Rear-Projected Snow?

[StradivariusBone]

We're doing a show that requires an almost perpetual storm brewing outside. Aural effects we've got covered, but instead of the mess and fuss of a snow machine I was wanting to experiment with a VGA projector running an eternal video of a snowfall, preferably projected from the back of the set. There's a set of French doors and a window directly above that are the only transparent openings in the set.

I did do a search, but a lot of it came up with the machines or bags and only mentions of projection. Anyone have experience that they'd be willing to share?

Thanks!

 

[MarshallPope]

I've only used snow projections as front projection, washing over set, cast, everything, but I think your rear projection would work wonderfully. The only thing that you may want to think through is how distracting the constant movement in the background would be throughout the entire show.

 

[ruinexplorer]

How much space will you have? Rear projection could eat up valuable real estate that could be better used, but it could be a great effect if you can spare it. Are you planning on the openings in the doors and window being the projection surface or will there be a screen behind them?

 

[MarshallPope]

How much space will you have? Rear projection could eat up valuable real estate that could be better used, but it could be a great effect if you can spare it. Are you planning on the openings in the doors and window being the projection surface or will there be a screen behind them?

Going off of that, one of the great things about projected snow is that it is fairly forgiving of keystoning issues. You may be able to cheat a steeper angle than you normally would be able to, if you are short on space.

 

[lwinters630]

Consider lighting angles to keep them off the screen. Have a bright projector. Plan how to fade your projector between scenes. You could run it through a video editor or switcher.

Other options are scene machine or gobo rotators.

 

[StradivariusBone]

How much space will you have? Rear projection could eat up valuable real estate that could be better used, but it could be a great effect if you can spare it. Are you planning on the openings in the doors and window being the projection surface or will there be a screen behind them?

I was hoping to determine what material will work best to place over the openings. Was thinking scrim, but I'm not sure how much will show through. Though it doesn't have to be super visible, but provide the impression that it's snowing/blizzarding outside. We've got an abundance of space backstage (20-30' if we angle it).

Consider lighting angles to keep them off the screen. Have a bright projector. Plan how to fade your projector between scenes. You could run it through a video editor or switcher.

Other options are scene machine or gobo rotators.

Thought about the gobo rotator, we've got one so it's an option, but it's a bit noisy. The projector outputs 3300 lumens and I was hoping to run it off QLab, I'm just having trouble getting it to output to the secondary screen. I'm using version 2 (the free one), so I'm not sure if that's a disabled feature. I thought it said somewhere you can do at least 2 screens for free.

 

[ruinexplorer]

A standard sharkstooth scrim won't work for rear-projection. One thing you might want to consider is buying a used rear projection mat (like this) and cut it to size and frame it. That way you know that you have an effective rear surface. There are also other, less traditional options that are discussed in the multimedia forum. You will need to determine how transparent the surface needs to be (to allow maximum brightness) and the viewing angle needed. The greater the transparency, the narrower the viewing angle, the brighter the image, and the brighter the "hot spot".

Are there entrances through the French Doors? Do you need space between the window and the projection surface?

 

[StradivariusBone]

A standard sharkstooth scrim won't work for rear-projection. One thing you might want to consider is buying a used rear projection mat (like this) and cut it to size and frame it. That way you know that you have an effective rear surface. There are also other, less traditional options that are discussed in the multimedia forum. You will need to determine how transparent the surface needs to be (to allow maximum brightness) and the viewing angle needed. The greater the transparency, the narrower the viewing angle, the brighter the image, and the brighter the "hot spot".

Are there entrances through the French Doors? Do you need space between the window and the projection surface?

We've got an older projection screen (not sure if it's rear-project capable) and a brand new one that is. One other thought was hanging it behind the set, but it's not tall enough to get the french doors and the window on the balcony directly above it. The other thing I was thinking about was dropping the cyc and projecting on to that.

The doors are used for entrances/exits so that was another consideration with rear-projecting. There's about 20' from the doors to the back wall.

 

[MarshallPope]

You may want to try black scrim layered downstage of white grey vinyl tablecloth. The vinyl transmits light fairly well, an then the scrim would hide the whiteness of it.

 

[ruinexplorer]

If you have a black scrim, you could possibly project onto it with the cyc immediately behind it. The biggest issue you will run into is needing to create a larger image (drops your brightness) and making sure that there is little ambient light on it to make the projection as noticeable as possible. If you rear project, you can possibly have a smaller image by still getting the projection surface a bit closer to the doors/window. This will help your brightness by getting the image smaller and by being a transmissive surface instead of a reflective surface (allows for higher contrast).

How far apart is the window and doors? Can you use a second projector? You could still have a single output to feed both if you use a distribution amplifier.

 

[StradivariusBone]

If you have a black scrim, you could possibly project onto it with the cyc immediately behind it. The biggest issue you will run into is needing to create a larger image (drops your brightness) and making sure that there is little ambient light on it to make the projection as noticeable as possible. If you rear project, you can possibly have a smaller image by still getting the projection surface a bit closer to the doors/window. This will help your brightness by getting the image smaller and by being a transmissive surface instead of a reflective surface (allows for higher contrast).

How far apart is the window and doors? Can you use a second projector? You could still have a single output to feed both if you use a distribution amplifier.

I was hoping to rear project to avoid having to spread my projected image too terribly wide, for the exact reasons you specified with brightness. The windows are on the second story, directly above the first story doors. I can probably source a second projector if needbe. We're finishing the set this week and can troubleshoot this. I think, like with most things in life, trial and error will rule the day.

I appreciate the direct insight thus far! I will follow up with the different experiments.

 

[carproelsofly]

Can you project onto two pieces of mirror, at a slight angle to each other, so that they reflect back to the two projection surfaces without having to fill all of the space in between?

There will be some math, or some trial and error, in finding the ideal location for the projector/mirrors so that the source is obscured.

 

[lwinters630]

I, I'm just having trouble getting it to output to the secondary screen. I'm using version 2 (the free one), so I'm not sure if that's a disabled feature. I thought it said somewhere you can do at least 2 screens for free.

I am Not sure what you mean by 2 screens. do you mean one image spread over two projectors? or the same image on two projector?

you may need to daisy chain The projectors or use and distribution amp from your computer.

 

[StradivariusBone]

I am Not sure what you mean by 2 screens. do you mean one image spread over two projectors? or the same image on two projector?

you may need to daisy chain The projectors or use and distribution amp from your computer.

It seems like QLab designates the first screen as your computer monitor (though I know you can change that). I'm trying to use version 2 on a MacBook to output to a projector. It can see it, I've patched it in the software correctly, but it still has an X on the cue itself. It will play on the monitor so I know it works. I'm just thinking that maybe the free version disabled the second video output feature.

 

[TheaterEd]

I've never worked with Qlab, but I have had issues with not being able to project videos if my monitor's resolution is different than my projectors resolution. Might be worth a shot to make sure they are set to the same resolution.

 

[StradivariusBone]

It actually recognizes the different resolutions of the screens. On the macs, they allow you to "place" where your secondary screen is relative to your primary. QLab sees that second screen and it allows me to patch it in and also align the cross-hairs to center the video effect over the secondary screen. When I select that patch on the cue, it gives me the red X and it won't play. Not an entirely huge issue. We do have a backup computer that can run independently (which would save us on cable since we can park it backstage). I'm just wondering if it's the version I have. I wouldn't mind buying the software, but if this is not a license issue I might have my reservations then.

 

[sk8rsdad]

According to the feature comparison chart on the vendor website, the free version of QLab supports a single display.

http://figure53.com/qlab/buy

 

[StradivariusBone]

According to the feature comparison chart on the vendor website, the free version of QLab supports a single display.

http://figure53.com/qlab/buy

Right, but does that mean it has to be the display on the computer itself? I wasn't sure if that meant a single output, regardless of your display. I emailed them in any event.

 

[sk8rsdad]

Right, but does that mean it has to be the display on the computer itself? I wasn't sure if that meant a single output, regardless of your display. I emailed them in any event.

Beats me. I would guess it depends on how your computer is set to output. If a projector is connected and the computer is set to mirror the desktop then it should count as a single display. Otherwise, I would think a projector counts as a second display. We pay for QLab since we find it useful and would like to see Figure 53 stay in business.

 

[StradivariusBone]

Beats me. I would guess it depends on how your computer is set to output. If a projector is connected and the computer is set to mirror the desktop then it should count as a single display. Otherwise, I would think a projector counts as a second display. We pay for QLab since we find it useful and would like to see Figure 53 stay in business.

Well they do offer the free version for the purpose I'm using it for, trial and error. I wanted to make sure it would fit our needs before plunking down the change necessary. Not trying to put anyone out of business.

On a positive note, I'm now looking at a beautiful snowfall in my office (albeit in sunny Florida) via QLab 2 displaying on my secondary projector. QLab support mentioned that to troubleshoot a bad cue, you just hover over the cue and a dialog pops up telling you why it's angry. In this case it did say I needed a Pro Video License, however in my attempts to get the thing to work I set it up to run on multiple displays and that's what invalidated it. After building a new cue, I was able to select the correct display output and voila!

I'm now looking into purchasing the software, since I'd like to take advantage of it's multiple outputs for audio.

Now to make it snow on our mansion in 1930's Connecticut...I will update this post with results from our experimentation.