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New projection Project, Help plz! ty

Discussion in 'Multimedia, Projection, and Show Control' started by Stoldal, Dec 30, 2007.

  1. Stoldal

    Stoldal Active Member

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    For the next musical I am working on,the director wants to use three large projection screens. I attached a picture of a rough idea of how the screens are going to be. The director want to do two things.
    1)project one image a crossed all three screens
    Both Pictures and videos

    2)Use light to project even washes of color on the screens. (note: that i was planing to use LCD panels to project the colors)
    I am normal the lighting director, but I have done some projection for other plays I have worked on. I have also done some tech work for one of the local news stations.

    I have about $500 to do this, I have the projectors, and the screen are going to be built by a parent using Trapeze Plus Spandex http://www.iweiss.com/stage/fabric/specialty.html
    These are going to be larger then average screens.
    Tell me what other information you guy need.
    Thank you for your help!!
     

    Attached Files:

  2. wolf825

    wolf825 Senior Team Emeritus Premium Member

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    so.....what is your question that you need help or ideas for? You say you have the projectors..the screens are being built.. Is it lighting the screens? is it making the screens? what size are they?

    ?

    I would front project the images and rear project the colored light..or vica versa....it will make controlling either (well--dimming the color wash) and not washing out the image a bit more 'manageable'..not much but a bit more...IMO.....

    -w
     
  3. Stoldal

    Stoldal Active Member

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    Ok, the problem is how to project one image across all three screens. The screens are at three different angles.
     
  4. SHARYNF

    SHARYNF Well-Known Member

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    We get this question alot

    Depending on your setup, one way is to use a PC with a graphics card that can support three monitors http://www.eventdv.net/Articles/ReadArticle.aspx?ArticleID=37848

    http://www.tomshardware.com/forum/183999-30-matrox-triplehead2go-span-displays

    You then need to split your desktop across the three outputs, use the VGA/DVI connection and run your video across the three monitors. In theory this should work have to say I have not personally done this specific configuration.
    Since you are dramatically magnifying the image, usually it is recommended to have a high resolution image to start with

    Couple of points to keep in mind
    The matrox trypplehead2go, attaches to the vga output of your system, they have two versions analog and digital, if your projectors are analog, you need to get the analog version. At the same time you need to make sure your video card on your player will support the triple resolution you are looking for, Check out

    http://www.matrox.com/graphics/en/corpo/products/home.php#dws

    You need to look at the resolution of the three projectors (need to match) and then make sure your video card supports 3x the horizontal resoulution, also you need to make sure that your video playback application will support this resolution.

    Potential problems is there is no edge blending, but also unless you use a dual video out card on your pc you are going to have the pc desktop also be visible. As I said I have not had the the time to test this all out, but it is something I am looking at as more and more people do want to split stuff across multiple screens

    Outside of your budget and Mac only there is a product called ProVIdeo Player
    http://www.renewedvision.com/pvp.php

    Worship systems are starting to use this feature, and so prices are starting to come down
    This approach gives the most flexibility but has higher cost

    There is also a product called Arkaos, which offers another alternative
    http://www.arkaos.net/software/vj_description.php They have a free trial that you can down load and works for 21 days with no limitations

    Another approach, get three identical dvd players, make up your own three custom dvd's splitting the feed into three parts, and use an IR remote to start stop the three dvd players

    In general getting it all to work perfectly is a bit trickey in all cases especially if you don't make your video with the idea of spreading it across three projectors from the start

    Sharyn
     
    Last edited: Dec 30, 2007
  5. museav

    museav CBMod CB Mods Departed Member

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    I'm not clear on just what you are trying to do with that arrangement. My first thought was that the video would be one projector projecting over all three screens, but you mentioned having projectors plural. And while it may just be the sketch, the screens shown both do not appear to be a standard format and they seem to overlap. It's also not clear what is happening between the screens or if that might result in some issues regarding light coming from or projecting through those gaps. So can you explain a little more about what you are trying to do and what you were planning to do to accomplish this? Are you using one projector or three? Where will the screens be located and might they be affected by other lighting?

    There could be some challenges such as how you get the projected image and lighting to fit the screens (or if that matters) and how you get the separation between images that the sketch reflects. If you start trying to do things like use projectors on their sides to get the vertical format shown this not only might not be something the projectors support, but it could also greatly complicate the video processing required.
     
  6. Stoldal

    Stoldal Active Member

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    Thanks for the help guys. What we are trying to do is, i have the three screens, the director wants to project different landscapes, and buildings, on the screen. He want the gaps between the screens. I am thinking that i have to use three projectors, one for each screen.

    I just don't know what the easiest way to project the one image on all three screens. The production is in 5 months, so if this get to costly or to complex we may try a different idea.

    I hope what i am trying to do is clear, if it is not i will try clarifying it.

    Thanks
     
  7. icewolf08

    icewolf08 CBMod CB Mods

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    Short of using a true media server like the HES Catalyst or PRG's M•Box your best bet is probably a multiple output graphics card as Sharynf said, or a computer with multiple graphics cards.

    Next, screen size, if you get longer than 16:9 proportions you may find that your projectors can't produce an image in the shape you need. This means that you will either need a digital mask around your images which will leave you with "video black" bleed, or you need to create a physical mask so that the images fit on the screens correctly. Here is an example of an odd shape projection I did for the musical "Violet."
    [​IMG]
    [​IMG]
    [​IMG]
    The projection surface you can see without a projection in the third image. I created a digital mask with some feathering that we aligned to the "screen" and then dropped the images and some video behind. This was done with one projector, and since the aspect ratio of the "screen" was no 4:3 which is the supported aspect of our projectors the actual image size significantly larger than the "screen" then masked down.

    A media server or the multi monitor technique will allow you to align multiple projectors and then have a single image span across. For that you may need physical masks to eliminate bleed from one projector onto a different screen if your projectors don't support non standard aspect ratios.
     
    Last edited: Jan 2, 2008
  8. museav

    museav CBMod CB Mods Departed Member

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    So are you wanting one image spread across all three screens or the same image on each screen (the same image three times)?

    Since the screens are together and appear to even overlap, then if it is one image across the three screens and you want the gaps, a single projector probably makes more sense. Much simpler and the resulting image area looks like it would more closely match a projector's native format, which could be 5:4, 15:9 or 16:9 but is most likely 4:3. One potential factor with this approach would be the projector output and what kind of image you get with the screen size, screen material and other lighting hitting on the screens.

    If you need to use one projector per screen to get sufficient image quality, then a solution like Sharyn's might be a better option.

    If you do not digitally or physically mask the image as icewolf suggested then since the image would be projecting through the gaps you'd want to be sure there is nothing behind the screen that will reflect the image.

    If you want the same image on all three screens simultaneously then you would need three projectors and to get the image areas shown you would probably need to both physically mask the projected image and consider that image format in selecting and putting together your media.
     
  9. Stoldal

    Stoldal Active Member

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    I need to project one image acrossed all three screens. I think that using one projector will work. I think that i will use 4:3. Now i need to find a projector that will have a high enough output. the projectors that i have only has 1000lumes. What do you think will be a high enought output. It is going to be a large screen, lets say 15'x15'. Also, what is the best cable for me to use, i know it should be a VGA cable, or DVI, but both of those cable are very costly for long cable runs. The cable run is going to be 50'+.
     
  10. SHARYNF

    SHARYNF Well-Known Member

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    Issue of deciding the lumens needed is going to be the amount of ambient light. in addition remember to get an image of that size you are looking at typically quite a long distance from the screen to projector, it will depend upon the lens of course I am assuming you are looking at front projection?

    vga works best but you need to see how image is generated, if the image is just video playback then composite or s video will work best since you will not have to have the image re scaled

    Sharyn
     
  11. kwotipka

    kwotipka Active Member

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    Off the top of my head, I would have to go with the general thought that one projector is going to be the way for you to go. Dealing with multiple projectors, controlling and playing back your media in sync is probably out of your price range.

    Since you have some time, first get with the carpenters and discuss the sizes you are dealing with. Design the three screens (outlines like in your picture) in something like powerpoint and then project them onto a curtain or wall so you can get an idea of what sizes and output your projector can handle.

    Then, find a Final Cut Pro geek and get them to overlay a garbage matte over your video. This will cookie cut out the shapes making it easier to control spillage and you can post your footage in another application if needed.

    When you are finished, simply playback the files from your computer or burn to DVD, whatever is easier.

    As far as projection and lighting goes, if you only have a 1000lum projector, then you will almost have to do front projection. Especially if you are projecting onto spandex.

    kw
     
  12. museav

    museav CBMod CB Mods Departed Member

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    It's difficult to say what projector may be appropriate since we don't know how much other light may be hitting the screens, the properties of the Trapeze Spandex as a screen and several other potential factors. Even the lens used and the age of the lamps could enter into it, a nominal projector rating is really only accurate for the specific lens used in testing and with a new lamp, using an alternate lens and a lamp with some hours on it could significantly reduce the output, I've seen projectors that are working fine but putting out about half their rated output due to such factors.

    By the typical guidelines and with a typical matte white projection screen, a 15'x20' image, which would be the actual standard video image for your 15'x15' screens, would suggest a minimum of about a 5,000 lumen projector. Due to any light on the screen, you'd often realistically want perhaps 2 to 3 times that. That is probably not practical. Since the images are likely not the primary focus, you may be able to work with lower image brightness, however you may have a few factors to overcome.

    If you look at the great example icewolf posted, you may note that the screen is overhead when being used for projection, which probably helped tremedously in keeping stage lighting off the screen. That's a good approach, but with a 15' high screen I don't know if it is practical for your application. So you may have to look at how you can keep any light on the screens other than the projectors to a minimum.

    The screen itself is another factor. I can't find any real data on the properties of the Trapeze Spandex as a screen. They do say it can be used for front or rear projection and typically such products have a fairly low 'gain', to serve as a rear screen the material has to pass and diffuse light while as a front screen it has to reflect light, so being able to do both means some light is lost in either case. This effectively reduces the image brightness and that would have to be compensated for by a greater projector light output.

    So you may just have to see what you can get in your application, but I would guess that a projector more along the lines of a minimum 3,000 to 5,000 lumens might work and any brighter might give you more flexibility.

    I wouldn't consider DVI for the run, DVI is not meant to run larger distances and while you can get cable that will support a 50' run, any DVI cable that works well at that distance is expensive. Not to mention that if it is DVI-A, then it is essentially VGA, just on a different connector. I agree with Sharyn that what is best likely depends on the source. If the source is a computer you might also want to consider preparing the video in the same resolution as the native resolution of the projector, that will keep the projector from having to scale the signal and likely give the best quality.
     

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