Gaming Room Circular Projection Build Log

Post by **BHawthorne** » 13 Sep 2009, 06:35

With up to six display capability now I thought I'd start a thread covering one of the more "out there" concepts -- a circular projection room.

The ATI dev guys were babbling a lot about first generation "holodecks" in the next decade...well frankly with 6 screen output that is technically something that could be done now on consumer systems.

A few of the speedbumps on the way to a functional first gen "holodeck":

Circular projection requires pre-warping to conform to the circular geometry of the screen. At this time there is one consumer solution for this, ImmersiView's Sol7 Simpit Edition. It handles pre-warping and projector edge blending. That'll allow you to properly project onto the screen without distortion occurring.

Short throw projectors. This is a large roadblock for me right now. I own 3 InFocus SP5000 and if I want to throw a projection full wall height it requires a throw distance of approximately 16 foot. That simply doesn't cut it. The projections chosen to do some circular projection setup like this require short throw lenses. If anyone has any suggestion for cost effective short throw projectors, please post them.

Screen design. We just can't go to Walmart and pick up a circular projection screen. Noone sells them to regular consumers, or if they do it's at crazy prices. This almost guarantees that the screen has to be scratch built. I've seen instances of people selling bulk screen material on ebay and other places. I'm sure there are fabrics and other materials in bulk roll form that would be ideal for this. Suggestions?

LED projectors. Use a projector type that has an LED projector bulb with a 25,000 hour+ bulb life. There is no way I want to be buying 6 projector bulbs at $300 each every 2000 hours. That's not gonna happen. :wink:

720p vs. 1280x1024 vs. 1080p and 3/4/5/6-projector count. What is the math here on just how wide the FOV and circular screen covers? Can we pull off 180, 270 or even 360 with just 6 projections and not need any special mirrors to warp the projections even wider? What kind of FOV are we looking at with these particular configurations?

Things not taken into account? I'm sure there are a bunch of things that fall under this category, so I leave the thread open ended so we can all add in things that might need to be taken into account.

Here is the lowdown -- I will build at the very least a 180 degree circular projection setup based on whatever we come up with here using EyeFinity. I'll take the risks associated with the build, but I want us to debate out the whole thing so I don't miss something super-critical in the process. The focus need to be most cost effective way possible and this will be specifically designed for my F-84F simpit. Keep in mind that I already own a copy of Sol7 Simpit Edition for the circular pre-warp correction.

Fatmotti · Post by **Fatmotti** » 13 Sep 2009, 08:32

Unless you are talking about 2 or 3 years out, LED projectors just aren't there yet, in an affordable price range.(3x1080p LED will run you 20k) The el cheapo LED proj are going to be way too dim and at max 800x600.
Also the only decent short throw projectors I've seen are all 2k+ in price and are 1024x768 (and not LED).

I've thought about this a lot too. Some random thoughts.

Sol7 software definitely seems the way to go just for the edge blending even if you don't curve the screens.

How big is your room? Have you thought about rear projection?

How tall of an image are you wanting to create? Everything flows from this starting point IMO.

Are you a better carpenter or welder? I'm assuming you plan on doing all the work yourself?

I originally started looking into this by wondering if it was possible to build a better version of the NEC curved monitor using projectors and a TH2go.

I found this stuff, that might be interesting to consider if you can do rear projection.
http://solutions.3m.com/wps/portal/3M/en_US/Vikuiti1/BrandProducts/secondary/vikuititutorials/rearprojectionscreens/
http://www.provantage.com/3m-98-0440-4426-5~73MCO0CA.htm
http://www.youtube.com/watch?v=mJCLA1HUwmo

Matching this stuff with a custom curved glass window might make the ultimate screen. And I think you could do a 117.69" X 22.04" screen (glass+film) for less than 2k. Not saying this is the size to go with, just an initial estimate. 3X 16:9 can get real wide real fast when you are talking projectors.

Post by **BHawthorne** » 13 Sep 2009, 09:40

I went digging around the Projector Central website at specs. The goal I'm shooting for was initially a projection height of 96" but when I did some figuring it made more sense to drop down to 84" projection height. Figuring a standard wall as 8' tall, that'll leave 6" less screen on top and bottom that I can blackout the wall as needed.

5'7" throw for 84" projection height seems pretty ideal. It looks to be 2500 ANSI Lumens, 1024x768 native. I'm not too hot about the resolution, but the throw, lumens and price are right. The only one I could find that was short throw and not insanely priced was this:

I'm in agreement about the LED projectors. I dug all around the specs on that site and nothing was remotely in my spec needs relating to LED. The tech just simply isn't there yet.

Fatmotti · Post by **Fatmotti** » 13 Sep 2009, 09:51

Cheapest way I can think of to do this for front projection would be to get two 240" pipes bent in a semi circle for the top and bottom and two 46" pipes for the left and right. Make a frame out of these and then stretch blackout cloth across the frame. 240x46 is the equivalent of three 92" 16x9 screens. Is 4 feet from the ceiling to the top of your cockpit enough screen?

How far away from the screen will your head position be? I guess that's a big factor too, along with getting in the way of the projector images. Another reason to go rear projection maybe? Seems like you can sit much closer with a RP setup and therefore have a smaller screen perhaps?

This guy sells 9x22 feet of blackout cloth for 100 bucks.
https://www.carlofet.com/store/index.php?main_page=index&cPath=1_10

Fatmotti · Post by **Fatmotti** » 13 Sep 2009, 10:03

Well modify that to a 336" pipe. (i have no idea if that even exists)

Won't a 140" 4:3 1024x768 screen be really pixely? I imagine you'd have to sit 20 feet away from the screen to not see a big blocky image?

1080p is a 1:1 viewing distance, what's 1024x768?

Post by **BHawthorne** » 13 Sep 2009, 10:07

Hrrrm, I would find a projector noone seems to sell...hrrrm.

Looks like Optoma EX525ST and Sanyo PDG-DXL100 both spec out like the Acer, just $200 more. Maybe I'll have more luck searching for those.

http://www.optomausa.com/product_detail.asp?product_id=394&itemno=EPEX525ST
http://us.sanyo.com/Projectors-Products-by-Category-Ultra-Short-Throw/PDG-DXL100

Fatmotti · Post by **Fatmotti** » 13 Sep 2009, 10:30

84" tall is gonna make it really big if you go 16x9 (of which I don't think there is a short throw anyway so it's a moot point)

are you not worried about a combo of 140 inches and 1024x768 being too big and too low of a res? How far do you sit from your 720p projectors and hows the pixel density on that? I'm guessing you want to do x3 projectors at that size? You'd need a lot of space to do 5.

Now that I think about it, how screwy would the FOV be if you went past 180°? I'd think you'd need the game engine to render screens 4 and 5 differently rather than just the normal "bending" that happens with the 3 screen angled setup. Wonder if you can map the look left look right to screens 4 and 5? (I'm not much of a sim player) But i can see 5x1 setups being screwy in FPS style games now. hmmm

Post by **BHawthorne** » 13 Sep 2009, 10:36

This guy sells 9x22 feet of blackout cloth for 100 bucks.
https://www.carlofet.com/store/index.php?main_page=index&cPath=1_10

I'm taking bets if I emailed him he'd sell it to me by the yard or foot. The guy on ebay that sells like that previously said to just email him the requested length for custom price quote.

Won't a 140" 4:3 1024x768 screen be really pixely? I imagine you'd have to sit 20 feet away from the screen to not see a big blocky image?

1080p is a 1:1 viewing distance, what's 1024x768?

I dumped the numbers in at Projector Central for my SP5000 and came up with some figures. I've previously ran a SP5000 720p at 14'4" throw in my computer/media room. That looks to be around 58" tall for 720p and that wasn't too bad at about 10' viewing distance. The screen-door was there but it was bearable. It'll probably start getting boarderline quality issue going taller. I need to make some decisions as to what uniform screen height would be a good compromise. In the previous message I was thinking 7' tall screen, but even going down to 6' tall with a foot of dead-space above and below the screen would probably not effect the immersion factor much. With these being 4:3 projectors the smaller height also means smaller width coverage. That starts eating into the FOV capability of the design.

The simple fact about this so far is there will have to be some compromises made. There is no such thing as an affordable 1080p short-throw projector. As is, I'm humoring the eventual purchase of up to 6 $900 projectors in this thread currently. That price is a bit of a gut check. It might pay off better for me to go digging for a source for those cheaper Acer S1200.

Now that I know what sort of projector throws are possible I guess I should start CAD drawing up some layouts to see what it can and can't do.

Post by **BHawthorne** » 13 Sep 2009, 12:09

I whipped up some CAD layouts of the setup. I can go 5 foot high on the screens and allow for decent projection overlap between the projectors to be blended in with Sol7. That leaves a 1.5 foot of dead area above and below the screen.

I need to design a modular screen that I can put together and break down that will fit a 10x10' footprint and also have the mounting hardware for the projectors overhead. You mentioned using piping. That seems like it should work. Some sort of extrusion or piping would be easy to shape with a pipe bender.

My simulator is much larger than this, but I can work out all the bugs at my leisure with this size of a screen prototype. I also wish projectors could be used in portrait mode. This would make the screen design easier to accommodate the projections at full height but the cooling on projectors prevent using them that way.

Initially, I'll target 3 projectors for 180. If that works good with the design I'll later add in the rest of the projectors as I can afford them. With this layout it makes more sense to stop at 5 projectors and not worry about the 6th.

Now that I think about it, how screwy would the FOV be if you went past 180°? I'd think you'd need the game engine to render screens 4 and 5 differently rather than just the normal "bending" that happens with the 3 screen angled setup. Wonder if you can map the look left look right to screens 4 and 5? (I'm not much of a sim player) But i can see 5x1 setups being screwy in FPS style games now. hmmm

I'll use this almost exclusively with flight simulator games, so that shouldn't be too much of an issue. Most flight simulators are good about custom cameras. I've also seen people using FPS games with panoramic screen setups too. There are a few example videos on YouTube.

cybereality · Post by **cybereality** » 13 Sep 2009, 18:56

This sounds really cool. After I saw Gamer I really wanted a setup like this (the kid had a full 360 degree holographic display he would sit inside, very nice).

Check out what these guys did, very cool stuff:
http://www.youtube.com/watch?v=Cqh_F4iN8pg

Post by **BHawthorne** » 14 Sep 2009, 03:30

Seems to me the greatest stumbling block for builds like this so far is projector base cost. Looks like the short-throw lens technology is there with decent lumens ratings, but I'd prefer seeing $599 projectors not $999.

About the screen design...
I'm uncertain yet on the tactic I should use as far as screen shape. The polygon design like above has advantages as far as focusing. A true circular screen would feel a lot more seamless but you're fighting lens focus issues in areas on the screen. I'm a bit neutral about the issue at the moment and probably need some debate about it more before I settle on the screen geometry. Sol7 can pre-warp and edge blend just fine for both examples.

Optoma EX525ST vs. Sanyo PDG-DXL100...
Looking over the user manuals for both it looks like they share some of the same components...namely the same lens and focus ring and the same remote? That makes me think the same OEM is manufacturing these 2 different projectors and selling them under these two different brands. The odd thing is the interface panel and the back connector configurations are different. One has HDMI while the other is DVI-I.

JKeefe · Post by **JKeefe** » 16 Sep 2009, 20:25

Project cost and required space aside, I think you may have a problem throwing 180-degree or larger fields of view at sims. Most rendering engines aren't set up to provide this much view all at once (although you can turn your virtual head), and thus sims may choke in this situation.

What title(s) do you plan on using?

Post by **BHawthorne** » 17 Sep 2009, 04:47

Project cost and required space aside, I think you may have a problem throwing 180-degree or larger fields of view at sims. Most rendering engines aren't set up to provide this much view all at once (although you can turn your virtual head), and thus sims may choke in this situation.

What title(s) do you plan on using?

I'm coming at this a bit backwards. I am starting with a 20 foot long section of real F-84F and working the project from there. As an F-84F isn't exactly an aircraft that people fly much in flight sims I'll probably have to implement my own F-84F add-on with whatever I use. Sure, Alphasim has an old F-84F freeware, but the instrument planel layout is different than my aircraft and a few other issues are there too.

Undecided at this point. It's too early in my simpit design to definitively say. Possibly DCS: A-10, FighterOps and FSX. Most of the build cost on this is projector cost. That's why I'm selling my 3 current projectors and getting 3 new short-throw ones. As is, I could do a triple-projector setup right now, but I want to eventually do 5 projector and not have to use an ungodly large room for it. Throw distance is playing a major role in this design so far. I might just go 5870 but then do the projection by designating the front screens as an SLS single area but projector 4 and 5 as independent projector cameras in-game. I am aware of 3d engines simply messing up over 180 degrees and I'll have to account for that also.

Cynagen · Post by **Cynagen** » 17 Sep 2009, 11:29

I'm going to throw in a projector suggestion for this thread, the one in my signature. The Sharp XR-10X. It's specialty is short throw.

DLP, 2000 Lumens (1750 on Eco-Mode plenty bright with a room @ 15% on a screen that's ~0.8 reflectivity), 3000 hours per bulb, $500 refurb, less used.

I've gotten great results, no visible screen door effect at any throw distance I tried on it, and it says the throw is 5 and a half feet minimum, but I tried it shorter without a problem. The 1.15:1 lens zoom helps fill in space that you need to fill in without making the image distorted or crappy. The projector includes 16:9 display mode for 720p and 1080i, it just letter-boxes the image, but with it being DLP, there's less than 5% light being reflected in those spaces, so you won't even notice them at all.

Post by **BHawthorne** » 17 Sep 2009, 12:12

I'm going to throw in a projector suggestion for this thread, the one in my signature. The Sharp XR-10X. It's specialty is short throw.

DLP, 2000 Lumens (1750 on Eco-Mode plenty bright with a room @ 15% on a screen that's ~0.8 reflectivity), 3000 hours per bulb, $500 refurb, less used.

The price is right, but the lens is the deal breaker on that one. Doing an 8 foot high screen would take 19 foot 7 inches with the Sharp XR-10X, while the Optoma EX525ST has a throw of only 6 foot 5 inches. Really, looking strictly at the specs, the Optoma EX525ST, Acer S1200 and Sanyo PDG-DXL100 are the only projectors sub-$1000 with the ideal lens throw. Of that, only the Optoma EX525ST is readily available in the US. I'm really stuck as far as projectors with the Optoma's spec and price range. I'd love to find a few used EX525ST, but they've not been out long enough to see any used on ebay yet.

cybereality · Post by **cybereality** » 18 Sep 2009, 07:14

Well if you want to talk about short throw distance look at the SHOWWX LaserPico projector (only 6", yes inches!):
http://www.microvision.com/showwx/specs.html

Resolution is low, but its laser so it can go on angled surfaces without focus issues. Its also only going to be around $400-500 so getting like 4 or more of these for HD resolutions could be economical.

Post by **BHawthorne** » 18 Sep 2009, 07:17

10 Lunens at 848 x 480 for an 8 foot tall height of screen isn't gonna cut it. The projector needs 2000+ Lumens not 10. Also need at the very least 1024x768 resolution -- frankly I'd prefer 1280x1024 native or better. The second or third generation of that might be very promising though as laser isn't going to need lens throw.

To pull what I have in mind off is simply difficult to achieve. The technology is borderline not there yet. We're looking at the first generation in much of this technology.

In an ideal world we'd have 3000 lumen 1080p projectors with 45,000 hour LED bulb life that short-throw 96" tall at 5 foot lens throw for sub-$1000. I suppose that might occur in a decade from now, but I'm purely dreaming at the moment with that spec requirement.

Post by **Mach1.9pants** » 18 Sep 2009, 08:21

Can you remember to PM me when you find that projector? ;)

Post by **BHawthorne** » 18 Sep 2009, 09:12

Can you remember to PM me when you find that projector? ;)

hehe, will do...but don't hold your breath, :lol:

Tentatively, I'll have some data on the Optoma projector and the 5870 "Six" card in about the next month. I figure it would be best for me to buy only 1 of the projectors initially and prototype a single section of the screen as to validate this is all plausible. That way I'm not knee deep in purchase regret if the specs are in error. I'm mostly curious to see how 1024x768 DLP looks at 8 foot tall. I'm used to LCD projector at 5-1/2 foot tall projection. LCD shows the screen-door effect, while I'm not sure how DLP handles the pixels yet. My only consistent projector experience is with the InFocus SP5000's I've owned for few years now.

Post by **BHawthorne** » 22 Sep 2009, 15:00

Durring my daily digging around I ran into a Paul Bourke projection webpage that is directly applicable to this situation.

http://local.wasp.uwa.edu.au/~pbourke/miscellaneous/cylmapper/

I have access to a mac, so this would be ideal for me to do the screen and projection layout design on. Just hope I can get a copy of the app. In the examples in that webpage he's using only 5 projectors to achieve 360 degree coverage, so EyeFinity should work ideal for this.

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