Re: Creating a planetarium using Ruby

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First, thanks to everyone for the suggestions and links.

Unger and Jean:

For the moment I have not a webpage because until now, I am looking
for funds fo start the project on the Instituto Polit'ecnico Nacional
(www.ipn.mx) because I can't to cover the cost of the hardware (I'm
estimating about from USD 10,000 to 50,000 to buy some dozens of
decent video cards and monitors in the first stage of the project).
There are many issues to solve:

1. This solution has to flexible, in terms of be able to be used on
different planetariums.
2. In the first step, it must to be capable to project some stuff
using a 3d stellar system (like starplot or something)
3. After, it has to be connected to a telescope and to project the
received movie conveniently.
4. To be a standard movies projector to show some stellar-educational movie=
s.

Actually the cost of a planetarium projector machine is on the order
of about USD 150,000 (but it does include also multimedia movies, a
stellar database and stuff like that). In any case, I think that a
open solution may reduce the total cost of building and mantaining a
planetarium.

This project may to grow too much (for example the using of internet2
to connect the video output to telescopes from another point of the
world, etc) but for the moment I think it would be nice to keep the
perspectives low. I am also starting contacts with the "Luis Enrique
Erro" planetarum, at http://www.planetario.ipn.mx/ and they may be
happy to work in this project also.

As, effectively, you suggest, for the moment we have not much
information about the final hardware requirements, for example, the
total resolution of the image, the   possible surface area of the
sphere (usually the planetarium's vaults are not perfect spheres), or
issues like: how to solve the overlap of the projectors on the vault?

The current machine on the "Luis Enrique Erro" planetarium is a Zeiss
IV with 150 projectors.

On 3/13/06, Unger Richard <ric...@te...> wrote:
> Hi!
>
> Wow! Now that sounds like a really cool project!
>
> I don't think Ruby will necessarily help you here... Ruby is needed when =
you want to enable parallel, independant use of screens, specifically for m=
ultiple independent consoles.
>
> What you want is more of a giant "Xinerama" setup. However, IMHO Xinerama=
 may also not be the way to go - it might be quite some work to recode that=
 layer.
>
> Also, 20-30 Video-cards is a lot (last time I checked, I could put at mos=
t 6 in my Workstation ;) )... May I ask if you have already solved the prob=
lem of the hardware you will use?
>
> If not, I think this will be the major area of work. I am not aware of an=
y PC Hardware capable of driving 20 Graphics cards. If if you were able to =
hook up a PCI bus with 20 cards you would never be able to drive them in sy=
nc - the bus won't support that kind of volume of data. With PCIe you're ge=
tting closer. For example, Matrox is making 1-Lane PCIe GFX Cards, and mode=
rn PC Hardware often has 20 or more PCIe lanes. Whether the processor and b=
ridge chips will manage to drive 20 cards sounds doubtful.
>
> More likely you will have to use several PCs in parallel, with each PC co=
ntaining several graphics cards. In this case you will need a software laye=
r to distribute the graphics processing over multiple nodes in a network. T=
here are existing software packages to do this. If you use OpenGL, the Chro=
mium project is one such software layer for OpenGL. (I saw an article recen=
tly where someone ran Quake3 on 24 screens at a resolution of 10240x3072px =
using Chromium).
> Using OpenGL may be a good choice in any case, as I think you could more =
easily implement the distortion needed for your non-flat projection in the =
OpenGL system than a 2D system like X-Windows.
>
> May I ask what kind of total resolution you are aiming for? What is the p=
rojection area?
>
> Have you solved the problem of the projectors? Were you planing to use re=
ar projection or front projection? The way I see it, with front projection =
you would have a problem, since the projectors typically bleed quite a bit =
of light around the outside of their images, the joining lines between proj=
ectors would be very visible?
>
> It's definately a very cool idea, the open source planetarium. Is there a=
 website?
>
> Richard Unger
>
>
>
>
>
>
>
>
> > -----Urspr=FCngliche Nachricht-----
> > Von: lin...@li...
> > [mailto:lin...@li...] Im
> > Auftrag von De Gyves
> > Gesendet: Samstag, 11. M=E4rz 2006 02:02
> > An: lin...@li...
> > Betreff: Creating a planetarium using Ruby
> >
> > There is a possibility to create an open project to build a
> > planetaruim star projector. I have already made some
> > configurations using Ruby+Debian to enable about 4 screens.
> > Maybe it is not necessary to use Ruby (because of Xinerama)
> > to accomplish the project, but, the question is: how many
> > screens can manage Ruby? I think that ~20-30 video cards
> > would do the work using projectors instead of monitors for a
> > planetarium. Can Ruby work with this number of cards? Or,
> > must I to do it with Xinerama? Has anyone made something like this?
> >
> > Of course, because of the ceil of a planetarium is not plane
> > but concave, I'll have to recode some stuff in the drivers or
> > somewhere else.
> >
> > --
> > V=EDctor-Polo de Gyv=E9s Montero.
> > (52) 55 2771 2423 (Cellphone in Mexico City)
> > war...@ho... (just msn, don't send mail)
> > (52) 971 71 20990 (Phone in Juchit=E1n, Oaxaca)
> > Address: Independencia street & Morelos avenue, Segunda Secci=F3n,
> > ZIP: 70000, Juchit=E1n, Oaxaca, M=E9xico.
> >
> >
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>

--
V=EDctor-Polo de Gyv=E9s Montero.
(52) 55 2771 2423 (Cellphone in Mexico City)
war...@ho... (just msn, don't send mail)
(52) 971 71 20990 (Phone in Juchit=E1n, Oaxaca)
Address: Independencia street & Morelos avenue, Segunda Secci=F3n,
ZIP: 70000, Juchit=E1n, Oaxaca, M=E9xico.