remember blackQ saying on my iz3d projector thread publicly - he also tell me many things privately but I cant divulge that or maybe he own my soul with lawsuits cause it was all kinds of proprietary military stuff maybe

http://forum.iz3d.com/viewtopic.php?t=1 ... sc&start=0" onclick="window.open(this.href);return false;

BlackQ
Chief Annoying Officer

Joined: 07 Oct 2005
Posts: 2458
Location: Airplane

PostPosted: July 14, 2009, 12:18:25 AM Post subject: Reply with quote
btw - splitting light path within projector may be more effective implementation than "internal" iZ3D.
_________________
Who is John Galt?

Where did BlackQ say that? Last time I saw him responding to a projector query, I noted that you interpreted his response as optimistic, when he was actually being pretty grave; "

I am drunk on sake right now l( can you point it out, I am sure it is there, I just don't remember BlackQ getting negative with me on my iz3d projector thread only on my dragoncon thread. I am kinda positive guy - maybe I need to reread it with different perspective.

"But seriously, I would give up hope of an IZ3D projector,"

I am not give up hope kind of guy, there was once this guy called cyberreality and he said ABANDON ALL HOPE YE WHO ENTER land of modifying iz3d monitor with collimated light, but then you came along Being hopeful pays off.

" the tech is just not feasible. Sorry. It is possible with these large 17"/22" panels, but projector sized panels are not going to happen. "

BlackQ is top russian physicist that can build nuclear bomb out of macgyver DVD and some bubblegum, and he got OLEG who is gravity wave expert genius and can make time go in reverse and change author of "the time machine" to alan smithee - why wouldn't you believe they are possible of ANYTHING they put thier mind to? with BlackQ - the world of dreams is your oyster and his gobs of high tech russian scientists doing things maybe no one here in the USA know about for years - I think he was inventor of trinary computing - as Boney M say - those darn russians! LOL! And now NASA shutting down the shuttle program so we can rent spacetime on russian spaceships - WAY TO GO USA! LOL!

"Do you have a link to that material for the domes?"

Everything I found is posted somewhere on mtbs3d, or maybe a google search will help, I am just so tired and about to take another vicodan for pain. I will try to look tomorrow if you can't find anyting, but now I need rest.

"Sorry to hear about your accident. "

Thanks Bro, I am just happy to be alive! God has a plan and I trust his judgement.

"One more question: What exactly is expensive about the fisheye solution? The fisheye lens?"

Yes, maybe you have friends in china who can get stuff cheap though, that current viewsonic s3d dlp projector - see how much you can find fisheye lens that will interface with it. I was thinking thousand dollars from rough estimate.

[martinlandau]

http://www.mtbs3d.com/phpbb/viewtopic.p ... eald+clone" onclick="window.open(this.href);return false;

What do you think Palmer? I always have backup plan B and C and D sometimes too

[PalmerTech]

When I meant negative, I meant using the "IZ3D method" of dual LCD panels with different polarization. He pointed out it would have a mere 0.04% light transmission rate with such small panels, you cannot just take the current tech and make it into a projector. If they did what he said and used a split lightpath, it would be awesome. I have a custom laser combiner, it uses a series of mirrors and lenses to take two laser beams and combine them into one, I imagine building a larger one with dual projection panels, each on a different polarization rotation, would be the way they would do it.

So see, I am not being negative, it could be made by them and use their driver, but it would certainly not be the current tech they are already using in their monitor. In fact, a DIY version of it is possible...

And I think I found the film we need, it uses micro-prisms to focus the light forward, and recycles almost all reflected light as well. I will try some in my IZ3D monitor as soon as I get some sample sheets.

I will try and find some cheap lenses. I also posted in your other thread.

[martinlandau]

Sounds great Palmer, I am excited by your enthusiasm. Get BlackQ on board over at iz3d and maybe he sponsor you and give you big job with OLEG and Aaron Rapp. They have offices in california, not far from you probably, why not pay them a visit?

[PalmerTech]

Ha! I will do that after I actually make some progress, at the moment, I have not even used my screen!

[BasementScientist]

I don't know if this thread is still active or not, but here's my idea.

Instead of having an actual dome, why not have a curved section of a dome spinning around you.
If it's fast enough, it would appear solid. Could use more than 1 slice to lower the speed.

Probably would be too dangerous, plus if you can build the sections, than you might as well just build all the sections and piece them together.

[Raptor007]

A+ BasementScientist for some outside the box thinking. Even if it would end up with some severe limb trauma.

As an update I just bought an Optoma HD66 project that arrives on Monday. I own the mirror and need to make the curved screen. I will put something up here if somehow I get the 120deg curved screen to work.

[cadcoke5]

There has been a bit of discussion about this on another thread. [ http://www.mtbs3d.com/phpBB/viewtopic.p ... 0&start=15" onclick="window.open(this.href);return false; ]

I had a thought related to some research done by SIFAT. This is the Southern Institute for Appropriate Technology, a Christian mission organization that seeks to educate and develop technology for 3rd world countries. They were researching ways to make a solar cooker. One idea involved a Mylar film that was put over a frame and then a vacuum was applied. The ended up abandoning the idea, since they couldn't maintain the vacuum over a long period of time. I will mention that they also abandoned solar cooking entirely, since none of the projects really turned out to be more than a food warmer or dryer. It seems a lot of alternative energy ideas are like this... fun to play with, but in the end they just aren't practical.

Back to the topic. For us in developed countries, a small electric fan to generate a continuous vacuum is not a problem. So, a dome can be generated by simply mounting a somewhat stretchy material to a round frame. If the frame has a tent-like structure behind it, and covered with non-porous material like vinyl, then you can use a fan to suck out some of the air. The screen material will be sucked into a dome shape.

But, the big question is how much of a dome you can expect from such an idea. Regular vinyl projection surfaces may not deform enough. A rubber like sheet would be idea. Lowe's sells a Shower Pan Liner, Item #: 20088 , for $27, it is 5'x6', but it is gray. I don't know if something like this can be found in white or a lighter gray. Another idea is a large weather balloon. An 8' balloon can be purchased for around $25. They are white , but are quite translucent.

Another obvious material to think about is the nylon used for outdoor holiday inflatables. Kite supply stores sell the cloth. However, since it doesn't stretch, it would have to be sewn, and would not form a perfect spherical surface.

For the frame, I imagine the easiest is to use electrical conduit,and a pipe bender. The circle may not be perfect, but I don't think it has to be. I have attached an image from an AutoCAD drawing. (Can you tell I am unemployed and looking for stuff to do?)

For projectors, I wonder if the current, or soon to be available lineup of ultra-short throw projectors are viable for this type of application? Some of these are using a curved mirror to accomplish their wide projection angle.

Joe Dunfee

Dome Frame.jpg

[cadcoke5]

BasementScientist, I had actually done some calculations for your spinning display around a person some years ago. It was actually to put the image on the outside of the person. But, I can see it for inside as well. However, the reality of spinning something that fast was unlikely to make it viable. There are LED ropes that have individually addressable LED's, but they are not very dense in terms of pixels.

Lets say you had 4 of these LED ropes spinning around you. It would be like a jump-rope, only horizontally instead of vertically. if you need a refresh every 60 seconds, then one of the ropes must pass your gaze every 6 seconds. So, the 4 ropes would reduce it by 1/4. Each rope must go around you at 15 revolutions per second = 900 RPM.

Joe Dunfee

[mikemav]

I've been thinking of building a triple-wide screen going to 3DV Surround now that drivers are out, w/ rear projection for center section, using a short-throw Nvidia 3D Vision capable Optoma GT720 projector. For the side screens flanking it I'd use either the same or a similar Optoma HD66 which has a longer throw and zoom lens. These would be mounted behind the user above. This is for a mostly racing car simulator. I originally thought to do a curved screen, ala the Red Bull Formula One Team's official sim:
http://www.youtube.com/watch?v=rE-Fge3gN9w" onclick="window.open(this.href);return false;
But, edge-blending and image warping three cheap projectors across a curved screen will be quite a challenge and end results may be more distracting than using three separate flat screen surfaces, the outsides angled in, and maybe even a slight bezel in between to give the eye a distinction point so as to not focus attention on the differences between the three images. Otherwise there are hardware or software solutions to edge blending the warping, but all cost a significant portion of the budget ($300-2000k) just for solving the warp/blend issue. I work for a pro-AV firm and know my way around projection and high-end systems. I have a client who tried to mock together something similar with three short-throw projectors (not in 3D), and even though they used a flat triple-wide screen on a flat wall, they were not satisfied with the projection overlap/blending w/ their software solution.

Anyway, the big issue I've been thinking about is field of view w/ 3D Vision. I currently use a 60" Mitsubishi DLP set with 3DV in 1080p resolution. It sits close to my seat and takes up a good percentage of my FOV. The issue I'd think might be present going wider is peripheral vision while using the Nvidia shutter glasses. While I can see about 180 degrees, there is a drop off where the edges of the glasses are which is much narrower. Maybe 100 degrees? I know for example w/ my 60", I could never put two more 60" to the sides of the current one and see all through the 3D shutter glasses. I'd have to go quite a bit smaller, even if they were angled in similar to how a curved screen would be. Wouldn't it be distracting to see 1/2 or more of the outside images in your peripheral vision NOT w/ the shutter glasses covering them? I'd think it would flash annoyingly or something in the corners of your eyes where the glasses don't cover. So I may mock up something more like triple 45" size or so to see if that might work. Really what we need is 3D Vision goggles or wrap-around shades (Oakley style) that cover a wider FOV.

Anyone have any ideas? Or does anyone know of any threads online, here or elsewhere, where people already have set up triple projection w/ 3D Vision Surround? I wonder if in 3D they have seen this issue?

[Goldtoes68]

I got this curved projector screen: https://www.projectorscreen.com/store/p ... creen.html. I've been very happy with it.