Tryin a half dome

[VRgamesterz]

Have you guys checked out GeoDome, I'd like to try a half dome using those safety mirrors that someone posted about before. My question is, would this cause to much distortion on the dome because no software is used to warp the image or give it a bugeye effect? If I place the projector infront of the mirror and have it reflect the image onto a half dome would it be playable? I'd really hate to spend the cash on the dome, the mirror won't break me and I have the projectors. I've read up on some of Paul Bourke papers, so im guessing the big problem is warping the image to the dome so it looks correct? I found a good pop up dome, not cheap but should work, also can make it into a half dome which im I'd like to work on. I also bought mylar mirror sheets, maybe I could use that and make my own shaped spherical mirror. Why does everything have to be so damn $$$$ to have a good experience..

Ku

[Okta]

I would love to try that out... one day. I think it will be workable depending on what you need out of it. So long as you set it up so the image is centred correctly there shoudl be little distortion around the centre, obviously the stretching will increase towards the periphery. In some game you will be able to alter the hud with cvar/ commands and such to bring your info to the centre, also in games like Oblivion you can do this and increase the FOV.

This is how the JDome works and i think it would be great!

[cybereality]

I don't know much on the topic but it would be great if you could get that to work.

[cadcoke4]

I just visited the GeoDome web site, and it is pretty sparse regarding any descriptions of the dome itself. I can't see how a quarter sphere can be inflatable and provide a curved inside surface. Yes, they could have inflated just a perimeter, but the "dome" would just be a one-curve surface, like the surface of a cardboard paper towel roll.

As for the idea of using safety mirrors... I can see how it would spread an image out wider. But this that wouldn't change the focus of a projected image that was originally made to be focused onto a flat surface. I would think only one depth of the sphere would be in focus and the rest progressively out of focus. But, I just did a bit of internet research, and came across this quote "In my experience about 50% of commodity projectors will meet the focus requirement." This is from a document that has A LOT of detailed information about planetarium projection off of a mirror.
http://local.wasp.uwa.edu.au/~pbourke/m ... r/faq.html" onclick="window.open(this.href);return false;
I hate it when a URL won't display fully... here is another attempt to force it to
http:// local.wasp.uwa.edu.au/~pbourke/miscellaneous/domemirror/faq.html

By the way, I have created patterns for a couple of inflatable items, so I know how to develop patterns for stuff like this. If someone knows how to set up a projector for it, and wants to sew a dome, I would be happy to create an open-source pattern.

Joe Dunfee

[VRgamesterz]

Yeah I've read up on some of paul's pages. Im gonna give this a shot, if the picture is alittle distorted I might be fine with it seeing I should be focusing on the center when playing FPS, I just want to feel surrounded and having a picture that is some what rapped half around you might just do that, give you that feeling.. Anyways for the guys who made a post in the DIY section, check this site out on dome tents http://www.shelter-systems.com" onclick="window.open(this.href);return false;
Im looking into having them make a custom dome size for me, they have a 14ft diameter one which is to wide, im looking for an 8ft wide and 7ft height, waiting to see if that can be done. they also sell grips/clips so if someone wanted to make thier own using a tarp and some pvc pipe they could indulge. Joe, if your talking about making some kind of software that can warp the computer game image to fit the dome, then PLEASE ring my door bell!! But if I read correctly from what paul was saying, then the distortion of the image should be all that bad with the more powerfull graphic cards but like I said I could of been confusing myself. But im gonna try this setup, I have the projectors and the room and mylar film, or I might just by the mirror that Paul said to get. Either way this is gonna get done.. I just hope it's somewhat COOL!!

Ltr

Ku

[cadcoke4]

Ku, to be clear, I was offering to design the FABRIC part, not the software part.

Thanks for the link to the Geodesic shelters. I wonder if you can add a fan to inflate them and produce a smoother surface. However, I suspect the seams are sewn straight, and not curved as they would be for a true sphere. If they were inflated, the corners would tend to wrinkle. Ku, if you are asking them for a custom size, why not ask for a true spherical shape? They may already have the pattern, and you are going to pay for custom cutting of the pattern anyway. The price may not be any different.

For the dome shelters, I imagine that having the structure is an advantage, even if you inflate, because then it doesn't collapse when the fan is off.

I continued to look into Paul's web site, and see that other geometries are possible. He didn't mention a cylindrical surface, but that would be a lot easier than a sphere to fabricate. You would just hang a cloth like you would a curtain. To form the curve, you could get a length of PVC pipe, and simply run a string from one end to the other, like a bow-and-arrow. It could be hung from the ceiling, or if you can make it free-standing by using 3 microphone boom stands (about $15 each). I know about this because I am a puppeteer, and have imagined how I wanted to make a puppet-stage scale theatrical cyclorama. A source for a large seamless cloth can simply be a queen or king size bed sheet. The hem is already there! You will need to steam it while hung, or iron out the wrinkles. Also, wide theatrical cloth is not very expensive, and you can have them cut it to your size and hem it See Rosebrand.com for their 10ft wide "Poly Cyc" fabric at $14.50 a yard. So, for a 10ft wide x 8ft tall piece, it is $39. If they sew it, the price will probably be over $200, but again, sewing a hem is not difficult and you can purchase a used sewing machine for around $20.

For the curved mirror, you might just bend a plastic mirror. Perhaps a polished stainless steel sheet would be viable as well. The "mirror like" stainless steel sheet, .06" thick and 12"x12" is $18 at http://www.mcmaster.com" onclick="window.open(this.href);return false;

Alternatively, you may be able to get away with using a short-throw projector. If you want to project from the floor, you could just reflect that off of a flat mirror to keep the seating area clear. A flat front surface mirror wouldn't cost much. You can even make your own by removing the back coating on a cheap $1 mirror.

Please note, that while I am talking a lot, I don't have a projector to try any of this out.

Joe Dunfee

[VRgamesterz]

Geeeezus crykee, this would work perfect!!! Only one problem, one BIG problem.
http://www.floridamusicco.com/proddetai ... sol7si.htm

Why so damn much? is there any software that can warp the image at no cost.. Crazy! It's like im starting all over again trying to find or wait for a decent HMD that is never gonna happen in my life time, there is always a bridge blocking us, either a $$$$ bridge or one that is not finished to cross yet.

You know it's funny that you have these companies that are selling their product like JDome, have you seen those videos! very distorted. the only creativity was the frame and the fabric used. TOOB, why so much?? $3k for a inflatable half dome, no projector, the image is still distorted. Time for us to WIP something together fellas, I got decent projectors and Mylar mirror film, now its time to build and shape.

Joe thanks for some of the inputs and idea's, hopefully we get some more. I wouldn't mind being a member of the planetarium, however it's spelled but how many in there aren't doing this for gaming. None for that matter.

BBL

Ku

[cadcoke4]

For cylindrical projection, I think the only distortion that will be absolutely needed is to compress it horizontally. Perhaps this can be accomplished by somehow forcing the video card driver into thinking the display has a different aspect ratio. I know we would do that back in the early days of AutoCAD. Note that this is not by changing the resolution of the image, just making it think the pixels are not square. I don't know if this is as easy to do now that displays communicate with the video driver directly and that most displays have a square pixel aspect ration.

I know this will not be a perfect, non distorted image, but it should be pretty close. To be completely correct, the image has to be distorted by a slight rainbow type shape. I am starting to suspect that there is a way to send a command to the video card to tell it to do this for us. But, I just don't have enough understanding of video cards to say this is true. Perhaps the OpenGL people will know.

As for the projection screen. I just looked at the sizes for king size bed sheets. It looks like they are big enough to be used, 108 x 102 inches. It even has a handy pipe hem along the 108" side!

Joe Dunfee

[cadcoke4]

Ku, I am not clear if you are building a sphere or a cylindrical screen. Which is it?

Joe Dunfee

[VRgamesterz]

I like the half dome setup, I think its an easy setup getting a big picture. The cylindrical screen, im not even sure what that looks like. Now I just found a VRGL 1.5 program from http://publicvr.org/html/pro_vrgl.html
I wounder if there is any programming that I'd have to do, if thats the case then im not gonna even try it. Joe I think using a bed sheet would allow to many wrinkles, soft spots because of how thin the fabric is. I just bought a 7ft x 9ft white screen fabric off ebay. He sells them bigger if needed, maybe I could use the grip/clips and support it that way to the pipes. But for your Ideas that you've givin me, I can't go wrong tryin, atleast its a cheap way if it doesn't work.

Ku

[VRgamesterz]

I guess I will be trying to make my own spherical mirror shape of some sort, or see if this cheap one I just bought off ebay will work for testing, maybe with some work I can fit the mylar film over it if needed but im sure that would be a pain. Those First surface mirrors that Paul Bourke recommends from AUSSIE are way to much for my pockets.. Plus add the shipping and your talking $1,000. Naaaaaaa

I still haven't heard from shelter-systems about my custom half dome. Once my screen comes in and the mirror im gonna get started on forming a frame. This should be a good spring project...

Ku

[cadcoke4]

Ku, regarding wrinkles, there are ways of dealing with this that are used for theatrical backdrops. For curtains, often a weight or weighted chain is put in the bottom hem. You can purchase this stuff at a good fabric store. If the edges are given a slight tug, that will also encourage it to hang straight. But, not too much of a tug, or the curve will distort.

However, in this case, I think an iron would be sufficient to deal with the wrinkles. At least give that a try, and just add more stuff if you think it is necessary for a good hang.

I have attached a rendered image showing a very simple set-up of a projector pointed at a cylindrical mirror and reflected onto the cylindrical screen. In this case, I was showing a king-sized bed sheet hung from a curved pipe.

Joe Dunfee

[Raptor007]

This thread might also answer some questions.
http://www.mtbs3d.com/phpBB/viewtopic.php?f=26&t=3690

A couple tips:
-It was much harder then i thought to make a curved mirror. Most of the flexible mirror surfaces will not reflect an image at all. Just muddy light. A pure mirror is your best bet.
-If going for a front projection (like the attached picture). In general the throw is too short and such a large vertical keystone is needed it will be hard to find a projector that will work.
-Rear projection can work but of coarse you need a mirror that is concave. You can bend a cheap mirror from bed bath and beyond enough before it breaks (don't ask how i learned that one...)
-Now a curved screen is hard enough, for a dome large enough to cover some peripheral vision, it might be best just to not reflect the image at all and use rear projection.


I don't have this setup with a projector yet, waiting on some HDMI 1.4 projectors in summer, but it worked from some flashlight and laser pointer tests.

[VRgamesterz]

Cadcoke4, good picture.. Thats pretty much what im gonna try first. I just received my cheap safety mirror and I plan on trying to fit the mylar mirror film over it. My screen is 9ft wide by 7ft height. What im using to curve the screen is aluminum 1/8 x 1 1/2 8ft, it bends very nice. I'll show some pictures once done. Im going to play with the VRGL and use UT2K4 for now, planetJeff and those guys used the VRGL 1.5 for dome use. Here is another page I read on about doing this. Maybe you have read it too!
http://planetjeff.net/IndexDownloads/Henden2008.pdf" onclick="window.open(this.href);return false;

What I like is that they didn't just try a dome, Im going to use these clips with a bungee cord to make the screen nice and tight once it is in a curved shape, I was thinking of using velcro using 3m adhesive which would be used to put the velcro on the screen but I think the clips will works fine and allow for me to take it down quick when needed. If it works and gives a good immersive feeling, COOL! If not then, NEXT PROJECT!

Raptor, I don't think it will be to hard to do but time will tell. I don't know what you were using to flex the mirror but I bought the cheap one off ebay for $29, its not first surface but it also doesn't cost $550 not including shipping. getting the mylar to cover the main area shouldn't be that hard, I will try working on that within the next few days..


Ku

[The_Nephilim]

Geeeezus crykee, this would work perfect!!! Only one problem, one BIG problem.
http://www.floridamusicco.com/proddetai" onclick="window.open(this.href);return false; ... sol7si.htm

Why so damn much? is there any software that can warp the image at no cost.. Crazy! It's like im starting all over again trying to find or wait for a decent HMD that is never gonna happen in my life time, there is always a bridge blocking us, either a $$$$ bridge or one that is not finished to cross yet.

You know it's funny that you have these companies that are selling their product like JDome, have you seen those videos! very distorted. the only creativity was the frame and the fabric used. TOOB, why so much?? $3k for a inflatable half dome, no projector, the image is still distorted. Time for us to WIP something together fellas, I got decent projectors and Mylar mirror film, now its time to build and shape.

Joe thanks for some of the inputs and idea's, hopefully we get some more. I wouldn't mind being a member of the planetarium, however it's spelled but how many in there aren't doing this for gaming. None for that matter.

BBL

Ku

Hi Yes sol7 is the Professional version. they are going to be making anew program called NTHUSIM..
http://nthusim.com/" onclick="window.open(this.href);return false;

The Professinal version of NTHUSIM which does 3 Projectores cost 400. the other one that they offer does one Projector, should be around $200 or so bucks USD.. It also allows you to do 3D if you use that technology

[cadcoke4]

VRgamesterz, I just did a bit of shopping around for projectors, to see what prices were vs. throw ratios. There are a lot of short-throw projectors out now for under $1000. The Dell S300 is around $700, and offers WXGA (1280x800) at a .5:1 throw ratio (i.e. the width of the image is 2x the distance of the projector from the screen).

I was also surprised to see how many XGA projectors are in the $450 range. At that pricing, it becomes viable to use multiple projectors. I wonder if multiple video cards synchronize their refresh rate, and the DLP projectors their color wheel, so that all of the images can be stereoscopic at once?

By the way, NO shopping source I could find will provide the black levels.

Joe Dunfee

[cadcoke4]

I have a concept in mind for a vacuum dome. This way, the dome can be in front of you, instead of something like an igloo you must get inside of. The idea is to form a structure from pipe, and then cover with the cloth. A small fan draws the air out, forcing the cloth to be drawn inward.

The dome portion of the cloth would still need to be sewn with seams like a beach ball. The planetarium people have commented how immersive it becomes when no seams are visible. Aside from vacuum forming plastic sheet, I wouldn't know how to do a seamless structure like that.


Joe Dunfee

[VRgamesterz]

Well this should help with gaming on a curved screen... price isn't to bad for what can be done and not having to use a spherical mirror.. http//nthusim.com Finally released a home version software for single projector or 3 when using triplehead2go or Eyefinity... Im gonna dab at the single for now, the demo last only 10 minutes but can be restarted again and again. I received my saftey half dome mirror, didn't try the mylar film but I would have to if I was gonna stick with this. Figure comparing the spherical first surface mirror at $560 without shipping and then doing your alignments, this software just killed that idea!!! Awesome...


Ku

[cadcoke4]

VRGamesterz, I just tried the http//nthusim.com link, but it just automatically forwards me to a wikipedia article on html.

Joe Dunfee

[andyb]

Hi Joe,

Try http://nthusim.com/" onclick="window.open(this.href);return false;

[VRgamesterz]

Yup I forgot the DOTS lol... Still in testing, pretty much Im not to happy with these projectors I have so Im trying to find a Dell S300 or a BenQ MP772 ST bot have great short throw lens. The projector I have sucks.. 1.92 throw compaired to .52 and .61

Ltr..

Ku

[zazoo]

Hi VRgamesterz,

I don't know how far along you are in your project, but I thought I would give you some links to possible DIY dome solutions.

The first is Global Plastics, they make acrylic and Lexan domes to order, but they seem to be limited to a 60" dome size with the correct 30" height radius (they have a 69" size, but it does not have the correct radius, I think the acrylic dome dimensions begin to distort once the dome size gets past a certain point--if you go for acrylic, you may want to order the thickest version possible): http://www.globalplastics.ca/domes.htm

If you go to their gallery (far right column, about halfway down), you will see photo with a set of domes labeled "Projection Domes"; which appear to have a frosted surface (I am not sure if they are for rear or front projection): http://www.globalplastics.ca/2480.jpg

The second manufacturer is Fiberglass Specialties. They have a dome section and can build very large domes to order (from 6 to 12 feet single-piece). Obviously, these would be used for front projection setups (as long as the interior of the dome is smooth, which they do not picture--hopefully there are no cross-braces or beams designed into the inner surface of the dome): http://www.fiberglassspecialties.com/domesindex.asp

These fiberglass domes look similar to what the TOOB dome projection system is using. I had a previous link about the TOOB system a few months ago ( http://www.mtbs3d.com/phpbb/viewtopic.php?f=3&t=4494 ); since then, it looks like they added some new models, and they are now marketing them with suggested stereo3D projectors. However, note that many of the "TOOB-recommended projectors" are not on nVidia's 3D-Vision certified projector list (assuming you are going to use it with 3D Vision): http://thinkoutofbox.com/id75.html

P.S. I have no idea if any of these domes would work for a DIY solution, but it may be worth some investigation. Hope it helps. Please post again to report your findings! Good luck!

zazoo

EDIT: The nVidia 3D Vision + TOOB comments are there for anyone considering that hardware combination (VR, I see that you are an AMD guy , so no worries).

[VRgamesterz]

Zazooooo, thanks for the info!! Trying a half dome is no picnic. I finally got a nice short throw PJ, .51 ratio. I've changed gears alittle and decided to make a curved screen instead.
It's 4.7ft height by 16 width. Also made a swivel chair with the projector mounted to it so when your sitting and using a VR gun, turning also makes the image turn on the screen. The hard part is trying to align the image even when using the Nthusim software. Im just having issue getting D3D games to load up, openGL games are working fine. I took some pic's and will post some up just to show the idea.

I do still want to dome something!!
I just sent an e-mail to globaldome on the projection dome pic they have. Im hoping that is for rear projection, that is the only way I'll try it.

Ku

[cadcoke5]

VRgamesterz said;

Also made a swivel chair with the projector mounted to it so when your sitting and using a VR gun, turning also makes the image turn on the screen.

Wow, that sounds very interesting. Are you saying the projector is inside the seat you are sitting on? How does the computer know the aim of the projector has changed?

Joe Dunfee

p.s. I changed username from cadcoke4 to cadcoke5, for some reason I couldn't log in under the old one.

[tritosine5G]

Hi,
Kodak's discontinued screen ektalite has similar shape:
http://tinyurl.com/38vr9yp
and gives gain compared to mattewhite like 10+x vs 1. I would need that kind of brightness for shutters , and brightness is never enough. If theres no hotspotting , Ican use it to have better contrast (diy iris).

http://archive.avsforum.com/avs-vb/show ... genumber=3
-hotspotting would be no issue to me (gaming).

What do you think how I can get a similar shape to the ektalite, and can I hope for irreally huge screen gain numbers, once its sprayed with a gain of 4 3d HD paint?

[tritosine5G]

http://forum.dvdtalk.com/dvd-home-theat ... light.html

[Likay]

I dared to take a screenshot with a 500-watt worklight pointed right at the screen from the side.

Just: Incredible!

[VRgamesterz]

Well this is what I've done so far. Im not having a good time getting the Nthusim software to work will all the games, maybe something with my 2 systems, not sure..

projector-project 003.jpg

First picture is the frame. And so on with the screen and the test image. Also what the projector and chair look like.

projector-project 003.jpg

projector-project 014.jpg

projector-project 019.jpg

projector-project 016.jpg

To sum things up, the image isn't perfect when moving side to side, I all ways have one edge that is to low, Im sure this could be fixed if the curved screen was shaped perfectly but im not gonna bother. But once you decide to move the curser for aiming and move the chair in that direction, that effect is pretty cool. Thats where the immersion kicks in BUT for only 10 minutes LOL, then the software demo runs out..

Only SOF2 worked and old Quake, wierd only the OpenGL games. Also your sitting only 5 feet from the screen and your head doesn't block the image.

[Likay]

Nice piece of work!!
I haven't really had interest in curved screen until now but it may have changed.

[cadcoke5]

Sorry VRgamesterz, but I still am not sure I understand your set up.

In picture 014, I see your projector hanging from your structural pipe frame. Towards the bottom, towards the floor there is the black seat on the frame. Perhaps the entire frame, with both chair and projector, swivel as a unit. The swivel point being perhaps behind the seat, and not in the center of the seat. I guess an alternative approach might for the seat to swivel around its center, but for a belt around a pulley to translate that movement to a shaft with another pulley to a belt that swivels the projector around its center.

What is your approach?

It's OK if you don't want to go into much detail, but I am sure you will find many people very interested in your work. It seems to be both simple and effective in terms of the hardware. How many degrees in the field of view without swiveling? How much can you swivel?

Most importantly, how does the computer know you are swiveling so it can update the projected image?

Joe Dunfee

[VRgamesterz]

Well if you look at pic 14 and see the pipes, not the end pipes, this is where the screen reaches without moving it. So thats a pretty good size, now the computer doesn't need to know, it's more per your movement when aiming.

Figure looking at your monitor and you aim to move your screen but the monitor sits still. When you aim the gun left or right, you don't have to move the gun if you use your feet to turn your chair. I was trying to get the sense of it being like a camera view following my movement. So the PC doesn't counter for anything for that, your just moving the PJ, something the VR gun guy wanted to do with the pico PJ in a gun.

Really I think the degree is only like 45 to each side when moving, the only prob is the screen edges won't be perfect because of the distance to the screen when turning.

I would love to sit and come up with some kind of design for a complete chair, and to make the screen tigher so there is no waves in it. Really the Nthusim made this work, if not for that then the image would be to distorted. Overall it was fun to do, but a pain to setup and tear down and setup etc...

Ku

[mayaman]

I ordered my TOOB 4 foot dome today. I will give a review when I get it.

[lnrrgb]

Saw this over @ Anandtech - did not see any $$$ values over at their website, but I'm guessing its spendy.


Oops.... a resurrection.... three years dead, my bad