# Projections on to Cyc



## klloveall (Nov 1, 2009)

My schools second show requires some very fast scene changes (and some other just cool effects), and I came up with the idea of just projecting backdrops on the cyc so that we could do them with some short animation between, such as like a Google earth sort of fly-over. Talking with my directors they liked the idea, but were concerned as to how easily and cost-effectively it could be done. I came up with 4 different ways of doing it (in order of what I think would be the best and most cost-effective):

1. We project from behind the cyc, and while I know that much less of the light would go through than if we used an RP screen, it would be cheaper. Our school very recently upgraded it's computer system, and has a bunch of projectors left over. What I was planning to do was put a lens (I'm not sure of the exact focus-distance yet, I'd still have to do the math, but the demonstration-type lenses that are used in science classes) in front of the projector (to get a short throw distance on it) and then stack 3 projectors on each side (SL and SR, 6 in all) to mesh together the image and get enough brightness to be able to see it on the other side of the Cyc.

2. We project from in front of the Cyc at a very sharp angle, using the same lenses to get a big enough angle on them, and then use Adobe After Effects or Premier to letterbox the video to correct for the keystoning (since I don't think that the build-in keystone correctors could correct for as steep of an angle as I'm imagining (about 60 degrees from horizontal to the bottom of the image).

3. Use same projection method as 1, however with an RP screen. (most likely cost-prohibitive).

4. Use an LED curtain. (almost guaranteed to be cost-prohibitive)

Any comments/concerns/comments would be highly appreciated before I go and talk with my directors again.

Thanks,
Kenny

P.S. If anyone has any other ideas than what I have listed above, I'd love to hear them.


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## klloveall (Nov 1, 2009)

Oh, and our stage is about 40' deep, 50' wide and about 18' tall (with borders). the size I want to project would be about 18' by 45' or so. We also have about 10' behind our cyc to the back wall.


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## JChenault (Nov 1, 2009)

What is the cyc made of? If muslin is it seamless?

If you do a rear projecton o muslin, the audience will see the bright spot of the projector if it is in their view. If you do a front projection there will be no bright spot.

If you have any seams they will show up as black ugly lines.

It is hard to merge images. It was not clear to me from your post how many projectors you want to use to fill the cyc, but if you want them to appear to be a single image, you will need some special software such as 'Watchout' by Dataton to merge the multiple images into a single one. If you are not going to use something like watchout, you need to think about your images so they will not suffer from this problem. IE instead of doing a single continuous image, you might need to have several smaller ones.

(Again I am not sure if the area each projector wants to cover). You need to be careful about too wide a lens if you are using rear projection. The light from the projector wants to travel in a straight line. When it passes through the screen, it tends to be brighter on the axis of directin it started out in. So if you have a lens that spreads too fast the sides of the image will be dark to someone sitting in front of the image.


Front projection is probably a better approach for what you are talking about based on what I have heard you say. ( for option 1 and 2 )


When you are planning your lighting - make sure that you don't have any light on the cyc. This means no actors closer than six to eight feet - and/or just side light when you move upstage. Also consider colors. If you have a white floor, the bounce from the floor will wash out your projections.

I


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## Esoteric (Nov 1, 2009)

What John said.

To emphasize, I have spent much of my 10 years in lighting and video design fighting bounce from the lighting on my projections. You will have to be very careful.

By the way, depending on your screen size, there are also harware options out there.

Mike


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## museav (Nov 2, 2009)

To verify, you want to get an 18' high by 45' wide (2.5:1 format) image and have 10' total distance behind the cyc to the wall. You plan on using existing projectors and sticking some type of secondary wide angle lens in front of them to shorten the throw distance.

Unless you use mirror systems, rear projection looks like it would require a matrix array, maybe 2x5, of edge blended projectors and some advanced processing. Even then, the secondary lenses will probably present some problems in getting everything aligned and matching.

The front projection option may still have some problems due to the angle, if extreme enough it could affect focus as well as keystoning. And you'd still probably need at least two edge blended projectors.

Another option would be an array of rear projection cubes or LCD flat panels as used in video walls, although an 18'x45' array would require quite a few devices and again, the appropriate processing.

And maybe I misunderstood the intent, but if the proscenium/stage is 18' high and you are projecting an 18' tall image during scene changes, wouldn't the projection be lighting (front projection) or backlighting (rear projection) the scene change? Might you be better with a smaller image overhead so as to draw attention away from any activity on stage?


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## Chris Chapman (Nov 2, 2009)

If you are having problems hanging the projector and having to deal with extreme keystoning, considering using a projector mount dropped from the structural steel in front of your proscenium. Your throw distance will start to get as wide as you want to go. You'll need a projector mounting kit ($150), the approrpiate amount of pipe ($50) and an I-beam Clamp. 

We do this all the time, and run the projector with a dowser and control the playback using Rosco I-Cue Software.

You will need to mask the projector for maximum effect though.


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## derekleffew (Nov 2, 2009)

Chris Chapman said:


> ...and run the projector with a dowser ...


douser.


Chris Chapman said:


> ... and control the playback using Rosco I-Cue Software.


I suspect you mean Rosco Keystroke software.



(Isn't that the oddest looking DMX console? [Complete with mute groups/assigns!])


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## Chris Chapman (Nov 2, 2009)

Thanks Derek. Long touring weekend and a put-in this morning has me somewhat burnt out.


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## klloveall (Nov 2, 2009)

JChenault said:


> What is the cyc made of? If muslin is it seamless?


I know that it's seamless and I believe that it's muslin.


JChenault said:


> It was not clear to me from your post how many projectors you want to use to fill the cyc


I've changed the plan a little bit, after doing some research I discovered that the biggest image our projectors can project is 20' images, (and I was planning on 30'). So, I'm now planning on having three side-by-side and having a small groundrow in front to mask the parts that won't have projection on them.


Chris Chapman said:


> We do this all the time, and run the projector with a dowser and control the playback using Rosco I-Cue Software.


Two questions:
1. How do you prevent actors from getting in the way of the projected image?
2. About how much does the Rosco system cost?


Esoteric said:


> there are also harware options out there.


What might the hardware options be?


museav said:


> To verify, you want to get an 18' high by 45' wide (2.5:1 format) image and have 10' total distance behind the cyc to the wall. You plan on using existing projectors and sticking some type of secondary wide angle lens in front of them to shorten the throw distance.


Yes, that's correct.


museav said:


> rear projection looks like it would require a matrix array


Yes, I was originally planning to do two projectors side-by-side, but now I'm having to do 3 projectors side-by-side (see above).


museav said:


> And maybe I misunderstood the intent, but if the proscenium/stage is 18' high and you are projecting an 18' tall image during scene changes, wouldn't the projection be lighting (front projection) or backlighting (rear projection) the scene change? Might you be better with a smaller image overhead so as to draw attention away from any activity on stage?


The purpose is more to allow scene changes to happen fast, not to mask them, and also to have some animations between scenes. Also, we didn't really want to have a bunch of different backdrops flying in and out (mainly we don't have that many linesets).

I must say thank you all for all the input and any more would be greatly appreciated. Also, I have two more questions:
1. About how much would it be to rent an RP screen 18' X 50'?
2. About how much would an LED curtain/wall cost to rent of the same size?

Thanks,
Kenny


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## Chris Chapman (Nov 3, 2009)

klloveall said:


> Two questions:
> 1. How do you prevent actors from getting in the way of the projected image?
> 2. About how much does the Rosco system cost?
> y






In my setup the projector is hanging off of a projector mount roughly 18 feet off the deck. You are projecting over your actors and scenery.

Last time I checked Rosco Keystroke is running $387 from BMI (it's gone up). You will also need DMX line, and VGA cable.

I use Keystroke so the changes can be cued from our Lightboard. If you have the manpower, you could just put a tech on the Computer to advance your PPT. Then you'd only be looking at the mounting hardware and pipe.


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## museav (Nov 3, 2009)

klloveall said:


> The purpose is more to allow scene changes to happen fast, not to mask them, and also to have some animations between scenes. Also, we didn't really want to have a bunch of different backdrops flying in and out (mainly we don't have that many linesets).


Which still leaves it open that an image filling the stage opening will either be interfered with by anything in front of it with front projection or backlight anything in front of it with rear projection. That may work, at least with rear projection, for virtual sets, however you noted running some animations during scene changes and that would mean that anything happening in front of the screen would interfere with or be backlit by those images.


klloveall said:


> I must say thank you all for all the input and any more would be greatly appreciated. Also, I have two more questions:
> 1. About how much would it be to rent an RP screen 18' X 50'?


Unless somebody has one laying around from a similar application, you probably won't find an 18'x50' rear projection screen for rent as that is definitely a non-standard format and would be a custom screen. And if you did it find one you'd still have to deal with trying to get an 18' tall image with only 10' of total depth behind the screen, which would seem to require substantial mirror systems or maybe a 2x4 array of projectors or something like that.


klloveall said:


> 2. About how much would an LED curtain/wall cost to rent of the same size?


This likely falls into the "if you are asking how much, then you probably can't afford it" category. A typical indoor LED tile is about 18"x20", so you are talking a maybe 12x30 or 11x33-34 array. Then you have to build some frame to support an array that large. And find a processor that can handle that size array. And figure out how to provide the 55,000-110,000W or so of power that might be required. To give some reference, it has been reported that the 4mm pixel pitch, nominal 15' tall by 26.5' wide LED wall at Comcast Center cost around $2.2 million. Your 18' tall by 50' wide application calls for a wall that would be about 2.26 times that area, so say around $5 million. A monthly rental might be $500,000 or more if that was even possible. Of course, you could go with lower resolution tiles or a 'curtain' and maybe reduce the power consumption and perhaps the number of tiles. If you're serious about pursuing this I can put you in touch with some manufacturers.


While the concept is great, the practical realities of physics, physical space and budget may make it difficult to realize.


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## ruinexplorer (Nov 3, 2009)

For low resolution LED solution, you can rent an LED curtain from Rose Brand. I don't think this is the resolution that you are looking for. 

I agree that you should drop the idea of filling the entire cyc with projection and either concentrate on the upper portion of the cyc or the upper portion without filling the entire width of the stage. Consider how they did this digital scenery for Peter Pan (article from Live Design magazine). When doing the scene, it adds to it, but during scene changes, it draws attention from the perfomance area. 
Or to consider the smaller image and how it helps, consider Jersey Boys (look at the seventh photo for video image). They use LEDs as opposed to projection and that display flies in and out, but it is just to show that you don't need to fill your entire space to have effective video.


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